128

ENGLISH MECHANIC AND WORLD OF SCIENCE.-No. 292.

The Enfield bullet being 100 grains heavier than the Chassepot, and being fired with 15 grains less powder, it has a much lower initial velocity; being of large diameter, the atmospheric resistance to it is great, so that even its comparatively small initial velocity is rapidly reduced. Even the first 300 yards is traversed by the heavier Whitworth bullet (of 530 grains) in less time, and from that point onward its superiority in accuracy and penetrative power increases with the range. the Enfield at 1,000 yards is too wild to admit of The shooting of comparison with the other.

The Prussian bullet is of the same weight as the Enfield, and fired with the same charge. Its diameter is somewhat less, and if other things were equal, its range, &c., should be for that reason superior to the Enfield's; but as a matter of fact they are worse, owing to its large bore and the large paper envelope of the bullet. JOSEPH WHITWORTH & Co. 44, Chorlton-street, Manchester.

be in conjunction with x Leonis at 2h. 40m. in the
afternoon of the 24th; inasmuch as both the star and
planet will at that time have set for more than an hour
in England. We may add that he is travelling through
Leo during the whole of this month.
the heavens, and is visible all night long. He rises soon
Jupiter is now a brilliant and conspicuous object in
after sunset during the whole of this month. Souths
on the 1st at 3h. 2m. a.m., and on the 30th at 51m.
November. The appearances presented by his belts, may
after midnight. He sets, of course, in bright daylight.
He remains in the constellation Taurus all through
with adequate optical means; inasmuch as it is certain
well engage the attention of all who may be furnished
that changes on a stupendous scale are constantly in
progress in his cloudy envelope. It is most important
that the student should possess the power of sketching
rapidly and truthfully what he sees. Authentic drawings
of celestial objects cannot be too numerous; they may
stand the theorist in good stead when a moot point is to
be decided. They must, however, be authentic, and made
ad naturam with the eye to the telescope. Memory can
never be trusted, even for ten minutes. To facilitate the
representation of this particular planet, a number of
ellipses, having their major and minor axes in the pro-
portion of 1 to 927, should be prepared. This may con-
cutting it out, and then running a pencil round the
veniently be done by striking such an ellipse upon a card,
boundary of the opening, while the card is laid upon
the paper to be drawn on; in fact constructing a card
stencil plate.

[OCT. 28, 1870.

satellite at 11h. 3m. The egress of satellite 3 from transit will occur at 7h. 50m. on the night of the 23rd. The 1st will be eclipsed at 4h. 33m. 12s. the next morning.

on the

the

During the early morning of the 25th the shadows will pass off at 4h. 6m., the satellite at 4h. 35m. 1h. 52m., that of satellite 1 itself at 2h. 2010. The ingress of the shadow of satellite 1 will take place at This satellite will be eclipsed on the night of the same day at 11h. 1m. 42s. occur at 8h. 20m., and that of the satellite at 8h. 46m. at 1h. 41m. the next morning. 26th the ingress of the shadow of the 1st satellite will It will reappear from occultation On the night of the 11h. 1m. The shadow will pass off at 10h. 35m.; the moon at be an eclipse of the 3rd satellite. The 1st satellite will reappear from occultation at 8h. 7m. At 5h. 17m. 13s. a.m., on the 27th there will night of the 27th, and an eclipse of satellite 2 will ceeding early take place at 3h. 51m. 7s. in the sucnight of the 29th the ingress of the shadow of the morning of the 28th. On 2nd satellite will begin at 9h. 58m., and the transit of the satellite at 10h. 41m. The egress of the shadow will a.m. on the 30th. On the night of the 30th at 7h. 17m. occur at 12h. 35m., and that of the satellite at 1h. 18m. the ingress of the shadow of the 3rd satellite will com. 11h. 8m. The shadow will pass off at 9h. 51m., the planet at mence, and that of the moon casting it at 8h. 39m18h. 27m. 26s. (astronomical time) on the 30th of Finally, the 1st satellite will be eclipsed at November, or, according to our civil reckoning, at the sun now to be conveniently observed. He is on 6h. 27m. 26s. in the morning of December 1st. Saturn is still an evening star, but sets too soon after and on the 30th at 1h. 16m. the meridian on the 1st at 2h. 57m. in the afternoon, the confines of Ophiuchus into those of Sagittarius. He is travelling from from the constellation Gemini into that of Cancer. He favourable position for observation. Uranus is an evening star, and is coming into a rises soon after 9 at night, in the beginning of the He is passing Cancri, a little to the west of which he may be found. The only star of any size in his neighbourhood is 2 month, and about a quarter past 7 at the end of it.

crosses about 8h. 30m. on the night of the 30th. He He is on the meridian on the 1st, at 10h. 32m., and Neptune is also an evening star, and visible all night. remains in the constellation Pisces.

ASTRONOMICAL NOTES FOR NOVEMBER. BY A FELLOW OF THE ROYAL ASTRONOMICAL SOCIETY. THE right ascension of the sun at Greenwich mean noon on the 1st of November is 14h. 25m. 59.888., and his declination sonth 14° 28′ 17.3". He is consequently self, his satellites will present a series of interesting In addition to the physical features of Jupiter himin the constellation Libra, and situated to the W. by phenomena. N. of the star a in it (vide map, Vol. X., p. 545). Hegress of the shadow of satellite 1 will take place. It At 1h. 41m. a.m. on the 2nd the inrises on the 1st day of the month in London, at 6h. will be followed at 2h. 38m. by the satellite which 56m. a.m., and sets at 4h. 32m. p.m.; and on the last casts it. At 3h. 20m. the shadow of the 3rd satellite will day at 7h. 44m. a.m., and 3h. 54m. p.m. respectively; satellite will pass off. At 4h. 53m. satellite 1 will itself come on to Jupiter's limb, at 3h. 55m. that of the 1st the night at this latter date being thus obviously nearly leave Jupiter's face; and at 5h. 50m. the shadow of satel16 hours long. The equation of time to be subtracted lite 8 will also pass away. from that indicated by a meridian instrument or sundial amounts on the 1st of November to 16m. 17.178., 2nd, and it will reappear from occultation by the planet lite will take place at 10h. 51m. 21s. on the night of the An eclipse of the 1st satelat 2 o'clock the next morning. On the night of the 3rd to Jupiter's limb, as will the satellite itself afterwards at 8h. 9m. the shadow of the 1st satellite will come on at 9h. 5m. The egress of the shadow will occur at 10h. 24m.; that of the moon at 11h. 19m. Satellite 1 will reThe ingress of the shadow of the 2nd moon will take be sedulously watched for by every earnest student. appear from occultation at 8h. 27m. on November 4. between the 12th and 15th of November will, of course, The marvellous star shower which annually recurs place 55m. after midnight. Later, at 2h. 44m. a.m. on It may be expected on the early morning of the 14th, the 5th, the satellite will follow its shadow. shadow will pass off at 3h. 31m., and the satellite at present, on the wane, and that no such an astounding The although it seems to be tolerably certain that it is, at 5h. 21m. a.m. be subsequently occulted by Jupiter at 8h. 50m. From be kept after midnight every night between the dates The 3rd satellite will reappear from spectacle as amazed and almost appalled us in 1866 eclipse at 7h. 37m. 8s. on the night of the 5th, only to this occultation it will reappear at 11h. 18m. can reasonably be looked for this year. 6th satellite 2 will disappear in eclipse at 8h. 3m. 19s. because the radiant point, from which the major part Watch should after 12. The shadow of the 1st satellite will come until then. Many persons, in ignorance of this, during On the which we have specified. We say on to Jupiter's disc at 3h.34m a.m., on the 9th, and satel- the last three or four years have terminated their vigil reappear from a subsequent occultation 23m. of this astonishing rain of fire emanates, does not rise "after midnight' place at 5h. 49m. It will be daylight before the moon lite 1 at 4h. 24in. The egress of the shadow will take at 12 o'clock, under the impression that as, up to that passes off. At 45m. 10s. after midnight on the 9th. therefore they had mistaken the night; the simple hour, no conspicuous shooting stars have been visible, satellite 1 will disappear in eclipse. from occultation at 3h. 46m. the next morning. It will reappear fact being, as we have said, that the part of the the night of the 10th at 10h. 3m. and it will itself The association of the November stream of meteors ingress of the shadow of this same moon will occur on above the horizon when the watch was relinquished. The heavens whence the stream appears to issue, was not commence to transit Jupiter at 10h. 51m. 11th. On the 11th satellite 1 egress of its shadow will take place at 12h. these columns. One thing we would endeavour to urge The with Tempel's comet has already been referred to in 18m., and its eclipse at 7h. 13m. 36-7s., and reappear from occul- naked-eye acquaintance with the heavens. The reason Own at 1h. 15m. a.m. on the tation at 10h. 12m. During the early morning of the for this is not difficult to apprehend; it is that the path will disappear in coming display, and that is to obtain, at once, a good upon all those who may propose to observe the forth12th the shadow of satellite 2 will enter on the planet's of any very conspicuous individual meteor may be resatellite will leave Jupiter's disc at 7h. 32m. p.m. on limb at 3h. 30m., followed by the moon casting it at corded with all attainable accuracy. Two such observa5h. 2m. The shadow will pass off at 6h. 6m. The 1st tions made at stations widely separated may be of the the 12th. The 3rd will disappear the same night in and hence the distance from the earth of the body to eclipse at 9h. 17m. 468., will reappear from this eclipse which they refer. utmost possible service in determining the parallax, at 11h. 37m. 35s.; only however to be occulted by this occultation at 2h. 43m. a.m. on the 13th. Jupiter 16m. after midnight. It will reappear from the night of the 13th satellite 2 will suffer eclipse at 10h. 39m. 19s., and will reappear from occultation On at 2h. 42m. the next morning. The shadow of the 2nd satellite will pass off Jupiter's limb at 7h. 24m.

increases on the 3rd to 16m. 18:31s.; and then, beginning to diminish, is on the 30th only 11m. 8:47s. The sidereal time at mean noon (or right ascension of the meridian, at the instant that a properly-regulated clock indicates 0 hours) is on the 1st, 14h. 42m. 17.07s., and on the last day of the month, 16h. 36m. 87-19s. The mean time at sidereal noon (or mean time of transit of the first point of Aries) is 9h. 16m. 11:57s., on November 1st, and 7h. 22m. 10.17s. on November 30th. The moon is full at 7h. 32m. a.m. on the 8th ; enters her last quarter at 8h. 59m. a.m. on the 16th; is new at 1h. 21m. after midnight, on the 22nd, and enters her first quarter at 10h. 33m. p.m. on the 29th. She is 7-9 days old at Greenwich mean noon on the 1st, 8-9 days at the same hour on the 2nd, and so on. in the afternoon of the 16th, libration will bring an At 1 o'clock additional portion of her S.E. limb into view; and on the 28th, at 3 p.m., more of her S.W. surface will become visible from the same cause. on the 11th the moon will be in conjunction with Jupiter; At 3h. 21m. p.m. and at 5h. 12m. a.m. on the 14th with Uranus, whom she may occult as viewed from stations far to the north of Greenwich; but whom, at that place, she will pass just clear of. She will be in conjunction with Mars on the 17th, at 1k. 6m. p.m.; with Venus on the 22nd, at 5h. 43m. ; with Mercury 8m. after midnight on the 22nd; and finally with Saturn at 8h. 25m. p.m. on the 24th. There will be three occultations of fixed stars by the moon this month, and-as has just been intimated-one very near approach of our satellite to the planet Uranus. She will also be in close proximity to 81 Tauri at 10h. 3m. p.m. on the 9th. Later on the same night 63 Tauri will disappear at her bright limb, at 11h. 26m., reappear at the dark limb 11m. after midnight. At 8h. 49m. in the evening of November 14th, 39 Cancri will disappear at the moon's bright limb before she has risen. After she has been up for half an hour, at 9h. 34m., the star will reappear at her dark limb. 40 Cancri will be occulted under precisely similar circumstances, its disappearance and reappearance occurring almost simultaneously with those of 39. It will be hidden at 8h. 50m., and emerge at 9h. 38m. Mercury is a morning star up to the 22nd, when he is in superior conjunction with the sun. will of course travel to the east of the sun, and become After this he an evening star. He souths on the 1st at 10h. 57m. It is evident that he is about as badly situated for observation during this month as he possibly can be. Venus is also a morning star, and (approaching as she is, like Mercury, to her inferior conjunction) in a most unfavourable position for the observer. She souths on the 1st at 11h. 10m. a.m., and on the 30th at 11h. 41m. a.m. She is in conjunction with Mercury at 8h. 36m. in the evening of the 11th.

a.m.

Mars continues to be a morning star. He souths on the 1st at 7h. 36m. a.m., and on the 30th at 6h. 39m. a.m., setting at about a quarter to 3 in the afternoon of the 1st, and about 1h. 19m. p.m. on the 30th. Although his apparent diameter is now very slightly increasing, he still presents merely the effect of a large red star, and will by no means repay telescopic observation. It is perhaps scarcely worth while to mention that he will

and

SCIENTIFIC SOCIETIES.

THE OBSERVING ASTRONOMICAL SOCIETY.

Report of Observations made during the period from
August 7th to October 6th, 1870, inclusive.

p.m. on the 15th. the shadow of the 1st moon will enter on to the The satellite itself will do the same at 8h. 47m. planet's limb. At 5h. 29m. the next morning The moon itself will follow it at satellite 1 will disappear in eclipse at 2h. 39m. 7s., observed in August was repeated, though in a rather less 6h. 9m. During the early morning of the 17th SOL OLAR PHENOMENA-Mr. Thomas G. E. Elger writes-"The magnificent display of solar spots and reappear from occultation at 5h. 31m. satellite will enter on to Jupiter's disc at 11h. 57m., mainly confined to the South hemisphere; on the the night of the same day the shadow of the 1st and 12th, the spots were small, few in number, and On striking manner, during September. Between the 7th after midnight. The shadow will pass off at 2h. 12m. The immense group observed last month, and which and will be followed by the satellite projecting it 36m. 11th, only three moderately-sized groups were visible. a.m. on the 18th, and the satellite 38m. later. 9h. 7m. 35s. at night on the 18th the 1st satellite will be at the E. limb about the 17th, but owing to unfavoureclipsed. It will reappear from its subsequent occul- able weather and absence from home I did not notice At was near the centre of the disc on August 30, was due shadow of satellite 2 will pass on to the face of the ou including the outlying penumbra which followed tation behind the planet's body at 11h. 57m. The it till the 24th, when it measured 2′ 45′′ by 1′ 50′′ withplanet at 5m. past 6 the next morning. On the 19th it; its length on the 25th was 3' 0". 7h. 2m. The egress of its shadow will occur at 8h. 41m., contained four large umbræ and many smaller ones; the transit of the 1st satellite will commence at of this group presented some remarkable features. and that of the satellite itself at 9h. 16m. During the The penumbra It succeeding early morning the 3rd satellite will disap- numbral matter, on the preceding side it was fringed with wispy peoccultation at 6h. 5m. pear in eclipse at 13h. 17m. 9s. and reappear from minute dots of every shade from black to light brown. eclipsed at 1h. 15m. 14s. a.m. on the 21st, and reappear 25th the entire group was evidently undergoing rapid which was thickly studded with from occultation at 6h. 59m. a.m. afterwards. The 2nd satellite will be! When examined with a power of 180 at 3. on the shadow of this satellite will, on the night of the 22nd, the dark spurs and serrated edges of the umbræ enter on to the limb of the planet at 7h. 23m., and be clearly indicating the cyclonic nature of the forces inThe and violent changes, the striations of the penumbra and followed by the moon casting it at Sh. 26m. The egress volved. The above group was preceded by a very long of the shadow will take place at 9h. 59m.; that of the and narrow V-shaped spot, which occupied nearly the

(EDINBURGH BRANCH).

THE ordinary monthly meeting of this society was
on Thursday, the 6th inst. Mr. Anderson,
held
owing to severe illness, was unable to take up the sub-
ject of electricity, as formerly announced, but gave
instead a lecture on "Lunar Scenery," which, with the
aid of diagrams' and variously-formed illustrations, he
rendered at once agreeable and instructive. The lec-
turer was at pains to point out, not only the appear-
ance the moon presents when properly viewed, but also
the methods taken to determine accurately what the
various lights and shadows represent.

same position as a large spot observed in August. ENGLISH MECHANIC SOCIETY OF ARTS
Several other groups were observed during the month
which presented interesting details, but they were
generally smaller than the August groups. The ap-
pearances exhibited by the large group described
above, and, indeed, by most spots of a similar class
observed this year, seem altogether opposed to the
deep excavation' theory of sunspots." Mr. T. M.
Backhouse, of Sunderland, reports "A very fine group
of spots passed the sun's centre in the northern zone
on September 21. On September 23, at 21h. 25m., it
contained two very long penumbra which were not
widely separated; the ƒ one was 74,000 miles long,
and the p one 92,000. On the 25th, at 19h. 45m., it
was only 66,000 miles long, and the ƒ penumbra was
divided into two. Another very fine group also in the
N. zone passed the sun's centre on the 24th. The di-
mensions in miles of its chief spot were as follows:-
PENUMBRA.
UMBRA.

Time. Length. Width. Length. Width.
47,000 26,000 11,000
50,000 31,500
29,500

21.-21h. 25m. abt. 72,000
22.- Sh. 25m. 50,000

23.-21h. 25m. 63,000 25.-21h. 80m. abt. 70,000

Mr. Kemp thereafter read a paper on "A Method of Heating Railway Carriages by Steam." The method proposed by him was to carry the "exhaust" steam along the train in pipes. The engineers present pointed out that the exhaust cannot be used for any such purpose, it being all required for the "draught" of the furnace. The matter is to be again brought up. It was announced that at the November meeting Mr. Boosie would read a paper on "The Manufacture of Paraffine," and Mr. Dow would exhibit a model "centrifugal railway."

On the 23rd, at 4h. 40m., I found it was divided into
four, apparently by a violent current in the middle from
p to f." Mr. William F. Denning, of Bristol, observed
the large spot visible on Sept. 21. With his 4in. metallic
reflector he could very distinctly see a black nucleus in
the S. part of the ambra. It did not appear to be
actually enclosed within the umbra, but was situated
on the margin of the penumbra. Mr. E. B. Knobel, of
Burton-on-Trent, says, that on Sept. 25, the large group [We do not hold ourselves responsible for the opinions

near the centre of the disc measured 2' 54" by 1′ 44′′.
On the 26th the two largest groups were equal in length
to 2' 44" and 2′ 36" respectively. They were distinctly
visible to the naked eye. The Rev. S. J. Johnson, of
Crediton, writes that on Sept. 21, at 4h. 30m.,a power of
70 on a 21 in. object-glass showed penumbræ on at least
spots visible on the sun. On Sept. 20, "Seven spots
were very large indeed, and arranged in five groups
each, scattered over a large surface." Mr. Albert P.
Holden, of London, referring to the large spot, says,
that on Sept. 20, when entering on the solar disc it
appeared as an elongated spot with a bright arm
stretching over half the umbra, till it joined a pro-
jection on the N. side. It was followed by a very
large group of broken masses of various dimensions.
On the 23rd (8 a.m.) the chief spot had enlarged con-
siderably, whilst the broken mass following it, had
very much decreased. The great spot was very nearly
divided into two by a very broad arm springing from
the N., the W. portion of the umbra being again sub-
divided by a similar arm on the S. side. This last was on
one side broken up very peculiarly, so that it presented
the appearance as if a handful of bright straw had
been thrown carelessly upon it. The eastern portion
of the umbra was crossed by a very bright curved
streak, which was so bright and so clearly distinct right
up to its edges as to appear more like a carved piece of
silver. On the 24th (8 a.m.) the broken mass before
referred to as following the chief spot, had almost dis-
appeared, with the exception of one small spot and a
small amount of penumbra. The great spot was also
a little smaller and quite divided by the broad arm.
A large crack appeared in this latter. Each of the two
portions of the original spot were also divided by
luminous bridges across them. On the 28th, the
appearance of the umbra was much the same, although
the penumbra was entirely changed, and a great narrow
branch had projected S. to an immense distance. This
great arm was dotted here and there with a few patches
of umbra. The broken mass which had followed the
great spot at its first appearance was now entirely
dissipated. On the 29th the two portions of the
original spot were widely separated, and much con-
tracted, and two spots to the S., which had hitherto been
of very small size, had much enlarged. The rotation
of the solar orb then carried the spot out of sight.
The chief fact impressed upon the mind by these obser-
vations is that a spot becomes dissipated in consequence
of its continued division and subdivision by the pro-
jection of luminous bridges across its various portions."
AURORA BOREALIS.-Mr. John Birmingham, of
Tuam, writes:-"Though the night of the 24th Sep-
tember, when there was no moon and a densely cloudy
sky, ought to have been extremely dark, it was, on the
contrary, about as bright as if the moon were full and
the night similarly overcast. This extraordinary
brightness began to decrease at eleven o'clock, and
continued diminishing up till midnight, when the
clouds cleared away and revealed an Aurora Borealis
of rare splendour, though it was doubtless inferior to
what, unfortunately, the state of the sky prevented
from being observed previous to eleven o'clock. The
auroral arch was wanting, but long beams extended up
from its usual position and brilliant coruscations

were flashing on almost every side towards the zenith
-even at times from the south-at precisely 12h. 40m.,
Greenwich mean time, there was a well-defined corona
with its centre at exactly Beta Andromeda. By means
of a lamp held at some distance, with the aurora as
a background, I was enabled to position three spectro-
scope lines with a small pocket instrument. These
were the usual bright band in the green, a very faint
one near it on the left, and one of medium brightness
near F. On the night of October 14, during another
remarkable display, when the intense red hue of broad
areas of light did not seem enfeebled by the rays of a
very bright moon, there was no indication of a red line
in the spectroscope. In fact there was here no line
whatever to be detected, and the white light seen in
some parts of the sky gave only the one principal line
in the green."
To be concluded in our next.)

LETTERS TO THE EDITOR.

of our correspondents. The EDITOR respectfully
requests that all communications should be drawn
up as briefly as possible.]

All communications should be addressed to the
EDITOR of the ENGLISH MECHANIC, 31, Tavistock-
street, Covent Garden, W.C.

able to J. PASSMORE EDWARDS.
All Cheques and Post Office Orders to be made pay-

"I would have every one write what he knows, and as much as he knows, but no more; and that not in this only, but in all other subjects: For such a person may have some particular knowledge and experience of the nature of such a person or such a fountain, that as to other things, knows no more than what everybody does, and yet to keep a clutter with this little pittance of his, will undertake to write the whole body of physicks: a vice frem whence great inconveniences derive their original."-Montaigne's Essays.

In order to facilitate reference, correspondents when speaking of any Letter previously inserted will oblige by mentioning the number of the Letter, as well as the page on which it appears.

SOLIDITY OF PLANETARY NUCLEI.
[681] SIR,-I note that in letter 577, p. 105, our
"F.R.A.S." (if "Inductoriam" will permit the ex-
pression) considers it almost certain that the nuclei of
the seven primary planets are neither liquid nor
gaseous. It is possible that there is evidence on the
matter as yet unknown to me; but I mast admit that
so far as the facts known to me are concerned, I con-
sider the probabilities as respect Saturn and Jupiter to
lie the other way. (Let not "Ignoramus" rejoice, by
the way, and say here are two Fellows of the R.A.S.
at loggerheads. As I told him, we have but opinions
on these matters, and know nothing certainly.) I should
be glad to have any evidence "F.R.A.S." may know
of, bearing upon, or tending to prove, the solidity of
the nuclei of the external planets. In my
Worlds," I have accumulated a quantity of evidence
"Other
bearing the other way; but I do not wish to be unfair,
and should certainly like to find room for any direct
evidence tending to show that the condition of the
outer planets more nearly resembles that of the earth
than I at present conceive to be possible. At present
I am in the unfortunate position of having no knowledge
of any such evidence whatever.

"F.R.A.S." will understand that I am not inviting
him to argument, especially to the most unprofitable
of all kinds of argument-argument where our real
knowledge is very limited. He is rather to look upon
me as a specimen of that class regarded as so trouble-
some by the "eyeglass fellow" in "Little Dorrit "-
those, namely, who "are always wanting to know, you
know."

RICHARD A. PROCTOR.

ERRATUM; AND AN APOLOGY.

[632] SIR,-In my letter about sunspots, a sentence is rendered unintelligible by a slight erratum. I wrote-"Faculæ could be distinctly recognized in central regions of the disc (they were much more obvions near the limb in three regions)." This was printed "thos regions." Mea culpa, I imagine.

I am reminded by the letter of "F.R.A.S." that "Amateur Astronomer" has asked me a question to which I have failed to reply. Perhaps this is the less important, as I really do not know even now what to say in answer. If about £3 will procure a small speculum, I should say certainly get one, and a prism and eyepiece to correspond; and build them up into a telescope, getting Browning's excellent "Plea for Reflectors," 1s., to learn what has to be done.

RICHARD A. PROCTOR.

I would clear away all the mounting, &c., from the top of the existing boiler,and fix a steam chest thereon, spherical or cylindrical as taste or necessity may as represented by the dotted lines-it may be made of this steam chest or dome, enclosing all the fire-tubes, require-carrying the conical uptake through the centre of course, as shown at A; also inserting a short tube b, as a connection between the boiler and steam chest, to carry off the wet steam from the boiler to the steam

chest.

supposed to separate itself from the surplus water in
The steam in passing through this mouthpiece is
being a little reduced in temperature, the water falling
to the bottom will descend through the pipe C to the
bottom of the boiler, if required, by means of its own
weight.

to deter any one from adopting the plan, it is but
If any valid objection can be brought forwards so as
great importance and worthy of the attention of those
right to do it, as the question of boiler priming is of
more qualified to propose a remedy than myself, for
so great an evil is much complained of by the use of
these kind of boilers.
R. D.

BOILER PRIMING.-LOCOMOTIVE DRIVING. [635] SIR,-"Bumpkin" (1. 591), suggests a plan in your last number, upon this subject, which has been under notice for some time. I do not think his way would answer, on account of the steam bubbles not being able to get away from under the wood or other material floating. If you think the following worthy of notice, I would ask you to insert it. It is a piece of sheet iron fastened above the water line in a double slanting position, as shown in the longitudinal section. No water would be able to reach the steampipe in the dome; the steam would have as free access as before, but would have to travel round between the ends of the boiler and those of the plate to roach the space above, and all water carried by it

would be deposited on the plate and run back over the end. The above is merely a suggestion.

(4859) There have been several reasons assigned for "Steam Rider's" uncomfortable ride. Mr. Tonkes appears to be nearer the mark, but the reason "Ox " gives I do not think will hold good, because the ratio of the area of the piston rod to that of the cylinder is so small as to be almost lost in the enormous pressure brought to bear upon the latter. Now I have a suggestion to make: had one side of the engine broken down leaving it running with one cylinder? I have ridden under such circumstances, and the result is a "series of jerks," as "Steam Rider" says, owing to the power being off the engine at the end of each stroke, and twice in one revolution. G. W. A.

A SUGGESTION. [636] SIR,-The suggestion of "Husband" (letter 535) is not new. The same idea was proposed to me three or four years ago, and after some trouble I succeeded id making an instrument answering all requirements. A Mr. Pratt, of America, patented and exhibited in England (about 1867) an invention for the same purpose. A description was given in the Engineer. It seemed very complicated. The first attempt of the kind was by a Frenchman, who endeavoured to make an apparatus for the use of the blind. After having made a model to test the capabilities of my plan, I was induced by an abundance of friendly advice to forego giving up time and money for "such an uncertainty," which it was asserted would not pay. ОМЕО.

THE QUADRATURE OF THE CIRCLE. [637] SIR,I am a new subscriber, and though but a self-taught working-man, I am a warm lover of science. Some few years ago, supposing that Mr. J. Smith was a sincere inquirer for truth, I wrote a letter and went about forty miles with it to endeavour to convince him of his error. He informed me he could do nothing with it that day, and that it was the old method, and so not applicable to his new method. I replied, that he ought to disprove my letter or cancel his work on the quadrature of the circle, as either the one or the other must be wrong. He has done neither.

Knowing that Mr. Smith's book has misled many of the self-taught who were not sufficiently advanced to perceive the fallacy of its circular reasoning, I have pressed the substance of my letter to Mr. Smith into the following observations, should you deem them adaped to your young mathematical readers.

I proceeded thus because Mr. Smith seemed to be well acquainted with the usual method of extracting the square root, and objected to the employment of series. The formula best adapted for computation, that I know of, is that by means of which Dr. Rutherford calculated the ratio of the circumference to the diameter to 400 places of decimals, viz.,-1 1 5

tan

-11
70

+tan

-11
99

= 4 tax (See his "Application of the Differential and Integral Calculus to find the Length of Curves.")

MOUNTING OBJECTS WITHOUT HEAT.

[638] SIR,-Will you allow me to ask Mr. W. White, of Monmouth, how he manages to mount microscopic objects in Canada balsam without heat? At p. 27, in his interesting essay on the Cricket, he says, "Don't apply heat at all whilst mounting. Never mind what the books say." Perhaps he would kindly oblige by giving us his method of mounting without heat, and wherein lies the secret. I find the balsam I use a hard resin, requiring heat before I can do anything with it. If I could use it cold I think I should not be pestered with air bubbles, &c.

I have several bottles sent me containing diatomaceæ in water. They are fit for mounting, but I am at a loss to know how to proceed, perhaps one of your talented correspondents would oblige me. They are properly prepared for mounting, but I do not know if the water should be placed on the slide and allowed to evaporate, and afterwards a glass cover cemented on them, or how to manage.

-

JOHN JAMES.

OIL FOR AIR-PUMP.-TO "INDUCTORIUM.'
[639] SIR, The oil I recommend is clock-oil,
which may be purchased in Clerkenwell at the watch
makers' tool shops. It neither dries nor corrodes,
which can soon be ascertained by examining a clock
that has been going some years.

MUNITIONS OF WAR.

M.R.C.S.

[640] SIR,-Considering the great importance and interest at present attached to our munitions of war, as well as to those of other nations, may I take the liberty of asking some of the readers of the ENGLISH MECHANIC to give a description (with sketches, perhaps) of the different forms of projectiles now used? These, I need hardly say, include Greck fire, fire-balls, smoke-balls, light-balls, parachute lights, &c., &c., as well as the inventions of Martin, Shrapnell, Palliser, Mallet, Manby, Congreve, and others, and the contrivances and fusee arrangements of Boxer, Armstrong, Pitman, &c., besides several well-known foreign in

[641] SIR,-Many thanks to Mr. Reveley (1. 551 and 1. 628) and "O. O." (1. 552) for their replies to my queries. I should like, if you are willing, to trouble them a little further, as I hardly understand their whole meaning. I can now supply other details, which would, if they had known them, perhaps have modified their opinions.

When Mr. Reveley says that the supply-pipe should be laid nearly horizontal, and that its length should be from 50ft. to 60ft., does he mean that 30ft. should be thus laid, and the other 30ft. perpendicular, like the original plan of the elder Montgolfier? Is the one or two bends thus placed in the pipe for any other purpose than merely to add to the friction of pipe and help the recoil? Any one who has ever seriously thought on the hydraulic ram must see that recoil is the principle on which it works, and that a larger quantity of water falling a short distance and checked is equal to and will raise a smaller quantity a greater height. If friction is the object, then a longer drivepipe, because it gives this, should answer the same

end.

In this case it is laid at an incline of 1 in 4, and measures about 110ft. When you put your hand on top of pipe you feel a slight recoil, but the water in cistern is quite steady and well supplied, showing there is little waste of power, and the result proves this. Its ordinary work is, for 650 gallons per hour wasted, there are 195 gallons raised, at 121 strokes per minute, or with 98 strokes per minute 390 gallons per hour are raised in a steady regular stream while the air remains. As the snift valve opens every stroke and draws apparently very well, I think we must look to occasions within the past three years it has stopped by some other cause for the absorption. On two different

ask the question, if the difficulty of regulating the air
supply is a necessary accompaniment of a high fall.
300ft. from springs which supply twenty-six gallons per
As I propose to put up another ram to raise water
minute, and where I could get a 30ft. fall, I should be
glad to have an exchange of opinion, so that I may not
make another mistake.
rams, and of what size; the best form of air cells and
valves; the size and angle of drive-pipe, and how the
joints should be made; size of rising main, and where
it should be taken off air-vessel; also, what quantity
of water I may expect to raise in twenty-four hours.
HYDRAULIC.

Should there be one or two

THE FLUTE.

[642] SIR,-Perhaps you and your readers have had enough of the flute controversy; yet I cannot refrain from saying a word in refutation of C. Devant's (1. 570) unfounded strictures upon that (if well played) sweet-toned instrument. He says the composers of the present day despise it; how is it then we find it in every orchestra ? Really the musical taste of the public must be fading, or they would not tolerate such "snorting, spitting" abortion as "C. D." has unearthed. He cannot have heard the late R. S. Pratten, Richardson, or others I could name, who have made their mark in the flute world. Again, why have poets and writers so often spoken of "flute-like voices " and tones" issuing from the lips of their heroes and heroines, if they amounted to nothing more than "tootletooing"?

a

66

I infer that our friend must hold a prejudiced opinion from having been ear-tortured by some struggling tyro on the old German flute, and not having had the treat of hearing a professor discourse upon an instrument such as Pratten's perfected, which has been a source of intense eujoyment to thousands of delighted listeners. J. H. L.

THE VIOLIN.

[643] SIR,-In looking over some back numbers of the ENGLISH MECHANIC, I found with pleasure that the subject of violin construction had excited some interest, and received much investigation, yet I did not discover that an easy manner of improving an ordinary good instrument, and therefore increasing its value, is generally known.

As I have done so to my violin with very marked success, I may speak with confidence of the improvement, which consists simply in placing a rod of light well-seasoned deal along the inside, abutting against the tail-post and the end of the neck. This bar, however, requires to be very neatly fitted and wider in the

Now it is evident to any man, except Mr. Smith, that the nearest distance between any two points is a straight line; hence the arc of any circle is longer than the chord of the same arc. It is also clear that a greater area cannot be contained in a less; therefore the area of the inscribed polygon cannot be greater than the area of the circle circumscribing the polygon. The chord of an arc is equal twice the sine of half Let a be an angle less than 45°, and radius of circle/ having too much air, but we cannot get it to repeat river to have a current of two miles an hour, find the

*1305262, which multiplied by 2 gives 2610524 for side of polygon of 24 sides or chord of 15. Multiplying by 24 we get 6.2652576 = perimeter of polygon of 24 sides. If in finding sin 15 the roots were extracted correctly to 14 places of decimals, this last result must be true to about 6 places; and, as the arc is greater than its chord, the circumference of the circle circumscribing the polygon must be greater than 6-2652576. But according to Mr. Smith's theory it would be only 6.25, which is impossible.

And finding the area of this inscribed polygon of 24 sides, it is found to be greater than what Mr. Smith declares the area of its circumscribed circle to be, which also is impossible. So Mr. Smith's theory fails. Wern Mill, Ysccifiog.

J. JONES.

this so as to regulate the supply.

Again, "O. Ö." says that a 2in. rising main is too large, because the pressure to be overcome at each pulsation of the ram is too intense. Now the pipe is taken off the air-vessel by a connection having hole through a yard or so of lin. lead pipe into 2in. main; water pressing equally in every direction, the weight in vessel will be the same with any size of pipe, and as the friction must be considerably less in a large 2in. pipe than in a small one, the larger body of water moving more slowly, the pressure in air-vessel ought to be relieved quicker, and therefore have the opposite effect to that which I suppose "O. O." to mean.

In a private inquiry I made about a ram which has a fall of 16ft. with 4in. drive-pipe, raising water 280ft. through 2in. main, about 3,000 gallons in twenty-four hours, the owner says the air-vessel holds one gallon more than is required, and should be let out every third day or twice a week.

Now too much air and no work is as bad as too little

and straining the machine. This is the reason, Mr.
Editor, why I have asked space in your valuable journal,
that we might thoroughly ventilate this practical
question. There must be some cause why, as Mr.
Reveley says, this machine is not in favour among the
public, for it certainly does all that scientific men give
it out for, and is, after gravitation, the cheapest method
of raising water. Simple as it is in theory, it requires
considerable experience to make the work satisfactory
in its details, and as a ram of low fall will go for weeks
and months without change, I am tempted again to

"A boat's crew row 3 miles down a river and back

MR. S. A. VARLEY'S PAPER.

[646] SIR,-In a paper read by Mr. S. A. Varley before the Mathematical and Physical Science Section of the British Association (a condensed report of which appears in your issue of Sept. 30th, 1870), Mr. Varley states that not a single case of a coil wire being fused has occurred on circuits protected by a bridge. Three cases, but three only, have occurred where the pointed metallic conductors have been connected together under the influence of discharge, the coils being uninjured." As this statement has been made so publicly, will you allow me, through the medium of your journal, to record the following faults in these coils which have come under my notice since the transfer of the telegraphs to the state?

In one case the coil wire was completely fused, although it was protected by a bridge. In another case the metallic conductors of the bridge were in contact, the coils being thus cut out of circuit; and in several cases the magnets outside the coils have been demagnetized, thus seriously interrupting the working, as bar magnets cannot be so readily magnatized as needles. Each case mentioned above was after a thunderstorm. As it is not at all probable that faults in these coils have been restricted to those which have come directly under my notice, it would appear that little practical advantage has been gained by their introduction, more specially as during the time to which I refer, I have no record of a serious fault, such as the above-mentioned, having occurred in the old style of coils. J. W. W.

Firstly. In a vertical mill the whole of the sails are constantly exposed to the full force of the wind. a horizontal mill it is almost impossbile for more than half the sails to operate at the same time, and most of those acting in a very imperfect manner, because they cannot all be at right angles to the wind at the same moment.

Secondly. The sails of a vertical mill have their angles varying according to their distance from the centre of motion, so that every portion of a sail does a fair amount of work. The horizontal mill has no similar arrangement, and although the sails may be said to move in a line with the wind, their velocity measured on that line is continually varying. Thirdly. The sails of a vertical mill intercept most of the wind comprised within the circle which they deseribe. A horizontal mill is entirely dependent upon the amount of sail which it can spread.

Fourthly. The sails of a vertical mill move in what may be considered as still air, though at a speed greater than the (wind. The sails of a horizontal mill have to be dragged back edge to wind at the speed of the wind the speed of the machine. It is to be remembered that the pressure of the wind is as the square of its velocity.

Lastly. The sails of a vertical mill are simple and easy to make. The sails of a horizontal one are complicated and expensive.

FRICTION OF WATER IN PIPES. [651] SIR, The question of " A Working Engineer" No. 541, on page 84, may be answered in this way. It is a law of hydraulics that the resistance of friction to water passing through a pipe of given diameter with a given velocity, increases with, and in the same ratio as, the length of the pipe. The resistance, therefore, due to the length of the pipes he mentions is as 100 to 60, or as 5 to 3. The measure of this resistance is usually called "head of water to overcome friction," and is ascertained in any particular case by the following formula. There are other formule, but this one will illustrate the case; it is given by Tredgold in his "Tracts on Hydraulics," and is quoted from Eytelwein. Let v = the velocity of the water through the pipe in feet per second.

that of the sun, hence the "Zodiacal Light," the sub-
ect of this letter.
T. A.

AN INEXPENSIVE LATHE. [653] SIR,-There have been at various times illustrations in the ENGLISH MECHANIC of lathes of varions constructions, but they have all been of a price that frightens any one, save those with a long pocket, and I are sorry to say that a long pocket seldom accompanies the love of mechanical and scientific pursuits, and makers, as a rule, either don't or won't know this. How is it that I can buy a cotton loom for £5 or £6, and any little bit of lathe costs such a lot?

Herewith I inclose a photograph of a lathe, lately purchased by a friend that lives near me, and I have often used it, and can speak well of its capabilities for both wood and iron turning.

The foot headstock is cast in one with the bed'; by this, the cone on the spindle is a good diameter, so the strap sticks well; the large speed of the cone is drilled so as to answer the purpose of a dividing plate, with

"SIGMA'S" SUGGESTION.

[654] SIR,-I think the suggestion of "Sigma's,"
in your last number, a capital idea, that the para-
doxists, the Beardsleys, the inventors of perpetual
motion, &c., should have a small space for their own
especial benefit, and as he happily styles it "come up
to be demolished" by the more intellectual and scientific
portion of our fellow subscribers. I believe such a
column would materially enhance the value of our
paper, and besides being exceedingly interesting, would
be the means of overthrowing many of the false ideas
which we often meet with. A large number of persons
that hold these erroneous views have never had their
mistakes properly pointed out, as most scientific men
think them too trivial to engage their notice; a pro-
ceeding which gives rise to a vast deal of ignorance.
Let us have it by all means.
A. SLADE.

[655] doing in

ASTRONOMICAL DIAGRAMS.
SIR,-Of all the good work Mr. Proctor is
astronomical science amongst the most useful
must be counted his exposure of the
absurdity of the diagrams generally
given in treatises on astronomy.
Stage managers would no longer
think of presenting "Othello" to an
audience in a scarlet coat, trimmed
with gold lace, a cocked hat, and a wig
with a pigtail. The artificial style of
poetry, which flourished about a century
since, is now nearly forgotten. In
landscape painting our pictures ap-
proach nearer and nearer to nature.
We are no longer presented with trees
formed of a collection of cauliflowers
tied on to broomsticks; the realm of
unreality is to be found in treatises on
astronomy-the exact science.

Can we not all remember diagrams
in which Jupiter is shown scarcely twice
the diameter of the earth, and the
earth is show as having an elliptical
orbit of suca dimensions that it seems
necessarily to be about thirty millions
of miles nearer to the sun when in
perihelion than when in aphelion?
As a contrast to this, let any one
examine Mr. Proctor's diagram of
meteor orbits. With a pair of compasses
and a rule any person without investi-
gating the subject mathematically
might, by the aid of this diagram,
thoroughly grasp the relationship which
these orbits bear to those of the bodies
in the solar systems.

What would be thought of any zoolo-
gist who treated his readers to a draw-
ing of an elephant in which that ani-
mal's eyes were represented as rather
larger than his ears, and his body twice
as long as it is high? Yet such a drawing
would be truthful compared to many
of the diagrams which are drawn for
the purpose of exemplifying astrono-
mical facts. The reason zoologists dare
not venture on such exploits, is simply
that the majority of their readers would
be able to point out the inaccuracy of
their representations. Evidently for
the very reason that the inaccuracies
are not liable to be detected, so much
the more care should be taken to avoid
them.

With Mr. Proctor's admirable ex-
ample before us of what can be done in the way of
accurate diagrams, let us protest against the further
use of such fanciful creations, and insist that those who
undertake to illustrate astronomical subjects shall-to
use Dr. Tyndall's happy phrase-make a scientific use of
their imagination.
111, Minories.

[656]

two rows of holes, 20 and 25, very useful numbers for
general work. The most prominent feature is the over-
head shaft, by this the back gear is dispensed with, the
varions changes of speed being obtained by the cones,
and large and small pulleys on end of crank and over-
head shaft. The straps are one and a half inch broad,
so there is plenty of driving power. It may be thought
that this overhead shaft will absorb a great amount of
power, but such is not the case, and it is much less
trouble to change the strap from one speed to another
than the ordinary plan in which you have to go down
on your knees and get red in the face, waste a lot of form of a
time, never naming sundry bumps and scratches, for long for
the lathe bed, &c., is much harder than skin and bone.
The photo. shows a revolving cutter in the slide-rest,
driven by means of a band pulley on overhead shaft;
and, by means of guide pulleys and swing arm turning
upon the bar below overhead shaft, the cutter can be
driven in whatever position it may be placed. This
cutter is so made as to fit it for drilling, grooving,
slotting, wheel cutting, and ornamental turning. There
is also an oval clutch made in a much stronger form
than usual, and one that will notsoon wear out, or require
repairing or get shaky as they often do. I could give
more particulars of detail, but I shall take up too much
space if I do, but the foregoing will, along with the
photo., give a good idea of the lathe and its arrange-
ments. The whole lathe is well made and all polish-
which is useless, except for makers to charge for, and
which is often but deep scratch and high polish-is
left out. It is made in a regular engineer's works,
where every appliance is to hand, and being made a
number at once can be made at a cheap rate. I have
no connection with the makers at all, I have been in a
small part of their works but once, so this letter is not
a trade puff. I simply write so that my fellow amateurs
may learn that a good cheap lathe can be had.

W. T. C.

JOHN BROWNING.

RAISING WATER (4492).
SIR,-Permit me to put this reply in the
letter, as I am afraid it will be found too
the replies to queries. Allow me first to thank
"Aquaticus" for his reply to deep-sea
soundings, and also "A. C. G." for his. I
will now fulfil the promise given so long
ago to "A. C. G." to answer his query.
His well, 285ft., is very deep, it is therefore
necessary to have something very strong
to support its own weight, and that of the
bucket of water. I shall not, therefore,
recommend any substitute for an iron
chain. The chain proposed is of the make
shown in sketch, a; it may be made very
light and strong. This chain is to pass
once over a spur wheel, the spurs holding
the chain. The wheel (not shown in the
sketch) is fixed on the axle bb (shown
broken), on one end of which is a bevel
wheel e which gears with the wheels d d,
both of which are on same hollow shaft,
which is movable along the shaft e e, but
its motion from the treadmill. The motion of c is
revolves with it. The shafte e derives
reversed by the alternate gearing of d d with c. The
shaft bb has its bearings in stanchions ff at the sides
of the well. A short distance beneath the wheel is
fitted an iron stay secured to the stanchions ff. This
stay has two arms worked on it at right angles imme-

diately beneath the working wheel. The ends of the chain, passing over the wheel, lead down through holes

PLAN

栅

in the arms of the stay, as shown by the small black squares in the plan. The upper side of these arms and of one portion of the stay (that towards the driving shaft) has a fair surface, on which slides the piece h, whose arms, i i, bear against the hollow shaft of d d There are also two arms worked on hat right angles to it, resting on the arms of the stay. The movement of

moves the wheels d d, thereby reversing the gear. What is required, therefore, is to move exactly as one bucket is emptied, thus reversing the motion, and retain it in that position until the other bucket rises to be emptied, and as that is emptied, h to return to its original position. This is accomplished as follows: -The bucket is hung on an iron rod, which has a wedge worked on the face of it, as shown at k. The chain is secured to the end of the rod, k. The large end of the wedge is in breadth equal to the necessary throw of h h, being in the position shown. As the bucket which is shown rises, the wedge will drive h across, thus moving d d. Now that h has been shifted and motion reversed it is necessary to secure h until the other bucket is empty, h is therefore secured by a pawl plate falling on its arm, which has notches to fit, the distance between the notches being equal to the throw of h. The paw! plate, which in this case secures h, is removed, and shown by itself 1, thus exposing the arm of h, on which it would fall. When his in either extreme position, there is room enough between the chain and the arm of h, to allow the thin end of the wedge to pass and lift the pawl plate before the wedge acts on h, h is driven over and the pawl plate on the opposite side falls and secures it. On the front of the bucket is a kind of handle, which as the bucket rises catches in a hook on the side of the trough, cants the bucket, and the water is carried off by the trough. I think the method is now explained in every particular, and leave it for "A. C. G." to say whether it is what the circumstances of the case require: I think it is. It is really a simple piece of mechanism that cannot well get out of order, and entirely self-acting, for when the honest donkey is put on the treadmill a bucket rises, is emptied, the motion reversed, the opposite bucket rises, is emptied, and so on continuously. The sketch is not done to any particular scale, the parts are put together as most convenient. Wishing all success to our Scientific Mutual Improvement Journal, I must conclude.-PSI.

CORRELATION OF FORCE.

[657] SIR,-As Mr. Proctor, No. 580, p. 105, requests the expression of my opinion as to the state of modern knowledge of the nature of forces, I repeat what I have often stated before; of the ultimate nature of forces, or of the causes of their operations, in fact, to use the abstract term, of their essence, our knowledge is entirely described by one word-nothing. We have not yet got over the old metaphysical stumblingblock, the question whether there really is such a thing as matter, or whether there exist actual forces. All we can deal with, all that any one will profess who really has anything beyond a very superficial, and, therefore, commonly enough, a very presumptuous knowledge, is a certain degree of information as to the external facts and operations, and a more or less wellbased idea as to the process by which these are effected.

As to heat, it is pretty certain, and the whole scientific world now admits it, that it is a "mode of motion," probably vibratory, of the atoms of matter; but no one has yet shown, or even given us a tolerably sufficient guess, as to how the externally perceptible motion of sensible heat passes into the self-contained form known as latent heat; still less does any one as yet know how (I mean by what exact process) heat is related to chemical affinity, or why the actions ascribed to affinity are always attended with gain or loss of heat. I may venture (by exercising the faculty of imagination lately and justly lauded by Tyndall) to suggest that affinity is probably a function of wave length similar to harmony in music, and may yet be traced out by mathematical considerations from the absorption effects of different bodies in the spectroscope; still it is a guess.

So with electricity. There is a very general feeling that it is also a mode of motion, but of what nature is much less certain than that of heat even. My papers originated in the desire to set forth certain ideas of stituting electricity; but supposing my theory were my own as to the nature of the mode of motion conever established, which it is not, we should still be as far as ever from knowing the cause which is at the foundation of these and other motions.

In fact, each step by which we advance the bound of our knowledge only shows us more plainly that there