poles of the planet (one of which is shown in our those dark spots, which under favourable circum- respectable opticians will supply those whose drawing) and noticed the very curious and in- stances, we see spread out as in a map over the powers of drawing are of a limited nature with teresting circumstance that the dimensions of face of Mars. These spots must be seas, and a most the means of making a very passable collection these spots agreed closely with the changes in curious and intricate system they form; while of slides at a moderate cost. It is needless to the seasons. In the year 1781, after there had the generally ochrey-red face of the planet may say that they will not for one moment endure combeen a long winter in the southern hemisphere, be held presumably to consist of rocks analogous parison with the delicately graduated outlines of the southern spot appeared of great extent, while to the red sandstones of Devonshire, or the the artiste, made under a powerful glass; neve again in 1783, after the sun had been shining on newer ones of the north-west of England; unless, theless, they are pretty, not without artistia it continuously for eight months, it seemed to be indeed, we accept the theory which has been pro- merit, and the wonder is that they can be offered very small indeed. Corresponding changes, de- pounded, that the tint of the Martial vegeta- so cheaply. Specimens have been submitted to pendent on the seasons, were discovered in the tion-instead of being like our own green-is it- me by Messrs. Barnard & Son, Oxford-street, northern spot, the conspicuous one in our en- self red. Of the actual condition of things on and Messrs. Solomons, Albemarle-street, and graving. We may, perhaps, mention, that other the planet of which we have given this brief and they were certainly excellent. The colouris light patches are seen at barren parts of the imperfect account, we forbear to speak, tempting should provide himself with the pencils, colors, planet's limb (we have ourselves, in common with as it is to theorize on the remarkable analogy erasing knife, &c., enumerated at pp. 194 other observers, noticed them on several occa- and resemblance which exists between them and 338, also the easel; I once more recommend the sions): these are probably atmospheric. Between those pertaining to our own globe. We might latter to all slide-painters, because it is easily the year 1828 and 1839 the well-known German speculate on the winds which sweep over those made, it will hold a glass of any shape firmly, and astronomers, Messrs. Beer and Mädler, observed distant continents and oceans; on the currents the footboard is a steady rest for the hand. Fa and mapped the surface of Mars with the most which flow through huge seas and narrow straits; colouring these outlines use "Medium No. 1;" unwearied assiduity; ascertaining beyond doubt, on the refreshing rain which falls on the hot and have a little turps to rinse the brush occasionally, the permanence of many of the markings. Their parched surface of Mars; on the rigour of his and proceed according to directions already given charts have since done duty in books of astro-polar winter, and the heat of the summer sun. Be careful, cleanly, patient, and persevering, sad nomy of all sorts and descriptions. We should Space however, apart from other considerations, your labour will not be in vain. I taught my add that they finally deduced 24h. 37m. 23s. for warns us that we must conclude; and so we both to draw and to paint these views; the the time of Mars' rotation. More recently, the end our series of essays on the various members much toil and disappointment I have succeeded late Captain Jacob, Mr. Nasmyth, Mr. De la Rue, of that system, in which our own world forms far beyond my expectations. This is not penned Messrs Lockyer and Phillips, and last, though by such a very insignificant unit. Originally com- as a boast, but for the encouragement of those no means least, that prince of modern observers, menced in our tenth volume (p. 119), they have who are as I once was, and who have my ward the late Rev. W. R. Dawes, F.R.S., have all con- been carried on to their conclusion in a manner, sympathy. Occasionally the lines in these tributed, in a greater or less degree to our know- which, if apparently desultory, has really had re- lines will be found somewhat heavy and rag ledge of Martial detail. Professor Phillips, F.R.S., ference to the facilities for observing the different they may be greatly improved by the employment and Mr. John Browning, F.R.A.S., have each bodies treated of. No one who has followed us of the knife, but they are apt to chip of t constructed globes of Mars; the former from the through this series of articles can possibly be more surface of the glass during the operation. is joint observations of himself and Mr. Lockyer; sensible of their shortcomings than we are, and prevent this, dip a fine sable pencil into a the latter from a chart formed by Mr. Proctor, yet we would fain hope that they may have im- mastic varnish, and draw a line upon the out B.A., F.R.A.S., from the drawings of the late Mr. parted some instruction to that numerous and in- requiring treatment, leave it for 20 minutes, and Dawes. A reduced sketch of this chart will be creasing class of amateurs who, coming into the repeat with turps, have only sufficient in t found in Proctor's book, "Other Worlds than possession of telescopes of more or less excellence, pencil to well moisten the line; in ten minst Ours." By an elaborate comparison of observa- require information at once rudimentary and pare the ragged lines smooth, and those in th tions extending over more than 200 years, Mr. accurate, as to the object on which they propose high lights thin, if needful; this should be de P. finds the length of the sidereal Martial day to to make their early essays in observation. How on the easel; but if the eye is not true, and th be accurately 24h. 37m. 22s.-735, as stated in the far we have succeeded those for whom we have hand steady, it must not be attempted. short synopsis of the elements of the planet written must judge; but, for ourselves, we should with which we commenced this article. feel repaid by the assurance that we had been Several circumstances combine to render it successful in inducing only one of our readers to certain that Mars has an atmosphere of consider- become an intelligent and earnest student of able extent. In the outset, permanent spots are those heavens which so emphatically declare never visible quite up to the planet's limb, which the glory of God, and of that firmament which appears itself luminous. Then again, these per-showeth his handiwork. manent spots are by no means always equally visible; nor does this indistinctness extend over the whole disc. This partial dimming of detail

So much for the outlines; now for the phe graphs; and here I fear I am intruding on Tiddler's ground," but not " picking up gali silver;" so I trust Tiddler & Co. will be mare when I affirm that for dissolving views I ga prefer a highly-finished hand-painted slide; a I entreat my friends to believe, that after s little experience as an exhibitor, I am strengthe in my preference by the opinion of some excellent connoisseurs. Notwithstanding, Ital

has been seen by observers of too great eminence PRACTICAL INSTRUCTIONS IN THE ART strongly with all classes of photographers.

OF DISSOLVING-VIEW PAINTING.*

No. IV.
BY SABLE.

PRINTED OUTLINES AND PHOTOGRAPHS.

and ability to admit of any doubt or question.
We have already referred to the changes in the
polar spots, which would seem, almost certainly,
to indicate that they must consist of snow; and
we may add that the late Professor Mitchell,
observing Mars in 1845, with the 13in. refractor, of
the Cincinnati Observatory, noticed spots in these HERE are doubtless many who cannot draw
polar patches which disappeared in the course of T with are dont less many who co their own
a few relatively hours. Analogous appearances, outlines, but who nevertheless possess some taste
too, have been described by Mädler, Dawes, and and skill as colourists, and desire to take a part
others. It is common in books on astronomy to in slide-painting. I regret that it is not in my
attribute the ruddy tinge of Mars to his atmo- power to afford them any great assistance,
sphere, but Dr. Huggins finds (and this is most but I will do what I can. At this stage of my
entirely in conformity with our personal ex- efforts to impart to others the little accomplish-
perience) that the clearer the atmosphere of ment which has been a never-failing source of
Mars, and the more sharply his constant detail pleasure, not merely to myself, but to all with
is defined, the redder he always appears.
whom I have had any intercourse, I beg leave
Well, then, regarding it as certain that Mars to endorse most cordially what has been advanced
has an atmosphere, the question arises, Is it at p. 293, by Mr. J. G. Crace: I would have
aqueous vapour in it which forms the cloud, or every child taught to draw as soon as he is old
interposing medium, to which the appearances enough to realize the benefit and amusement to
spoken of above are referable? This is a question himself." Drawing is an elegant and refined re-
which but a very few years since must have creation; not only pleasing but useful. Not a
been a practically insoluble one; thanks now leaf, not a feathery head of the thousand and one
though, to the spectroscope, we are able to give grasses that 'broider the fields; not a nook or
something like a definite answer to it. It was corner in the shade, not a golden spray danc-
in the early part of 1867 that this problem was ing in the mellow sunlight of the short-lived
attacked by him who has been aptly called "The autumn day; not a form or figure but has its
Herschel of the Spectroscope"-Dr. Huggins, charms for every eye; all that is lacking is the
F.R.S.—and he detected in the spectrum of Mars hand trained to reproduce them. I would have
certain dark lines, coincident with those which every child taught to draw and to swim; well
Father Secchi has shown to be referable to the taught, too, "free gratis for nothing," and every
vapour of water in our own air. It may occur adult also, if they chose. To be able to draw
here to the attentive reader that the lines observed creditably is so delightful; it enables us to pre-
by Huggins may have had their origin in our own serve such interesting memorials of what is most
atmosphere after all; but our great physicist pleasant to remember. As we turn the leaves of
guarded against this source of fallacy by turn-our sketch-book, with the snow of winter on the
ing his instrument from Mars to the Moon, which ground, and perchance (if many winters have
was shining brightly at the time, and which slipped away since the last drawing was made)
would, had the lines originated in the terrestrial with some sprinkles of white amongst our own
atmosphere, have shown them equally with Mars. locks also, we live once more the bright summer
Not one of them was visible in the lunar spec- of the happy past in the drawings before us, and
old faces and old voices again come back to us.
The printed outlines provided by most of the

trum.

And thus we find a consistent explanation of the apparent changes on the surface of the planet, of the polar snows, and of the significance of

The right of reproduction is reserved.

years ago, when I could not handle my pe deftly, I myself was a photographer, and enthusiastic; so fascinated was I that I spal neither fingers, personal or house linen, but sa ficed all to the cause; to the intense disgus the ladies who had the great misfortune interested in my belongings. For a long t encountered a series of awful failares; bet ai have a habit of sticking doggedly to that promises social enjoyment, if I once in hand, as a matter of course I was s tolerably successful (as every one mast b head, heart, and hand work well togeth first portraiture seemed to hold out o delight; but I soon lost patience with 3 that the bath, the developer, or the so often in fault as the sitter. It was chief bother lay. Often when I had really good picture, it did not please; susting was wrong about the eyes, nose, or month; In a word, it wasn't like;" so I determel "sour-looking," and the expression el devote myself exclusively to landscapes with the memorable folding camera of pa carrying my bath, solutions, glass, &, and manipulating inside the canta sleeves at the sides. Every one now hes b pet method; but with a few slight improte I would work the above against any I ha seen since. (My pictures were 10in. by S recall the old absorbing amusement sala companions in it, my heart warms tar whole brood of photographic artists. B not satisfied; the cutting sharpness of the negative always impressed my eye so I abandoned glass for French negat and it gave me what I sought. It portable, not subject to breakage; crease easily prevented; it required a longer exp that objects in motion were not so great as before, and it yielded better half shade, harmony, and other effects which are so the landscape painter, and which make a advance all this to prove that I do not random, and that I have some practial ledge of the art. The accuracy of phono

I

πάντ

is beyond all praise; that is its strength; but it is certainly wanting in half lights, more especially when reflected from all shades of green, red, &c., in the shade; that is its weakness. In colouring photographs for the lantern the artist cannot leave the blank masses of foliage and other void tracts in shadow; he must do something with them, and for my part I would rather paint ten pictures first hand than do that something. True they can be exhibited uncoloured, but to judge of the effect, place in the slide-holder of the other instrument a first-class hand-painted view, and dissolve the uncoloured photo. into it; do this before a good sprinkling of spectators, and take their verdict. This is the way in which I have arrived at my conclusions, remembering always that if I exhibited only to please my own eye, it was but a sorry pastime, but I myself like the . paintings best. I have been told that some prefer cold marble to warm flesh and blood; if this should be read by any who do, I hope they will 3. not be "werry down" upon me for declaring that I do not.

I have attempted to reproduce good engravings, mostly small ones, by the aid of photography, to avoid the labour of outlining, particularly that of reducing, but the " hatching" had a fearful effect on the screen, the picture looking as though some gigantic spider had spun his web over it. However, some tolerable photos. are sold by the houses already mentioned, and I recommend them also to the friends I am now especially addressing, Use the same colours, &c., and lay your tints lightly yet decidedly; do not attempt deep shading, but imitate the colouring of the stereoscopic pictures, and never use the knife or etching point.

To photographers I would say, with all due leference, print your positives on glass with albumen, not collodion; if you exhibit with oil, and not the oxyhydrogen light, you will soon disover the vast superiority of the former. Another objection to photos. is the protecting arnish; it greatly embarrasses the artist. I refer the freedom which the pure surface of the lass affords.

Still, for astronomical and microscopic objects, aachinery, statuary, and architectural elevations, hotography is, and must ever be, unapproachable y the hand of the draughtsman.

NOTE.-Water-colours are said to be most vailable for tinting photos. I have given the 7stem a fair and patient trial, and cannot recomend it for glass painting; but I have experiented on photos, with Judson's simple dyes, nting them as the stereoscopic pictures. This not difficult, and the result, if not acceptable to e painter's eye, is bright and pretty, albeit too osely resembling the colouring of toy books.

POTATO CULTURE. THE potato is probably the most valuable vegetable cultivated, whether regarded as a oducer of nutritious food, or as an article of ofit to the farmer. There is some doubt as to e spot in the British Isles in which it was first own as an agricultural crop; but it is generally knowledged that the first plant was raised in e garden of Sir Walter Raleigh, at Youghal, anecdote being related of his gardener, who, tasting the "apples" of the "fine American it," expressed his disappointment to his ster; and on being told to throw the weeds ay, discovered the tubers. For many years it B confined to the garden, and it was not till out 1732 that it was cultivated as a field crop Scotland. From this time it appears to have idly increased in public estimation, probably much from the improvement in its qualities to cultivation, as from its wider distribution ong the agricultural population.

871b. nearly all good-sized tubers, while the Rev. ately after hot sultry thundery weather; which
Arthur Wilkins, of Bootle, obtained 105lb. from agrees with our experience, but we think the
1lb. of cut sets. But probably the greatest weight remedy lies in lopping the tops of the haulm
ever yielded by any kind of potato has been ob- before the effects produced by the electric fluid
tained from the Bovinia, or cattle-feeder, which, have time to penetrate to the roots. Rape dust
by good manuring, produces 40 tons per acre, the has also been recommended for mixture with the
tubers being of remarkable size, single potatoes soil to prevent disease; but we imagine this is
weighing over 5lb., and measuring from 7in, to rather a palliative than a cure, as it assists in
9in. in length. Although this kind is known as opening wet and retentive ground, in which we
the cattle-feeder, it is an excellent vegetable for consider potatoes should not be planted.
table use, containing a large amount of farinaceous
matter, and keeping well for twelve months.

FIRST STEPS IN ART.

RAWLE, the head master of the Not

Various methods of cultivating the potato are practised, and numerous experiments have been tried. Thus the plan usually adopted is to dig trenches 8in. deep and 2ft. apart; about 4in. of Mtingham School of Art, spoke some very farmyard manure is placed at the bottom of each trench, and a little earth drawn down upon it or sensible words to the students at the recent annual mixed with it. The whole tubers are then meeting, on the danger of neglecting the earlier planted at intervals of a foot, but if cut sets are and more elementary stages of art education. The employed, the distance is generally reduced to study of art naturally engenders enthusiasm, and 9in., and the mould drawn over till they are the student is all too ready to trust blindly to covered 3in. deep. Another plan consists in that alone in his desire to see the fruits of his preparing the ground with a heavy coat of labours before the roots have been fairly planted. manure well dug into the surface, which is after. His faith in his own ability is sublime, and it wards raked level. The sets are then laid in lines altogether takes the place of well-grounded reon the top, and earth drawn over them, the sur-liance of the experience of others. By-and-by face being thus left in ridges. It is generally he finds that in spite of his vague longings after acknowledged that whole tubers are better than the beautiful he can produce nothing that his cut sets for planting; but while one party advises hand is altogether powerless to execute his halfthe forcing of the potatoes into growth before formed ideas, and he falls back disgusted-let us planting, another declares that this system is a hope at his own indolence, which prevented him most prolific source of disease, alleging that from acquiring those first steps in art which, whatever growth the tuber makes before it is in though tedious, and to a certain extent purely the ground, is at the expense of its own inherent mechanical, are imperatively necessary for arriving strength. at excellence.

A little work, issued by Mr. Wilkins, of To such students," said Mr. Rawle, "I would Brighton, asserts that the method of planting earnestly say be patient!' No good results can advised by the author is by far the most profit-follow work which has not been done thoroughly, able, and under proper management, will produce and, if you do, in your present state of elementary crops worth £200 per acre. knowledge, imagine that all this irksome preparatory work is unnecessary, do, I pray of you, let your own opinions be modelled by the experience of others. To do this a little faith is required. Let that faith then be given heartily, and you will find that in the end, a much greater measure of success will attend you. We must not endeavour to grasp too much at once, else we shall lose all. The surest way is the quickest way, so pray do not grudge the time and attention which is absolutely necessary for arriving at excellence, but, bear in mind that old Eastern proverb which says,

The system is briefly this :-A piece of ground, say a rod (5 square yards), is to be prepared with a liberal supply of stable manure; large whole potatoes are to be selected, from which all the eyes but one, two, or at most three, have been removed; these are to be planted 4in. deep in rows 4ft. apart each way-thus allowing 16ft. of surface to each plant. The early sorts do not require more than half this space of ground, which is necessary only for late kinds, like Regents, Shaws, Rocks, Bovinians, &c. Mr. Wilkins asserts that, grown in this manner, each plant will produce from half a bushel to a bushel! It is true that he puts in a proviso "under favourable circumstances;" but we cannot help inquiring whether a bushel from each root can really be obtained under circumstances never so favourable? Forty tons per acre have been produced as an exceptional case, with heavy manuring and the use of the Bovinia potato; but we do not believe it is the invariable result. Well, a rod of ground planted on Mr. Wilkins's system will contain seventeen plants, and allowing each to yield, as he says, the "moderate" quantity of half a bushel, the product will be eight and a half bushels, or 1360 bushels (34 tons) per acre, worth, at 3s. per bushel, the profitable sum of £204.

time and patience will change the mulberry leaf to satin.' I am perfectly aware that the first steps of art work are somewhat dull and monotonous-they are to a certain extent purely mechanical-the mind has but little real effort to make the eye has to be educated to see even the simplest objects correctly-and then the hand has to be physically trained to represent them So that all early work is simply discipline for the eye and the hand, for the higher qualities of the mind are not in any way exercised. But when a certain amount of power for representing all the varieties of form, and the subtleties of light and shade is acquired, and we come by degrees to represent nature in her beauteous and varied garb, and to use the inventive powers in producing a picture, then the mind is taxed to its fullest limits, and we enter the domains of art proper."

THE

TION.

HE annual report of the Committee of Management of this prosperous association is now before us, and is worthy of the attention of those of our readers who employ, or are in any way connected with, steam boilers. The purposes of the association are to prevent explosions by periodical examinations of the boilers belonging to members, and to afford compensation in case of accident. How well these purposes are carried out may be seen from a few statistics we proceed to quote.

Now, Mr. Mechi has proved that by sowing one grain of corn where we generally sow twenty, the yield will be quite as much; but we do not think he claims any extraordinary increase of profit by adopting this method, save what is gained by MANCHESTER STEAM USERS' ASSOCIAeconomy of seed. Mr. Wilkins, however, puts the ordinary yield of potatoes as worth £36 per acre, thus showing a difference in favour of his method of £168. We are perfectly aware that large tubers are worth considerably more per ton than small ones, and as their production forms one of the principal features of his system, which also inculcates the practice of growing early sorts between the rows of late (thus getting two crops), By careful selection of seed it has been greatly we can only say that we shall be very glad to roved of late years, the United States having hear of its successful application in the cottage en us some of the best and most prolific kinds. gardens of the poorer classes, and surely such an these probably the most valuable are the achievement (eight and a half bushels in five and limax," which stands a hot dry summer well, a half square yards) is worth the endeavour. Mr. The number of members on the 31st of last {"Bresee's Prolific " and 46 Early Rose," Wilkins says the tubers should be allowed to December was 642, and the number of boilers ch were both raised from the seed of one ball grow before planting, that they should be fre- registered 2,116. During the past year 1,988 the Garnet Chili. The Rev. C. Granger, of quently hoed, and that the haulm should be sup- "entire" examinations have been made, which, bbardton, Vermont, says he planted two rows ported by being tied to poles. He also recom-added to "internal" and "flue" examinations, Bresee's Prolific and two rows of the Garnet mends the use in addition to the ordinary manure gives a total of 2,159. The minor inspections li alongside, and found the yield of the former of a dressing of from ten to twenty bushels of stand at 4,650, making the grand total 6,809. it twice that of the latter-a convincing de- soot and salt per acre, sown broadcast before the The results of all this care is seen in the followstration of the advantages derived froi a a hoeing, a few bushels of ground chalk where the ing pregnant sentence: No explosion hus ocful raising of new strains from seed. Of the soil requires it, and the moderate employment of curred to any boiler under the inspection of the y Rose, Colonel Knatchbull, of Jersey, sewage in dry weather. Mr. Wilkins asserts that Association during the year, and consequently no that he planted 1lb. in cut sets at the the blight is as yet without cure, but says he item for compensation appears in the accounts uning of April, and obtained a yield of over has observed that it attacks the plant immedi- When we reinember that in 1870 no fewer th

Ex. 3.

References.

51 explosions occurred, killing 78 persons and in-4, timbre; 5, mental effect; of which the
juring 106 others, no comment is necessary as to representation of the first two forms the staple of
the value of the operations of the Association. A all notation. That of the third, as being borrowed
boiler is "guaranteed" only after a special and from language, is arbitrary; while the fourth and
thorough examination by the properly-qualined fifth are beside the present question. We shall
officers of the Association, which examination, now proceed to discuss these in their relative Treatment
must be repeated every twelve order.

moreover, months.

We are glad to see that the finances of the Institution are in a satisfactory condition, the revenue for the past year exceeding the expenditure by £287 10s.; the stock account and guarantee fund showing a total of £16,504.

While such a result as this report discloses can be achieved by a private association of steam users, we ask how long are the employers of steam boilers to be permitted to endanger the lives of their servants and the public? We believe that 99 per cent. of the explosions which annually recur might be prevented, and we reiterate our opinion that where boilers are not submitted to some system of periodical and effective inspection voluntarily, it should be made a matter of compulsion, or their employment prohibited by command of the Legislature.

PRACTICAL PAPERS ON HARMONY.

BY EDWIN EVANS,

FELLOW OF THE COLLEGE OF ORGANISTS.

No. 1.-THE RATIONALE OF MUSICAL NOTATION.

B

as to

Height is represented symbolically by height upon the stave* thus :-Ex. 1.

Material

Result

with the foregoing, he will find that The above diagram exhibits (a) extreme height harmony should mean the same as that and depth within the stave, (b) gradual ascent as both signify a blending or combination of t and descent; (c) sudden ascent and descent; (d) sounds. So, indeed, it does; except different heights combined; (e) simultaneous re-mony, as something more dignified, refer pose between parts; (f) simultaneous ascent and plete design rather than to the mery mechan descent; (g) ascent against descent, and v. v. ; (h) blending of two or more notes. The same ascent or descent against repose, and v. v. Thus, parison exists between the ter sale 1 although we are now crossing the threshold of arpeggio conjointly, and melody. Of c actual musical science, we are in reality only and arpeggios are melodies, as far using the power given to us by the capacity to They are melodies simply because they d represent differences of height. Before pro- come under any other head. But by a med ceeding to the consideration of the next quality of generally understand neither a mechanical ( musical sounds (viz., length or quantity) let us ing of sounds in any one direction, pause to collect what we have thus far gained. succession of them, but a beautiful d It will be noticed that in the example just given revealing a design, and seeming to spear t the notes are always employed either in its own way. The superior sense of the succession or in combination, but that, while applied to the theoretical divisions could "succession" is sometimes regular and irregular, made more apparent than by the compan "combination" is of one kind. Hence the time (length) as applied to individual te following: rhythm. Time-the time of individual does not even enter into the practical dra whereas time in the extended sense of rhy sumes an important co-equal with that d mony or melody.

Ex. 2.

References.

Material

of use........)

Results

Table.

Single Tonal Sounds.

Succession.

Scale. Arpeggio.

EFORE the subject of these papers is entered upon it is proposed to address a few words Principal modes) of encouragement to those readers who, not being musical performers, from a dread of attempting Subdivisional do. Regular. Irregular. further technical studies, from doubt their own capacity, or perchance from an idea that harmony is devoid of interest except for musical composers, hesitate to follow us. To those who are already to some extent musicians but little of an introductory nature will be necessary, except to bespeak their indulgence while matters, already known to them, are explained for the

benefit of others.

For all that remains on the subject of b as well from the elementary nature Combination. knowledge as from the abundance of the of attaining to it, we must refer the stude where; the manner, for instance, in stave is aided in the representation of the nary range of between 50 and 60 grades of terior signs, the name and situation of each sound by the use of cleffs, ledger-lines an found coincident with the following &c. This being acquired, the result

Chord.

wherein we have the origin of the three great
exemplified in such a way that the answer to the
practical divisions, scales, chords, and arpeggios
simple question-"What is a scale, chord, or
arpeggio?" is given by following the table up-
wards from the term in question. Thus, a scale
ig shown to be a regular, an arpeggio an irregular,
succession, and a chord a combination, of tonal
sounds. These practical divisions result, as has
been shown, from the simplest development of the
treatment of such sounds. Thus, a scale, chord,
or arpeggio may consist of as few as two sounds,
two being absolutely necessary to show the com-
bination, regularity, or irregularity of the pro-
gression, respectively. If extended (in the sense
of mere extension), the same terms still apply.
But when some design is exhibited, or some effect
aimed at, these terms are no longer to be con-
sidered sufficient. Moreover, as the pursuance
of a musical design frequently involves the use

Firstly, let it be well understood that the pleasure resulting from the study of music, is of two kinds the sensible and rational. The sensible pleasure is, of course, that which comes to us through the ear; the rational, through the mind. The performer, who is also a technical student of music, enjoys both of these pleasures, while the mere performer and simple student or theorist share them respectively. If it be supposed (and this is supposing the worst) that the readers of this journal are mere technical students, the rational pleasure, or that is to say the better half, still lies open to them. And if it be urged, as it may with some truth, that these two enjoy ents are of all three divisions, it is absolutely necessary to gretted, principally for the consequent loss

The exterior signs Sva. alta, and

8va. bassa (giving one octave
each way)

=14

The symbolical rendering of "length" b obtained in modern notation. This is to

in point of utility by taken into account that, of the two, the rational diversity of character. is the better cultivated separately, and is of in- the use of fermas relating to what we shall call was the length between, hot the length This difficulty is met by to deplore. The symbolical length formerly calculable service to the student who, so prepared, the use of terms to what wntra-distin. Thus the time elapsing between the per proceeds to the manipulative art. For these tion to the others. These result, not from the one note and the next was symbolized, reasons, and in order to assume as little know- application of various treatments to individual amount of time given to eachrere se ledge as possible, the notation of music will be notes, but to musical context, if we may so speak. separated by time in performance, here explained, not, as is generally the case, for There is, therefore, the same difference between by blank space in the notation, and contrariva the special behoof of those who have no other import of a word as it stands in the lexicon and differ in length.* The notation here alinded. preparation for the task than their own in- the same term beautifully employed by a master- is, of course, the Gregorian. We mentir As a matter of fact the notation of musical is same source; but there is a slight difference in representation; but before leaving it, ther hand. Of course, both have their origin from the simply in support of the principle of symbo

telligence.

easier than that of articulate sounds. The their deduction. If the student compare now still one reflection likely to be interesting to t

f. irregular groups.

1. Represent the intervals 4, 6, 9, 5 grades from 1st, 2nd, 3rd lines, treble cleff.

2. Represent the [intervals 3, 5, 8, 6 grades from 2nd, 3rd, 4th spaces, bass cleff.

3. Combine similar and oblique motion.
4. Combine contrary and oblique motion.
5. Show the point of union of the two cleffs.
6. Give the notes common to both cleffs.
7. Represent 11, 14, 2 of a semibreve.
24, 31, 3 of a minim.

8.

21, 23, 24 of a crotchet.

11. Represent

quaver.

of the great nebula.

This star being brought

towards the south edge of a large field, say of
30', a minute pair, about 10 or 11 mag., will be
seen near its centre: sweep west on the parallel
of this pair for rather more than 14°, when a
large triangle will come into the field, the p star
being 8 mag., and those at the nf and sf angles
between 9 and 10 mag. Near the centre of the
triangle the object in question will be at once re-
When last I
cognized by its flashing ruby tint.
saw it on March 1, it was beginning to outshine
the two smaller stars of the triangle, but at
Christmas it was as inconspicuous as two minute
stars, which will be found closely adjacent to it;
while, Jan. 26, 1870, it was about 9 mag. I have
not yet had time to investigate the period, but the
changes are probably not of a rapid nature.
T. W. WEBB.

E purpose in the present article to set forth the practical mode of calculating the strains upon a roof principal constructed as 1 of a semi-shown in Fig. 2. This form is preferable to that

12. Represent the value of a semibreve by 20 equal notes.

SOLAR OBSERVATION.-VARIABLE

STARS.

based upon the ordinary upright truss system,
inasmuch as the former is so detailed that the
struts are of minimum length, whereas the latter
exhibits struts of maximum length in the interior
trussing of the principal. The example here
shown may be regarded as consisting of seven
each half of the principal a secondary truss A h
trusses, namely, a primary truss A B C, and in
and the tie A h will be required to s
B, and two tertiary trusses A geei B, the condition to this horizontal strain, strains eq
struction of the principal being of course symme-
trial in regard to the central line. As in former
cases we shall deal only with one half of the
principal.

D
URING the present prevalence of great sun-
spots, frequently of sufficient magnitude to
be visible to the naked eye, the possessors of large
telescopes, who prefer avoiding a great reduction
of aperture, may attain complete safety and com-
fort by a very simple and inexpensive arrange-
ment. First, a concave lens, which for this pur-
pose will answer very nearly as well as a Barlow
combination, is to be employed to enlarge the
focal image. I have used one of about 6in. focus
with perfect success; by this means much of the
light and heat will be prevented from entering the
eye. Next, a piece of glazed visiting card, with a
hole cut in its centre about the size of a pea, or
smaller, is to be placed, with the glazed side
facing the sun, near the focus of the eyepiece. If
exactly at the focus, it will soon be destroyed;
but at a short distance from it, it will escape
combustion without losing its efficiency. The concentrated upon each of the intermediate struts
brightness of the image being thus reduced and d g, eh, fi, and a load
limited, a screen-glass which would otherwise be
speedily cracked or fused, will render observation
safe and pleasant. It would be well to shelter
the setting of the concave lens by a diaphragm of
glazed card. Of course those who wish to see
any considerable portion of the solar disc at once,
must adopt the expedient of reducing the original
aperture; but for the examination of single spots,
and areas of a few minutes in extent, I have
found this humble imitation of Dawes' eyepiece
perfectly successful, even with 9in. of silvered
glass, the heat from which on one occasion,
when the concave lens and card diaphragm were
omitted (the object being only to determine a ques-
tion of focal length), destroyed a double screen-
glass of two colours in a very few seconds. Should
plaster of Paris be at hand, a disc of that
material is quite as effective as the glazed card.

at the apex B and on the shoe or wall plate at A.
the height of the truss at the centre, let L
the total rise of the roof; that is to say
A e,
then will strain upon the different parts of the
main compression member A B be as follows:-

Some of our readers who are interested in variable stars may be glad to know that R Leonis, is at present very conspicuous, its maximum being on March 5. It is easily found by setting the telescope about half a degree (accurately 34') south of Regulus, and sweeping a few degrees to the east, when two stars of 6 or 7 mag. will come into the field, one of which (19 Leonis) is white; the other, which is the variable, showing an intense and beautiful ruddy tinge, verging, however, rather more towards orange than some And at the point A there will be a strain others of that remarkable class. I have sometimes fancied the tint of this star richer when in a less brilliant stage, and it is not improbable

that the maximum effect of colour is obtained, as

WL 4 d

WL

4 d

W L

4 d

a rule, with a moderate degree of brightness.
This variable diminishes to 10, or according to
Koch, 11 mag., with a very irregular period of The value of C will subsequently be ascertained.
about 312 days.
We must now proceed to determine the inten-

We have now completed the resolution t
strains upon the various elements of thu
of roof principal shown in Fig. 2; and
here be observed that the foregoing exa
not been selected as a special case, so
on account of its exhibiting well the meth
followed in solving the strains upon any

truss or series of trusses.

In all cases tied roofs (i.e. roofs which a at their lower extremities) exert only a vertical pressure upon the supporting was to the total load sustained by the roof.

The trusses being placed at definite dist (say r feet) apart to support a roof on total load is w lb. per square foot, and c the semi-span is S, the load upon að tú, primary truss or half principal will necessari W = w x S x I which is the value to be substituted for Wa foregoing equations when the other quanties »

known.

The strains upon each element being as tained, the sectional areas of such elements be easily determined by means of the follo

simple expressions.

Let S the strain in tons on any tie or

the strain in lb. on any tie or stra

a == the net sectional area of any t

strat in square inches.

Then with a safe load the sectional area

tensile strain will be

S
F

11200

cover another red star of variable light, less bril-dg; we find that the strain upon either fi or liant than R Leonis, but of great beauty of colour. dg will be

I have recently been fortunate enough to dis- sity of the thrusts upon the struts fi, e h, and for compressive strain the least sectional st