by a 6in. silvered glass speculum; but this can hardly be deemed as anything but an exception. Dawes says "the close pair (y) is by no means difficult object for any moderately good object glass whose aperture is sufficient to reduce the dises of the components to about 0" 60 or 0"-58 in diameter. The smallest aperture that will do this is about 7in. A somewhat smaller may so nearly separate them as to produce a dark line across the elongated and deeply-notched disc, but when the image is sufficiently quiet to admit of accurate scrutiny with a high power, a slight flattening of each disc will be perceived at the point of contact."

y Leonis is a good test-object for telescopes of about 3in. aperture. I have often seen the components distinctly divided with a 3in. O.G.

The following objects have been observed by A Mr. John Birmingham, of Tuam, who says:"Kappa Geminorum (R.A. 113h. 23m. 188., N. declination 24 54", 1820). This, which Smyth has given as a high test object, is easy to me. Webb omits it in his Cel. Obj., probably considering it too difficult for ordinary telescopes. Can the comes be variable?

"61 Ceti, R.A. 1h. 57m., S. declination 0° 58', mags. 7·11., dist. 39". I have discovered a second comes to this star; mag. 12-13, pos. 320°, dist. 60, all by estimation. As it seems to have been overlooked, Mr. Webb suggests that it may be variable. I first noticed it with 126 on a 4in. refractor, and it greatly improved with 200. Mr. Webb, who considers it pretty good work to pick it up with my telescope, sees it with 65 in his large mirror, but much better with 450.

"About 3° from 11 of Argo, and a position angle of 20°, I have observed an interesting little triangle of small stars, very close.

"8 Monocerotis, R.A. 6h. 17m., declination N. 4° 39', mags. 5.5-8., dist. 12"-9. I think I have found a second comes to this star, but have not been able to verify my observations (Jan. 14, 1870)."

Under the head of "Telescopic Work," it is hardly appropriate to refer to the observation of meteors, but as some good work may be done by amateurs without astronomical instruments in this department of the science, it may perhaps be advisable to say a few words on this subject. Observers may, by watching for these phenomena, and noting the time of their appearance, their apparent size, duration, path among the stars, colour, form, exact situation of the radiant point, and place of disappearance, considerably augment the knowledge that we already possess of these bodies. It is very seldom that on a clear evening one or more meteors are not visible; and it sometimes happens that a very brilliant one, illuminating the whole of the sky, will appear, and on its explosion leave a trail of light marking the direction and situation of its path. One of these appeared on February 13 last, and I will be described in the observations by members of the Observing Astronomical Society.

PRACTICAL INSTRUCTIONS IN THE ART
OF DISSOLVING-VIEW PAINTING.†
No III.

I

BY SABLE.

NOW proceed to dispose of the comic subjects (Figs. 3 and 4, at p. 194). Presuming, then, that the first colouring has been very evenly applied, according to the directions given at p. 338, the shading, finishing, and adjusting in the frames as slipping-slides remain to be considered. Place and secure on the easel (say Fig. 3); notice whether any of the flesh tint has been carried over the whites of the eyes; if so, it must be carefully removed by the aid of the erasing knife, Fig. 2, p. 194. Place on the palette a little crimson lake; add a little burnt umber, enough to produce a dark, ruddy flesh shade; Chin with a very little of "Medium No. 2;" and, aving determined the proper depth (not too lark) upon a trial piece of glass, commence hading the face of the first figure over the eyealls, stroking the tint off to make it lighter as approaches the eyelid; the eye will require the ame treatment on the shady side of the face. With the same tint shade the darker side of the ace; commence at the hair, carry the tint ound under the chin, and soften it as it aproaches the side in the light. Endeavour to

*Astronomical Register, 1867, p. 50. Much information ay be gleaned with reference toy and 72 Andromeda,

Com letters which are contained in this volume.
The right of reproduction is reserved.

The subject is now ready for the frame, a diagram of which is shown by Fig. 1. Length

produce a roundness of cheek by carrying the tint may also be carried round the lappets of the round it, and preserving a soft light centre, jerkin of the second figure, but delicacy of touch gradually deepening in tone towards the corner is necessary here to produce the idea of white of the upper lip and nose; repeat this on the trimming. shady side of the face, but more decidedly. The same method must be adopted round the chin, to give prominence to the under lip; also the nose, to give the effect of relief, always having respect to those parts in the deepest shadow. The lips, which must not be interfered with during the foregoing operations, may now be touched with crimson lake, to which a little burnt sienna is added, to take off the rawness of the former and impart warmth to it. The face of the second figure may now be shaded on the same principle, using burnt sienna alone for the purpose. For shading the hair of the first, employ Vandyke brown mixed with a very little lampblack, with which shade also the long shoes of the second, his pigtail, and moustache. The yellow hat, gauntlets, legs, and buckle must be carefully shaded with a mixed tint of yellow lake and burnt umber; the feather and crimson doublet with a deeper tint of crimson lake. Shade the blue dress with a deeper colouring of Prussian blue; carry a line of this down beside the dark stroke near the buttons. The belt of the other must be laid in with a mixture of lampblack and indigo; let the colour be strong, but keep it transparent, and shade with lampblack alone, avoiding opacity. Touch the white parts in the letters "glad" with a light tint of French ultramarine, and those of "you" with crimson lake; this will demand a delicate touch and a steady hand, and it concludes the second stage of the painting. The third, which is usually the last, consists in strengthening all the shadows, using the same mixtures for shading the respective colours; not laying them thicker, but judiciously strengthening by means of the darker constituents. The beauty and brilliancy of all classes of these paintings consists in giving the effect of shadow, and at the same time preserving transparency. It is quite impossible in these papers to impart all I wish, e.g., the effect of light and shade produced by the different proportions of the same colours, &c., but practice will buy experience, and industry, observation, and perseverance will lead to proficiency.

With regard to "Miss Prim" and her box of "effects," I leave them to the taste and fancy of the student. I merely suggest that a neutral grey is a good tint for shading her white frock; the sash may be laid in light blue, and when the second shading of the frock is quite dry the narrow braids at the bottom of the skirt may be lined with the same colour.

The operation of "stopping out" must now be performed. Procure a 2oz. wide-mouthed bottle, half fill with turps, and add about half an ounce of asphaltum broken into small pieces; stand this in a gentle heat for about 48 hours, and stir occasionally. When dissolved, get a square of thick glass (do not use your palette for this purpose) and place upon it half a small teaspoonful of the finest lampblack in powder; rub this into a thick cream with the solution before mentioned.

Grind it well and very smoothly; the more perfectly this is accomplished the better it will work in laying; add about five drops of pure mastic varnish, and you will have a fine black, quite impervious to the strongest light. It will require lowering to work well; this must be done with pure " turps," but be careful not to thin it too much. Secure your finished painting on the easel, and having filled a small long-haired writer's brush with the opaque black, carefully lay the colour round the figures close up to the outline; let the colour float on the glass, taking care that it does not intrude on the painting, or it will quite spoil it. The broad surface of the glass may next be filled up smoothly with a large camel-hair pencil. Turn the picture and repeat the operation on the other side, but do not carry the opaque black nearer the outline of the painting than of an inch, this will insure sufficient density. When perfectly dry (a few hours will suffice for this), place once more on the easel, and with the etching point scratch a few fine lines on each side of the feather, in the direction of the plumes, being cautious not to obliterate the outlines themselves; carry the scratches just into the opaque black, very lightly, and it will produce a good effect. Also work with the point four little clean circles within the buttons on the blue jacket, quite up to the circular outlines, and make a straight scratch down beside the dark line on the right of the buttons. When used with taste and judgment the etching point is highly effective. It

from a to a, 7 in.; width from b to b, 4in., width of woed at c gin., thickness of ditto in.; a groove must be cut to receive the painted glass; the two halves of the frame should be "keyed" together at b and a first, and when the picture is adjusted in its place the other two corners may similarly be secured. A semicircular piece should be cut out of the side at c, to enable the exhibitor to obtain a firm hold upon the slipping glass, which should be covered at d with a piece of black paper for the protection of the fingers; this glass should slip freely backwards and forwards, two narrow slips of black thin cardboard being interposed between it and the glass on which the picture is painted, in order to protect the drawing; the slipping glass must be secured by pins, as at H. I made my own frames of common mahogany, but the blank ones can be obtained very cheap with glass complete. The finished picture in the frame is next to be laid on the easel, painted side towards the operator, and the slipping glass B laid in its place and pushed in, as seen in Fig. 1; it thus serves to protect the drawing. Now trace an outline c exactly over the salutation, but a trifle larger, taking care not to encroach on the figures; turn the slip, and with a moderately full brush "stop" the part included within the outline with opaque black: leave it for a few hours to dry, and replace in the frame in proper position. Draw it briskly out and it will disclose the salute; treat the slipping glass of the other slide in the same manner, that when pushed into its place it may totally hide the interesting little girl on the trunk, and on drawing it out she will appear to start up from the box. Should the "stopping on the slip cover any part of the drawing irregularly, the black can easily be pared to the proper shape and size with the knife. The finished slide should be held up against a strong light, and should any untouched or weak places be discovered in the "stopping" the defects must be remedied.

reflector of the easel. Addenda.-Always have a good light on the

Amalgamate your mixed tints thoroughly, and prove their tone and depth on a trial piece of glass by reflected light before applying them to the subject.

Avoid heaviness, coarseness, and opacity; endeavour to keep the lights bright, and the shadows transparent, and you will seldom need to risk the spoiling of your work by varnishing. Far better retouch a picture than ruin it by heavy daubing.

In shading, keep a light hand, to avoid working up the under tints. To soften shades, press the brush between the thumb and finger, and with the broad point stroke lightly the shadows, and blend the half shades with the lights, in the second stage of painting; and the shades with the half shades in the third. Be careful to guard against all harshness in these operations.

See that the work is quite dry before commencing to shade; three days is not too long a period. In damp weather more than this is even necessary.

In shading crimson drapery, burnt sienua and umber, added to crimson lake respectively, according to the depth and richness required, produce very splendid tone.

In finishing faces, tinting the cheeks delicately with crimson lake should be performed last of all, when the shading is dry. The advanced student may use rose madder for this purpose, the medium for which is japan gold size diluted with turps.

Those who have been kind enough to give me

=

=

Wil 2

their best attention, and for themselves have used Hence the strain of the bar g e will be their best efforts, will by this time have become somewhat familiar both with detail and material, and be prepared to follow me in the more advanced paths of this truly beautiful art.

To the good editor, and all who have bestowed upon my poor efforts any interest, I most heartily offer my apology for the delay, and I beg their forgiveness; if they knew but the cause I am very sure they would not withhold it.

ELEMENTS OF ENGINEERING.-No. VIII. IRON ROOFS.-No. 3.

I pondcrticle on Iron Roofs, we now pro

N pursuance of the intention expressed in our

ceed to demonstrate the principles upon which the formulæ given in that article were based, those formulæ relating to principals of the upright truss construction as represented in the diagram (Fig. 1). The whole principal A B C may be

FIG.I B

From these complete formula the proport of any roof designed on the principle above scribed may easily be calculated; and in there be more trusses in each principal than shown in the example the processes shore merely extended will meet the exigencies 4 case. But it should be borne in mind t such calculations the smallest truss commenced with working up from that primary or main truss.

When the proportionate lengths of the el of the roof are known the formule may be gre simplified, as may be observed from a pr article (No. 2, Iron Roofs), in which he l Ah is assumed to be trisected in the po formulas. Thus, the g. When it is thought desirable the trigon cal functions may be replaced by genes

Wii

2

}

A g

e h

.

A h

the angle e Ah,

Wil

A g

1

+

Af df

and the strain on the bar e A

= {Will +

2 J A h

The tension on the bar 9 h will be
Si being strain on e h
But as shown above

analyzed into a system equivalent to five distinct trusses of the first class-the primary truss AB C, the secondary truss A e h, and the tertiary truss A dg, and truss similar to, and symmetrical with, the latter secondary and tertiary trusses situate in the half B C h of the main principal. It will be sufficient for our purpose to consider the theory of strains on one half A Bh of the principal. The load on the rafter A B will be dis- wherefore the strain on g h tributed on the points A de B in the following proportions :-Let w load per foot lineal on the rafter, then the loads will be

=

sin. n

Su x cos. m.

Determining the strain produced by this load This load will produce on B A a strain

according to the well-known principle of the parallelogram of forces, and stating the formula trigonometrically, we find

Wii A g 2 Ah

1

sin, n

Having thus determined the strains produced in each truss separately, it now remains for us to

where S the strain in compression found by sum up these strains, in order to ascertain the total the previous formula, but

strain on each element, for it must be remembered that the five trusses of the principal are not, in practice, distinct and separate from each other, but the offices of their elements are combined, so that two or more strains act upon one bar. The summarised strains will be as

assuming that A C is a horizontal straight

A correspondent gives a definition of a p girder," as follows:

A plate or solid-sided girder is disting from all others of the open or lattice sided by the fact of its sides or web consisting of a sheets or plates of iron, while the webd others is composed of upright or diagona and sometimes of both. The booms or f a plate girder have nothing whatever to do its appellation, inasmuch as they are the s and may be made in the same manner fr form of girder, whether plate or open-sided flanges of any description of girder may be h up with plates one upon another until the amount of sectional area is obtained. F ample, the Charing Cross, Blackfriars Pa bridges are open-sided girders, and the Cam street bridge, the unsightly structures sp the street close to London Bridge and Waterloo-road are plate girders. I notice, f another mistake, where the writer remarks L-iron above 24ft. in length will be charged en Will you allow me to state that I have end personally L-iron up to 40ft. in length with incurring any extra charge? I required it fr |bridge I was designing of 36ft. span; Ivided i possible, to get the angle-iron for the flanges in one length, which I found I was able to da without being charged extra for it.

IMPROVED FINDING SLIDE FOR MICROSCOPES.

A

N improved slide has been patented in this country by James L. Oliver, of Boston, U.S., and as it will probably interest our mir scopica reaucrs, we give an illustration and d

On Be=

{

Wii

1

=

2

sin.n

A

D

Wii 2

A

The invention consists in

already given.

object, or portion of an object, the exact position

of which has once been found and noted, may eadily be brought within the field when desired t any subsequent time. AA in the figure, reresent the stage of the microscope; B and C are wo plates, the lowermost of which, B, slides pon the stage, moving to and fro in a line with he direct vision of the observer, such movement being regulated by the screw a. The plate C lides upon B, and is governed by the screw b; is a pressure spring. On the upper surface of the stage A is engraved or affixed a scale c of uniform divisions, extending in front of the observer, and acting in concert with the movements of the lower slide B. A second scale d is affixed upon the upper surface of the slider D, and at right angles to the scale c. Both scales are similarly divided, and each division is equal to the diameter of the "field" of the lens of the microscope with which the scales are to operate; consequently if a field of Olin. is employed, the divisions of the scale should be Olin. Thus, a movement of either of the slides B C to the extent of 01in. will effect a like movement of the object below the lens. If the scales are graduated for the highest power employed, they will, of course, answer for any lower power. It will readily be seen that when several minute objects are mounted in a cell, any one of which it is desired to find at any time, by noting the latitude and longitude, so to speak, as represented by the scales, it can be readily brought into the field of the microscope.

PAPER MAKING.

PAPER-MAKING MACHINE.

and is boiled in caustic lye of from 1 deg. to 2 deg. for about two hours; it is then washed in either hot or cold water mixed with about 1 per cent. of sulphuric acid, in order to remove the colouring matter produced by the effect of the caustic lye. In preparing the bark of the mulberry-tree a simple water-retting will suffice when the tree is not green; or if it is desired to accelerate the process, the material may be cut in lengths of from eight to ten centimetres, and boiled for a quarter of an hour in a soda lye at half a degree, when it may be withdrawn and passed to the machine for converting it into pulp, which we illustrate in vertical section.

a trough B, formed of plates also grooved, the A is a grooved cylinder revolving on its axis o in circumference of which does not exceed that of the cylinder by more than three centimetres, and leaving between them a space which can be varied according to the nature of the substance to be treated and the state to which it is to be reduced. These plates are brought in contact with the cylinder A by means of india-rubbers c, fixed by one of their extremities to a transverse shaft a, furnished at its ends with pivots receiving rollers rolling on an inclined plane p. These indiarubbers embrace the whole of the plates, and pass over a second transverse shaft al also rolling on an inclined plane pl, and are fixed by means of levers with weights for regulating the pressure. The two inclined planes p, pl, tend to draw the extreme plates against the bars on which the india-rubbers rest. On each side of the cylinder A are placed as close as possible two cast-iron cheeks, on which are fixed parts of circular crowns of sheet-iron D, pierced with as many rectangular guides as there are plates. These guides impart to the plates B a percussion motion, and prevent vary from one to five-tenths of a millimetre is made between the plates B and the cylinder A, according as it is desired to make paper pulp or simply to extract the filaments.

parenchyma, which escapes through the interstices of the grooved plates B, and effects a partial solution of the gum in the water contained in the basin b. The matter leaves the machine by the opening N in the form of filamentous rolls, and falling on the endless cloth T1 is thence conducted to an agitator, where it is separated, and is then in a condition to be employed either in the formation of tissue (in the case of the mulberry bark) or for conversion into paper pulp. In reducing the straw at once into pulp the cylinder is completely surrounded with grooved plates; in this case the straw falls through the interstices of the plates into the lower basin b, whence it has a continuous or intermittent flow.

The bark after having been submitted to one machine for extracting the filaments, is subjected to a second, completely surrounded with grooved plates which reduces it to paste. The extraction of these latter filaments requires grooves of from four to six millimetres and one part flat of five-tenths of a millimetre at the angle. For the manufacture of pulp the grooves are from two to four millimetres, with the angles as sharp as possible.

A NEW MAGNETIC ENGINE. HE adapt the the matter to the purposes of industry has frequently been made, but hitherto without success. Now, however; the indefatigable zeal of inventors, which seemed likely to prove as fruitless in this direction as in the search for perpetual motion, has at length been rewarded-or rather it is so reported. America, the land which has given us so many inventions-good, bad, and indifferent-and which, moreover, is soon to solve the problem of world with a discovery that will revolutionize a'l our ideas of motive power. In future there will be no more steam boilers, and consequently no more explosions-even the occupation of the boiler inspectors will soon be a thing of the past, or be confined to our kitchens.

for the production of paper from straw and the bark of the mulberry-tree, for the invention of which, and of the method of preparing the raw material, letters patent have been granted to M. Gustave Demailly, of Argenteuil, France. The method is not confined to the manipulation of straw and mulberry bark, but the aloe-tree, the Agava Americana, the yucca, banana, papyrus, rush, palm, Phormium tenax, together with the bark of the osier, lime, chestnut, willow, and other trees and shrubs, as well as hemp and flax, may be treated by this method and by this apparatus. The first part of the invention relates to a chemical operation for preparing the filaments before submitting them to the mechanism for converting them into pulp.

The chemical operation is as follows:-The straw is cut into lengths of from five to six centimetres,

The modus operandi is as follows:-The matter having undergone the chemical process before mentioned is spread on the endless cloth T, and led between the grooved cylinders M M, by which it is distributed uniformly to the machine and forced to pass through the entrance r; it is then drawn along by the grooved cylinder A and reaches the first plate, which yielding to the pressure strikes the matter, which continuing to arrive is treated similarly by each blade in succession. It will be observed that the drawing movement of the cylinder A, in conjunction with the striking movement of the plates, causes the separation of the filaments and the gummy particles, destroys the

At least we presume that will be the case, for as a rule, your "steam user" has a keen eye for economy. According to the New York Telegraph Journal, an American citizen has invented an electro-motive engine (and the editor has actually seen it at work) which will induce us to re-examine all our theories of magnetic force, and, if what is stated of it be true, abolish all our steam machinery Henceforth our locomotives and our ocean steamers will take in zinc and acid as fuel, and we shall be spared the necessity of looking about for some material to supply the place of our rapidly decreas

ing coal beds. We say that it is so reported; for with all due deference to the writer of the article n the journal in question we cannot yet accept his statements as matters of fact. There is a smack of the wonderful in his account, and a great deal too much of what is know as "tall" writing. He says that "we may yet see the Atlantic crossed by huge vessels, propelled without an ounce of coal, by a power the initiative of which the captain may place beside his writing-desk in his cabin, which a child can apply, and the littlest finger may stop. The begrimed furnace-man may then come out from these lower hells, and walk the deck as clean as the passenger, and the blazing fires be put out. And it may be in the mysterious workings of the Almighty, that these electric forces, which are on every hand developing themselves as the life of the world, quickening its pulses from pole to pole, the cause of growth, and the cardinal element of a power the limit of which is yet unknown, may be ordained to remove from man part of the curse of toil, unbending the labourer's back, and making him to stand erect as at the first."

It seems then, that our "electro-motive" theorists have been seeking and looking in a wrong direction for the means of applying in an economical manner the power of the magnetic engine. They have even dar ed to assert the impossibility of using the materials at their command for the production of magnetic force at so small an expenditure as to warrant the hope of its ultimate substitution for steam. But, according to this writer, the axiom that a given electro-motive force is the exact product of a certain consumption of zinc and acid must be challenged and put to the proof. It is stated now, that although the motive force may be in the battery, yet that the magnetic power which follows its application is capable of indefinite enlargement without increase of the initiative agent. We are brought face to face also with the fact that, when a magnet is performing its maximum of work, the battery which started the magnetic power is most at rest." The writer does not pretend to explain this problem, but proceeds to tell what he has seen. At the works of Mr. H. M. Payne, Newark, New York State, is a powerful magnetic saw-mill, the "rapid and effective" action of which has been watched nine consecutive hours by independent investigators. During this time the "rapid and effective" action was kept up at an expenditure of less than lb. of zinc, at a cost of less than half a cent per hour; and it is stated that the power developed, rated at two-horse, can be maintained for 21 hours at a maximum expense of 10 cents. The battery which acted as the initiator of this remarkably economical power consisted of only four cells, and was stated to be capable of maintaining the speed and effectiveness of the machine for 60 hours without intermission and without renewal. It is also confilently asserted ti at by increasing the diameter and width of the magnets, or by multiplication of wheels and number of magnets, the power may be largely angmented without any addition to the number of cells forming the battery. It appears that this was proved by the fact that when wire of sufficient length to surround another set of magnets was added, no diminution of power was perceived, although the action of the battery was necessarily

66

less."

SELECTED ARTICLES.

STEAM BOILER EXPLOSIONS. THE Select Committee appointed to inquire into the cause of steam-boiler explosions, and as to the best means of preventing them, have published the first portion of the evidence received during the sittings which took place in the months of June and July of last year. Not being able satisfactorily to complete their investigations, they recommend that the inquiry should be resumed, and hereafter a complete report will be given of the results, with the opinions arrived at by the members upon this important subject. Of the necessity of this inquiry there can be no doubt. Taking the average of several years, it appears, on an average, that as many as 50 explosions occur every year, killing 75 persons, and injuring at least as many others. On comparing this with the loss of life consequent on railway-travelling, it appears that for every railway passenger killed from circumstances beyond his own control, three persons are killed by boiler explosions. These catastrophes have been so constant that explosions have come to be regarded as an established institution in this country-a sad but inevitable accompaniment to the use of steam.

authorities, would pay the inspectors, either by tes or by salaries. Upon an inspection the surr should send a declaration of sufficiency, stating maximum pressure which should be allowed to boiler. The Board of Trade would keep the re and grant a certificate for twelve months; a case of any person using a boiler without wa certificate, a penalty of £100 should be imp

We learn, also, from the evidence of Robertson, the details of a system of inst which he proposes should be adopted by the B of Trade; that all boilers, in the first place, be stamped and numbered, so that they mig identified; and that all boiler plates shou the maker's name on them, with the date, and a register should be kept of every boiler, so history could be traced, and if an explosions. place the name of the manufacturer should be The rest should be left to local inspectors, Board of Trade should send their officers o to see that all was working properly, and be also on coroners' inquests and inquiries me dents. The reason of the few accident i marine service (for there have been only si sions in sixteen years) he attributed as the w quence of government inspection. The Fury of the machinery being thus inspected can owners interested in the matter to take vero care to keep up the efficiency of their boilers Amongst the witnesses examined was Sir William by means of the organization at present in Fairbairn, and we gather from his evidence that, in tion, the Board of Trade, in connection consequence of the numerous accidents upon which local authorities, were quite competent to he had been called to investigate, an association had take the care of the 100,000 boilers which exs. been formed at his instigation. In the first the United Kingdom. instance, it was proposed that the millowners and After many similar opinions and s others employed in manufactures should establish elicited from other witnesses during the themselves into a voluntary society for the protection, we are not surprised to find the car. tion of property, and the lives of those who worked has sanguine hopes, by the active co-ope and lived in the vicinity of boilers and of mills the other members of the committee, L worked by steam. This suggestion was made about shall succeed in ridding the country of the p the year 1833-4; it was cordially responded to, and scourge of boiler explosions, and, at the st an association, strictly on the voluntary principle, of aiding the use of steam and the pro with certain rules and regulations, was formed. science. For a small sum per boiler, the members were not only secured from accidents by the only means applicable to the purpose, but they were guaranteed to the full value of the boiler should an explosion occur. The results have since showed that not a single life has been lost from the commencement to the present time from boilers in charge of the association, which had worked far more satisfactorily than any other insurance company. The evil chiefly arose from want of careful inspection, and had all other companies acted on the same principle boiler explosions would be almost unknown. In the opinion of Sir William Fairbairn, the government should be requested to make it compulsory for every person using a boiler to have it regularly inspected by competent authorities, leaving the responsibility of finding such to the owner. That a quarterly inspection should be made of the valves, &c., to see that these were in good working order, and a certificate to be given to that effect, and once a year an inspection should be made both of the exterior and interior; in other words, a thorough inspection of every part of the boiler. All that would be required from the government would be to enact a law that every person having a boiler should be bound to have it inspected by some competent au thority-either an association or an insurance company. No unregistered association should be considered competent; and when a boiler had been declined or condemned--which is not the case at present-it should be made imperative that the boiler should cease to be used.

Upon the subject of legislative interference, Capt. R. Robertson, R.N., the Surveyor-general of steam vessels under the Board of Trade, was examined, and we learn from the evidence given, that in his estimation all boilers should be inspected once a year, and a certificate given with regard to sufficiency; the inspection to be carried out by competent surveyors, and that local bodies in different parts of the country should appoint inspectors for the locality, subject to the approval of the Board of Trade, or some other public department; that such department should have the power of removing any incompetent person, or for any other cause; they should be appointed in the same way as the boards of guardians appoint medical officers and others, subject to the approval of the Poor Law Board, and as the local marine boards appoint examiners in navigation and others under the Board of Trade; that is to say, that the different local authorities should ascertain the number of inspectors necessary for their respective districts, and should select proper men and nominate them to the Board of Trade for approval. That every new boiler before it leaves the works of the maker should be inspected by a surveyor, who should examine it under the direction of the Board of Trade, and should see that it is properly constructed, with all the necessary appliances, such as steam-gauges, safety valves, &c.; that the owner of the boiler should not be relieved from any responsibility in consequence, because, in event of an accident, the jury would probably take this into consideration in awarding damages. That a fee should be charged upon every survey, which should be paid to the local authori ties, and then the Board of Trade, or the locall

BURROWING INSECTS."

MANY of the orthopterous les th themselves reside, or preparing a sub rowers, either digging holes wheret habitation for their young.

The best-known and most important insects is the mole cricket (Gryllotalpa called in some places the croaker, or che on account of the peculiar sound which it p It is a truly wonderful insect, one of those *_* which, for the sake of force, we may pers the anomalies of nature, though, in fact, La perfectly harmonious, and can have no real lies. A cursory glance at the insect w point out its habits, for the general shape, as the strange development of the fore-m the peculiar formation of the first pair of i so similar to the corresponding members mole that the identity of their pursuits is evident.

Like the mole, the insect passes a whole of its life underground, digging passages by means of its spade-like traversing them with some swiftness. L mole, it is fierce and quarrelsome, is even fight with its kind, and if victorious, alw to pieces its vanquished opponent. Like it is exceedingly voracious, and requires food, that if several of them be confined in cage and kept only for a short time wit the strongest will fall upon the weakest, devour them.

always burrows to some considerable de To procure the insect is no easy matter, f the soil is so loose, and a labourer with would find much difficulty in disinterring recognized method of procuring these in mark their holes by day and to visit them just when the insects, which are noctur habits, are beginning to be lively. A long grass-blade is then pushed into the hale is grasped in the jaws of the offended and both grass-blade and mole cricket are out together.

Just as the mole constructs a habitation from its ordinary galleries, so does this se a chamber for domestic purposes apart tis tunnels which ramify in so many direction the surface of the ground a really large cha constructed, measuring about three inches meter, and nearly lin. in height. It is m neatly, and the walls are carefully Within this chamber the mole cricket dep eggs, which are generally from two hundred in number, and yellowish in c the chamber lies so near the surface of the the genial sunbeams are able to raise the ture sufficient for the hatching of the eggs in due course of time produce the tiny yea white creatures, very like the parent in sh cept that they have no wings. They do no the perfect state until the third year. The black-bodied field cricket (Acheta campa

*From "Strange Dwellings," by the Rev. J. G. Wi