STELLATE HAIRS at top, and MALVA MOSCHATA. 1.10.70. wonder whether an old hand uses any of them. is about all-no, we must have a camel's-hair pencil We seldom do now, whatever we might do "years to complete our list. Now let us take one of our gone by." A piece of brass of fair thickness subjects-a male; raise the two upper coriaceous furnished with four legs is handy, but we like it wings, snip them off, put on one side; next serve better without the legs, so that we can stick it the two lower wings the same. With the forceps on blocks of wood or place it on the rings of a grip across the head near its junction retort-stand at any height above the lamp we with the thorax, and we shall see the jaws choose. But we are anticipating; we have not open and the tongue protrude. Keeping a got our slide ready for the plate yet. Our Canada firm hold with the forceps in the left hand, we balsam should not be too thick-should be in a take the scissors in the right and cut off that porglass stoppered bottle, furnished with a glass tion of the head with the jaws and tongue and rod, by which we can remove a small quantity of put it in a little vial with acetic acid. Take we the balsam as we require it and keep the store now the forceps and drag gently at the remaining free from dirt. Many like to keep their balsam portion of poor Acheta's devoted head, and we in a small syringe, from which they can expel a see make its appearance first the oesophagus dissmall quantity as they choose. This plan has tended most likely enormously with undigested many advantages. We may also have a supply victuals, and at the termination of this, a little, of diluted balsam (an ethereal solution or a solu- nearly round substance, rather larger than a pin's tion in chloroform) for use with such objects as head; this is the gizzard, which we take the sections of Sepiostaire. We shall require also liberty to snip off and pop into water. Cut off a few American clothes-clips at a few pence the feet and we have left the thorax and abdomen. per dozen, a bottle of turpentine in which to Looking carefully along one side of the latter we soak certain objects, of liquor potassa and of notice a row of bright brown dots, which are the benzole. Let us to work. spiracles. With a stroke of the scissors lengthwise on either side of these brown dots, we cut out a strip of skin, and so remove them to a bottle of liquor potass. These are all the organs we shall now attempt to dissect for mounting, with perhaps the exception of the ovipositor of the female, which, if he likes, the " 'tyro' can mount, treating it as we shall the feet. ་་ One or two correspondents have kindly given information relative to the mounting of insects. and by the kindness of one of these gentlemen the author has been able to see specimens of insects put up by their mode of treatment, and has been gratified by the highly successful results. But we must caution our readers against soaking the insect too long in strong potash, which is apt to result in producing a very transparent but very uninsect-like specimen. The preparer should always bear in mind that he does not want to make Nature's works, but to persuade Nature to show him how she has made them, and that mode of preparation is best, therefore, which least destroys the natural appearance of an object. The microscopist must place truth in the first place-to his consolation, art" always accompanies it. In mounting insects it is generally desirable to use balsam which has been thinned with chloroform or turpentine, as by this means air-bubbles are more readily got rid of. Certain parts of various insects, such as some antenne, require bleaching. For this purpose nothing is better than the following:-Hydrochloric acid, 10 drops; chlorate of potash, drachm; distilled water, loz. The antennæ may be soaked in this for a day or two, washed well, dried, and then mounted. From the shalot, or the Portugal onion, we remove the thin outer rind, carefully dry it, cut a small and perfectly square piece from it, and soak it in turpentine for a few hours. Having lighted the spirit-lamp and warmed our "table" whereon lie the slide and cover, we place the piece of "rind in the centre of the slide and put on it a small drop of balsam, and carefully lower the cover on to it and press it down as closely as possible. If nicely done no air-bubbles will be included; but if there be a few they will most likely escape if the slide be allowed to remain warm for a few hours. When finished we had better allow the slide to remain in a warm room for some days, in order that the balsam may become thoroughly set prior to our cleaning off the slide. The rind of onions, we may remark, contains very fine crystals, called raphides (from raphis, a needle). Sections of wood, of rocks, of shells, hairs of animals and plants, insects and parts of insects, may all be mounted in balsam, which, though the most troublesome, is perhaps, taking it altogether, the most valuable "medium." at bottom. If we wish to have unpapered slides we use one of Pumphrey's "vulcanites" or Collins's "tins," and neatly finish off with black varnish, by means of our Shadbolt. At the bottom of the cell we place a piece of "dead" black paper, in order that the object may stand boldly out when it is to be viewed solely as an " opaque." Some, however, and they not the least wise, mount all objects in "transparent fashion, because, say they, the diaphragm plate will always give a black ground. On the other hand, the use of the black paper gives a slide a finish, and also, we think, gives a much better background than is possible by any "well stop." From the centre of the flower of our mallow we remove the anther and its pollen, and having dried it by gentle pressure between bibulous but smooth paper, mount it in a cell in two fashions-one, on a dark ground for opaque, the other as transparent. When nicely mounted this object is very beautiful, the little pollen grains with their tiny spines looking like jewels on the exquisitelycoloured anthers. The wing of the butterfly we mount in like fashion. From the little blue Polyomnatus Aleris we remove some battledore scales, which we mount in a shallow cement cell made by aid of our Shadbolt. Care must be taken that the cell becomes nearly dry before we put on the cover, or we shall have the varnish run in. The author well remembers how in his young days he was annoyed by the mischievous freaks of his gold size, and to this day he regards that cement with considerable aversion, and generally uses Photographic black varnish" in preference. Asphalt varnish will answer excellently well for these shallow cells, and is indeed commonly used. If "rounds" and "ground edges" be used the slide must be carefully finished off with a ring of varnish round the cover, and every slide should be ticketed the moment it is covered in, whether it be papered or no. For want of this simple precaution a valuable slide will often be rendered valueless, or at best, valuable time be wasted in guessing at the name of an object. From the seed-vessels of the chickweed (Stellaria media), catchfly (Silene nutans, S. maritima, S. pendula, &c.), toadflax (Linaria cymbellaria), &c., &c., we secure most beautiful seeds for low powers. These we mount in shallow cells as opaques. Others, as the Eccremocarpus, beeorchis, Paulownia, being furnished with wings often of great beauty and delicacy, we mount as transparents. The cell should be just deep enough to allow of slight movement, and round cells had better be used. The fronds of the commonest ferns may be easily secured, and we mount them in shallow cells. In some cases (chiefly exotic) the frond of the fern is furnished with scales, which we may remove and mount dry (in balsam commonly, but not to-day). Chief of these we may mention Ctenach officinalis, Goniophlebium, and Lepicytis. Nearly all plants are furnished with hairy leaves, which may be easily mounted dry in either card cells or "rounds." Easily obtained are evergreen oak (Quercus ilex), common lavender, nettle, thistle, and in some localities the sea-buckthorn. Less easily obtainable are Deutzia scabra, Alyssum spinosa, Durio, Tillandsia, and Rhododendron Nuttali, with a host of others of almost equal beauty. Perhaps enough has been said to enable THE CRICKET AND THE MICROSCOPE. jeet readers to secure a number of "dry" ob The remainder of the week, as our space is being rapidly filled up, must be hurried over. We will learn somewhat of other media than balsam. Perhaps the better plan will be to name them in the order of their importance, as far as possible, and briefly treat of their use. H. P. To the "tyro" let us commend an hour or jects, and to mount them successfully. two's study of that well-known insect the Tuesday and Wednesday.-We may spend at cricket. Acheta domestica is its scientific name; least two days in learning to mount in balsam. it is classed amongst the Orthoptera or straight"Plague take it," said an impetuous acquaintance winged division of Insecta, of which division it is a of ours once upon a time, "I shall never learn to good type. So much for its status in insect mount in balsam, these precious (we don't think he society, now let us to our work as microscopists. meant that) air-bubbles will come for ever,' and First of all let us catch our Acheta. While we won't go. But our friend has learnt to mount, are about it, we may as well secure three or and that very successfully, and so may all our four; into the "death-bottle" they go, and while readers-with patience. Some folk when they the death-struggle goes on let us get out our post begin mounting in balsam get a lot of things-mortem instruments, which are by no means either hot-water bath, spirit-lamp, and mounting-table, numerous or costly. A tiny pair of very fineand enough things to frighten a weak-minded pointed long-shanked scissors, a pair of forceps, slide. Very good things all of them, but we some lissom fingers, a good pair of eyes, and that Now we've taken our cricket to pieces (in less time, too, than we have taken to describe it), let us begin to mount. Take up one of the first or coriaceous wings, and examine it carefully with a lens, and we find the "file" on the under side; this it is which produces the well-known song of the "Cricket on the hearth." But how? Well, we must confess we don't exactly know, but would like very much for some of the readers of the ENGLISH MECHANIC to explain. Well, one of these wings we soak in liquor potassæ a day or two, wash well with distilled water, press between two glass slips, and when dry soak in spirit of turpentine all night, and mount in balsam, file uppermost. The fellow wing we wash clean with a camel's-hair pencil and spirit of wine, and mount in its natural state (not flattened), file uppermost in a dry cell, to be viewed as an opaque object. One of the lower wings, too, we mount the same way. The gizzard we take out of the water, thrust the point of one of the blades of the scissors right through from end to end, and with a steady cut lay it open; now we tear off the exterior muscular skin, which is easily done if the gizzard has remained in water a day or so by placing it when opened between the forefinger and thumb of the left hand (skin next the forefinger), and working it (the skin) off with a blunt penknife or a needle fixed on a cork-a little practice will soon do it. We keep the gizzard wet during the operation, which makes it easier. Having succeeded in stripping the skin off we boil our gizzard in a test-tube with half and half distilled water and liquor potassa till it is perfectly clean, which we shall know by placing between two ordinary glass slips, and subjecting to in. objective under the microscope; if clean, wash out the potash, press, dry, soak in turps, and mount, as we did the first wing: if not clean, of course, we continue the boiling till it is. We may as well do two gizzards at the same time; the second we may mount as an "opaque after it has undergone the same treatment as the first, with the exception of being soaked in turps. If we examine the strip of skin containing the spiracles after a few days' maceration in the liquor potasse, we shall find most of the adhering mass separated; we use the camel's-hair pencil a little, wash well, press and dry as before, and cut off neatly a piece containing the two spiracles nearest the thorax, which are the largest, and mount in balsam after a very short stay in the turps. The feet we mount in balsam; they require rather longer soaking in turpentine. Last comes the tongue; we leave it till last, because it is most difficult, but it is easy to manage after a little practice and a few failures. We take it out of the acid (after a day or two's soaking), lay it on a clean glass slip, wash it clean with a pipette and camel's-hair pencil, arrange the jaws, &c., symmetrically, carefully place another slip over it, let it dry, and mount in balsam after a brief immersion in the turpentine bath. If in removing from the glass after drying the tongue, or, indeed, any other dissection, should be inclined to stick, we moisten it with turps, and that sets matters right. An American clothes-peg we find a good contrivance for holding the glass slips together, whilst an object is drying. A word, “ gentle tyro,” 66 as to the use of Canada balsam, and then we part. [ at night on the 17th; with Mars at 1h. 38m. a.m. on Don't apply heat at all whilst mounting, never mind what the books say. The extreme beauty of the things we have been handling has not been touched upon, that is for works on the microscope to attempt. The few practical hints here thrown together are intended to place the tyro in a position to see and admire them for himself. Yet another whisper in your ear, "gentle tyro,"don't forget to look out next week to hear how the cricket sings his song. Monmouth. THIS W. WHITE. HUGGINS & HORSNAILL'S DIAMOND MILLSTONE DRESSING MACHINE. HIS machine is very simple in construction. It consists of a bridging box and mandrel A, fixed firmly to the face of the stone. A main arm C, fitted and turning freely on the mandrel, and which is trailed true with the face of the stone by the set screws a a. The tool arm F, carrying the diamond tool h, and having a reciprocating motion given by the excentric J, lays the dress or cracks in the face of the stone in curved lines, somewhat closer at the breast than at the skirt. A click, click wheel, and worm, move the main arm round the distance of one crack to each revolution of the excentric. From the plan above described it will be seen that the machine not being, as is the case with most others, dependent on the face of the stone being true for it working properly, but the diamond being carried by the main arm, which is firmly secured true by the set screws a a a, the stones are kept straight. The machine can be worked by hand if preferred. A 4ft. stone is dressed by it in an hour and a quarter or less, thus saving both time and labour, and if worked by the mill one man could attend to more than one machine. The machine is in daily use at Bulford Mill, Braintree. HE right ascension of the sun at Greenwich THE right on on the 1st October is 12h. 19m. 45-09s. and his declination south 3° 12′ 53-2"; he is therefore situated in the constellation Virgo (map, Vol. X., p. 545), and somewhat to the west of the star @ in it. He rises in London on the 1st at 6h. 1m. a.m., and on the 31st, at 6h. 53m. a.m., setting on those days at 5h. 40m. p.m. and 4h. 34m. p.m. respectively; the length of the nights thus obviously exceeding that of the days. The equation of time is subtractive during the whole of October, and attains to a large and notable amount towards the end of the month. On the 1st, 10m. 18-69s. must be taken from the time indicated as 12 o'clock by a sundial to give the instant of mean noon; while on the 31st, 16m. 15:43s. must be subtracted from the time of apparent noon to obtain that which a properly-regulated clock should show. The moon enters her first quarter at 19m.past 9 on the night of the 1st; is full at 1h. 43m. in the afternoon of the 9th; enters her last quarter on the 17th at 6h. 1 im. p.m.; is new at 3h. 36m. p.m. on the 24th, and once more enters her first quarter at 8h. 1m. a.m. on the 31st. She is in conjunction with Jupiter at 15m. before noon on the 15th; with Uranus at half-past 10 the 20th; with Mercury at 7h. 47m. in the morning of the 23rd; with Venus at 6 o'clock on the same evening, and with Saturn at 31m. past 5 in the early morning of the 28th. The moon's age at noon on the 1st is 6-2 days; on the 2nd 7-2 days, &c. On part of her S.W. limb visible; at 6 a.m. on the 19th the 3rd, at noon, libration will render an additional the S.E. limb will come into view from the same cause; while again on the 31st, at 9 a.m., the S. W. portion of her disc will apparently increase from it also. Four occultations of fixed stars will take place this month, and upon two occasions the moon will approach so near to stars that, although she will not actually hide them when viewed from Greenwich, yet she may do so when observed from distant stations. The first occultation will be that of B. A. C. 6343, and will take place at the moon's dark limb at 6h. 41m. on the evening of the 1st, the star reappearing at the bright limb at 7h. 45m. the early morning of the 7th Aquarii will disappear at the dark limb at 1h. 42m. and reappear at the bright limb at 2h. 44m. At 11h. 20m. on the same night the moon will pass quite close to 30 Piscium. At 4h. 33m. a.m. on 15th & Tauri will be occulted by the moon's bright limb, and emerge from behind the dark limb at 5h. 55m. On the 17th, at 2h. 24m. a.m., Geminorum will disappear at the bright limb, and reappear at the dark limb at 3h. 41m. Finally, at half-past 6 in the evening of the 30th, the moon will pass so close to 4 Capricorni that (as in the case of 30 Piscium mentioned above) she may occult it as viewed from stations far removed from Greenwich. On 4 Mercury will be a morning star after the 5th; and attain his greatest western elongation at half-past in the afternoon of the 19th. He rises some hour and three-quarters before the sun, and may be well observed under these circumstances. He is in inferior conjunction with the sun at 5h. 33m. a.m. on the 4th; and will be in conjunction with Venus at 11 o'clock at night on the 11th. He is in Virgo during the whole of October. Venus is also a morning star, and approaching the sun; she is unfavourably situated for observation, and is now a small 4h. 18m. a.m. on the 1st, and about 5h. 56m. a.m. and relatively uninteresting object. She rises about at the end of the month. She sets of course, like Mercury, in daylight. She travels from the confines of Leo into Virgo. Mars is still exceedingly badly placed for observation, passing from the confines of Cancer and Leo into the latter constellation early in the month, and performing the remainder of his path in it during the rest of October; he is in conjunction with Regulus at 11h. 48m. on the night of the 30th. He rises about 48m. after midnight on the 1st, and about 29m. after it on the 31st, setting in bright sunshine. He now presents the appear ance of a rather bright and reddish fixed star, and is not worth examining telescopically. Jupiter is now coming into an excellent position for the observer. He rises on the night of the 1st about Sh. 53m., and on that of the 31st about 6h. 52m., southing at 5h. 1m. a.m., and 3h. 2m. a.m. on the succeeding mornings respectively. He is situated in the constellation Taurus during the whole of October. The phenomena of his satellites are somewhat numerous this month. On the early morning of the 2nd satellite 1 will be eclipsed at 2h. 20m. 16s., and on the night of the same day at 11h. 36m. the shadow of that satellite will enter on to the planet's limb, to be followed by the moon itself 54m. after midnight. The shadow will pass off at 1h. 50m. a.m. on the 3rd, and the satellite casting it at 3h. 9m. At 19m. after midnight on the 3rd the 1st satellite will reappear from occultation. The ingress of the shadow of satellite 2 will occur at 1h. 20m. a.m. on the 4th, and its egress at 3h. 54m., while 4m. after its shadow has left Jupiter satellite 2 will pass on to his disc. On the night of the 5th the 2nd satellite will reappear from eclipse 10h. 51m. Ss., but will be occulted some 4m. Ister by the body of the planet, from behind which it wil emerge at 1h. 31m. the next morning. On th early morning of the 8th an eclipse of satellite 3 wil take place at 1h. 22m. 53s., and its reappearance d 3h. 37m. 9s. At 4h. 13m. 43s. a.m. on the 9th satellite 1 will be eclipsed. On the 10th at 1h. 3 a.m., the shadow of the 1st satellite will enter on J piter's disc. The satellite itself will follow its shadow at 2h. 45m. The shadow will pass off at 3h. 44m, and the satellite follow it at 5 o'clock. The same satell will, in the night of the same day, be eclipsed s 10h. 42m. 4s., and will reappear from occultation & 2h. 9m. the next morning. The shadow of satente 2 will enter on to the planet's limb at 3h. 55m. O the night of the 11th the shadow of satellite I vil leave Jupiter's disc at 10h. 13m. The 3rd satellite will pass off at 10h. 49m., and the 1st satellite at 11h. 27m. An eclipse of satellite 2 will take place at 10h. 57m. 9s. at night on the 12th; it will not reappear from occultation until 4h. 1m. the next morning. Satellite 2 will pass off Jupiter's limba 10h. 15m. in the night of the 14th, while the 3rd satellite will be eclipsed at 5h. 21m. 51s. a.m. É the 15th. During the early morning of the 17 the ingress of the shadow of satellite 1 will tale place at 3h. 24m., that of the satellite itself 4h. 35m., and the egress of the shadow at 5h. The 1st satellite will be eclipsed at 12h. 35m. s on the night of the 17th, and it will reappear fre occultation at 3h. 58m. the next morning. One 18th the shadow of the 3rd satellite will pass of i 9h. 49m., and the shadow of the 1st at 9h. Satellite 1 will begin to transit Jupiter at 11 2m., and satellite 3 will come on 31. after mid off. The egress of satellite 1 itself will take pla night; 4m. later the shadow of the 1st moon will go at 1h. 17m., and that of satellite 3 at 2h. 31m. O the succeeding evening, the 19th, the 1st satellite will reappear from occultation at 10h. 25m., early next morning the 2nd will be eclipsed at 33m. 24s. On the night of the 21st a transit of satellite 2 will begin at 10h. 3m. Its shadow which will be more than ths of the way acros Jupiter's disc at the time of this entry, will pass at 10h. 21m. The satellite will follow it 39m. after midnight. At 5h. 18m. a.m. (before sunrise) on the 24th the ingress of the shadow of satellite 1 wi occur. At 2h. 29m. 11s. in the early morning of the the 25th the same satellite will disappear in eclipse and later, at 5h. 46m., reappear from occultatio behind the body of the planet itself. The night d the 25th and morning of the 26th are replete wi Jovian phenomena. At 11h. 20m. on the formu, the ingress of the shadow of satellite 3 will ta place, and at 11h. 46m. that of satellite 1. Th itself will come on 51m. after midnight. Then s 1h. 49m. a.m. on the 26th, the shadow of the satellite will pass off, and at 2h. 1m. that of the 1s The egress of satellite casting it will take place at 3h. 5m., and the ingress of satellite 3 at 3. 4h. and 20m. after that of the sha low which it cas 21st the 1st satellite will be eclipsed and reappe from occultation 13m. after midnight. The before it. At Sh. 57m. 38s. in the evening of the will be eclipsed at 4h. 9m. 33s. the next morning The shadow of satellite 1 will pass off Jupiter 27th, and at 9h. 32m. satellite 1 will follow it. O disc at half-past 8 o'clock in the evening of the the night of the 28th the ingress of the shadow d satellite 2 will take place at 10h. 20m. The satellite itself will not come on to Jupiter's disc until h 24m. At 56m. after midnight the shadow will go off, but the moon casting it will not do so until satellite 2 will reappear from occultation at lo 3h. 1m. in the morning of the 29th. On the th 3m., and finally at 16h. 22m. 52s. astronomical time on the 31st, or in civil reckoning, at 22m. 528. a.m. on the 1st of November,-the 1st satellite will disappear in eclipse. Saturn is still an evening star in October, but be is so low down, and so near to the west at sunset as to render his observation difficult. Rising so after noon at the beginning of the month, and after at sets about sh. Sum on the 1st, and about 7 o'clock on the 30th, that he must be looked for in the twilight to be caught at all; he remains on the boundary of star, and rises about 6m. past 11 on the 1st of Ophiuchus and Serpens. Uranus is an evening the month, and about 9h. 13m. at the end of it; he is just on the confines of Gemini and Cancer. Neptune is also an evening star; he remains at Somewhere about the middle of October the earth encounters no great distance from Piscium. a shower of meteors; watch should therefore kept at this period. PLATINIZING GLASS.-R. Böttger recommends the following process: Pour rosemary oil upon the dry chloride of platinum in a porcelain dish, and knead it well until all parts are moistened; then rub this up with five times its weight of lavender oil, and leave the ligand a short time to clarify. The objects to be platinized ar afterwards heated for a few minutes in a mule or over to be thinly coated with the above preparation and a Bunsen burner. ELLIS'S PATENT MACHINE FOR LAYING- also intended to produce high heat without requir WE illustrate an improved apparatus, patented parts replaceable when worn out, and B of several States, for laying-out doors, window-sashes, and work of similar character, by automatically gauging and scribing the same, so as to accurately and rapidly mark upon the stuff the places at which it is to be cut, mortised, or otherwise worked upon. In the accompanying engraving, A indicates the supporting framework of the apparatus, having at its front and upper part the fixed bed B, which is horizontal in a longitudinal direction, but, taken transversely, somewhat inclined, with its back edge the lowest, the purpose of which will presently herein appear. At one end of the bed B is the stop C, made adjustable by means of a nut and set-screw a passing through a slot in the lateral part b, by which the stop is attached to the bed. Back of the bed B, at a somewhat higher level, but parallel with the same, is the driving-shaft D, rotating in bearings e, and furnished at one end with a suitable driving-pulley E. This shaft carries any desired number of discs or heads F. These heads are attached by set-screws and grooves and feathers, or in any other suitable manner which will permit their adjustment upon the shaft at any desired distance or distances from each other, or from the stop C. For example, one of the discs being secured at the required point upon the shaft, the same setscrew f, which keeps it from sliding upon the shaft, attaches to it a slotted plate m. A second set-screw r, passing through the slot in this plate m into the hub of the adjacent disc, enables the same to be secured at any desired distance from the one first named by simply tightening the set-screw to bind the plate between the head of the screw and the hub of the discs. The other pair of discs, seen toward the opposite end of the engraving, are made adjustable in the same way. Each of the discs, furthermore, has attached to one of its sides and projecting slightly beyond its periphery a flat plate u, the thin or knifelike outer edge of which constitutes a scribe or marker. In the rotation of the iscs these markers come close to, but not in contact with, the adjacent edge of the bed B. The piece of stuff to be marked or "laid out" is placed lengthwise upon the bed, with one end gainst the stop C, the latter adjusted to bring the nearest disc and its marker at the required distance rom the end of the piece of stuff arranged as just mentioned. The piece is allowed to move in a ransverse direction upon the bed until it comes in contact with the peripheries of the discs, this movement being facilitated by the inclined position of The bed previously explained. The rotation of the iscs brings the markers against and across the djacent surface of the stuff, thereby marking the ame at the desired points. Simultaneously with his, the smooth peripheries of the discs against which the edge of the stuff is pressed during the cribing operation, serve as bearings to steady the tuff, thereby avoiding any "jumping" or irregular movement of the latter, and of course facilitating he smooth, efficient, and convenient performance f the work. GRIFFIN'S GAS FURNACE. VARIOUS forms of gas furnaces have been at that, if it fulfils its promises in general use, it will be n In full action the consumption of gas is 33ft. per hour; it melts 2lb. of iron in 70 minutes or 3 in 90. but if the furnace is hot from previous work in little more than half this time. THE USE OF SOLUTIONS OF SOLUBLE AT the meeting of the British Association, Mr. J. W. Cooper read a paper on this subject, in which he stated that in Liverpool, in 1869, Boldstreet, Church-street, and Lord-street were watered with salts during the month of July; the report of the results was very favourable, and the experiments had been continued this year. It is difficult to prove the economy resulting from the use of chloride over a limited area; and the Westminster Board of Works, after observing the effect produced at Whitehall and Knightsbridge, resolved to extend the experiment throughout their entire district, comprising an area of 250.000 square yards. As soon as the area was extended, the economy in labour and water was at once made evident. An effective method of remedying the evils arising from organic matter deposited on public thoroughfares is becoming daily a serious matter for consideration with sanitary authorities, as much sickness is believed to arise from the malaria emanating from this source. The deliquescent chloride of aluminium, recently introduced to public notice by Professor Gamgee, seems to meet all the requirements needed in the antiseptic of the future. It is non-poisonous and free from any odour; it prevents decomposition, and arrests it when commenced. It absorbs noxious gases resulting from putrefaction, and destroys parasites and germs. It is also not to be surpassed as a precipitant and deodorizer of sewage, and is only one-third the cost of carbolic acid. Mr. Cooper proposes to use this chloride for street watering, and thereby afford a means of thoroughly and effectually purifying public thoroughfares without additional cost to the ratepayers, the value of the water and labour saved being more than sufficient to pay for the necessary quantity of the chlorides. cylinder containing 16 Bunsen's burners, arranged SYSTEMS AND ENDEMIC DISEASES. the chemist's disposal for several years past, tains the crucible supported in a perforated cylinderME curious facts were brought to light on this subject at the recent meeting of the British ut where a very high heat is required, they usually Fig. 4. These parts, which are e f g in Fig. 1, are Association, where Dr. Moffat read a paper showing ecessitate a blowing machine and continuous surmounted by a cover h, which is perforated in such that the soil has an influence on the composition of abour; of this kind Mr. Griffin has introduced a manner as to deflect the flame and concentrate the cereal plants grown upon it, and on the diseases ENGLISH MECHANIC AND WORLD OF SCIENCE.-No. 288. machines, as they have been called, that have been THE ACTION OF LIGHTNING ON TELE employed at different times. I think I am correct in stating that excepting the one I wish to bring under your notice, Inches Endless Chain Grate is the only one that has received any considerable amount of approval. But although the Juckes' grate does, under favourable circumstances, prove the superiority of mechanical over hand-stoking, yet it does not, I think, sufficiently meet the engineering requirements of the present time; it has one serious defect-it is only applicable to externally-fired boilers, and is very cumbrous. mechanical stoser, to be successful, must preserve the air spaces of the fire-grate uniformly open, be A self-cleansing by discharging the ashes, slag, or clinker as formed, and in addition I think it is important that the fuel should be introduced at the front of the furnace, and have a progressive motion towards the bridge; the advantage of introducing the fuel at this part as a economy and preventing smoke where bituminous means of ensuring fuel is used, has been proved conclusively by numerous experiments. I suppose the cause of this is the long run of the volatile hydro-carbons over the incandescent fuel that fills the bridge part of the furnace. It is also important that the machine-stoker should be easily regulated and controlled for the purpose of adjusting the supply of fuel to the work to be done, and that it should be very little liable to derangement, or apparatus fulfils all these conditions. wear and tear. I think our fire-feeding machines, it is provided with a hopper or fuel receptacle, the fuel is forced into the furnace Like all by two plungers or pushers having an alternate motion-at a level of about 6in. above the bars. In very wide furnaces we use three plungers. The shaft that works the plungers is moved by a ratchet. A very simple arrangement enables the attendant to vary the rate of feed by causing the driving eccentric at each stroke to take a lesser or greater number of teeth. given to the fire by causing the bars to move forProgressive motion is ward en masse and bringing them back in detail. The cleansing of the bars is also affected by this motion; the bars have a stroke of about 3in., and we find in the average of cases that a complete stroke about every two minutes is sufficient to give the progressive motion necessary to maintain a proper thickness of fire. form an important part of the] machine, we have As the bars themselves found it necessary to make special provision for their preservation. Each movable bar is provided with a trough containing water, and there is a centre rib cast on each bar which is immersed in the water; the other part of the bar forms a perfect cover for the trough to exclude ashes, &c. These troughs are supplied with water from a small cistern, and the level is maintained by a very sensitive float and valve. motion of the machine, very little wear and tear In consequence of the slow occurs in the working parts, and there is no part of the apparatus exposed to any injurious action of fire except the upper surface of the bars, and these are effectually protected by the trough arrangement. Our experience shows that with moderate care the amount of wear and tear is not greater than what occurs in most ordinary furnaces. With regard to the economical results obtained, as compared with the best hand-firing, where ordinary fuel is used these results do not exceed ten to twelve per cent. We find that the system adopted by the careful stoker and the machine system are very similar; in both cases frequent charges at short intervals are adopted instead of heavy charges at longer intervals; but in the case of hand-firing, the incessant opening of the doors and the interruptions caused by cleaning the bars are drawbacks that are avoided in the machine. compared with ordinary random hand-firing its Of course when the machine is economical superiority is very decided, but the chief source of economy arises from our being able to use the smallest and cheapest fuel-fuel much of which cannot be used at all in ordinary hand-fire furnaces. different districts, and will range from 20 to 100 per The saving from this cause varies in cent. For many years the public have had plans constantly brought under their notice that were to end the nuisance arising from smoke; but it still continues a very substantial nuisance, and appears to have a wonderful vitality. prehension it is as well to state that we have been To prevent misapfor a period (of five or six years engaged perseveringly in efforts to perfect mechanical stoking. Our first attempts were only partially successful. Our first grate was a modified Juckes, but we soon found the wear and tear so considerable that we had to turn our attention to discover some means of remedying these very serious defects, and for more than three years we were engaged in extensive experiments involving much thought and money expenditure. The result is the machine I have the honour to bring under your notice. GRAPHS. [SEPT. 30, 1870. telegraph adoption of the lightning bridge to be decided GENERATION. проц plasm and the Germ The paper on "Proto- fluid, consisting mainly of four elements-oxygen, THEM. 13. Varley, A.I.C.E., before the Mathematical and Physical Science Section of the following is the substance of a paper read Bristol Association: by very generally used in the early days of telegraphy, but subsequently they were practically abandoned, PROTOPLASM AND THE GERM THEORY Lightning protectors were the coils, sufficient electricity passing through the destroy them, notwithstanding that the greater as the protectors adopted only occasionally saved discharge passed through the protectors direct coils when the wires were struck by lightning to THE CONTROVERSY ON SPONTANEOUS to the earth. When storms occur in the neighbourhood of telegraph wires, although the wires may not be actually struck, strong electric polarization is induced in the wires, sufficient in some cases to fuse the coils, but the effect is more often to demagnetize, netic needles used in needle telegraphs, and not inand as often to reverse the magnetism of the mag. frequently all the needle telegraphs passing through the district of the storm are again and again demagnetized, stopping the communication for a time. The destructive action of lightning is considerable and varies in different years; but the interruption it causes to telegraphs is more important than the actual destruction of apparatus; and as needle telegraphs are largely adopted by railways, on account of their simplicity, communication on these whenever storms occur. very largely employed for train signalling, and decircuits is not infrequently seriously interrupted magnetization, or the reversal of the magnetism of these instruments, is really much more serious, as Needle telegraphs are the safety of trains depends to a considerable degree ments. The increasing application of telegraphs on railways led Mr. Varley to direct his attention to on the correct working of the signalling instruthe subject with the view of producing a more effibe desired in a needle telegraph instrument are-1. cient and reliable instrument. The conditions to The mechanical portion should be simple and not liable to get out of order when subjected to rough usage. magnetization. 3. They should be efficiently protected from lightning. In 1866 Mr. Varley intro2. The needles should be incapable of deduced an instrument which he considered to fulfil the mechanical portions of the instrument, instead of most of the conditions to be desired. With respect to attaching the bearings by means of screws or bolts to wood, and making the commutator part wood and part metal, substances which could not be properly united, he constructs the instrument case, the bearings, and the anvils or resisting blocks, which have to bear the strain and concussion incidental to the working of the instrument, of cast-iron in solid piece of metal, and the contact springs can shaken loose. one solid piece, so that there are no parts to be never from their construction be submitted to more than a definite limited amount of strain. The magThe commutator barrel is also a netic needles are constructed of soft iron instead of magnetized tempered steel, and rendered inductively magnetic by permanent magnets outside the coils; consequently the demagnetizing effect of lightning on the needles is only momentary. The author protects the coils from fusion by lightning author expressed his opinion, resulting from expert by a novel protector, which he calls a "lightning ments and observations which extended over a log bridge," and it was this bridge he was more par- series of years, that those who prefer to adopt the ticularly anxious to bring before the section. Prac- theory of the creation of living forms only from tically no electricity would pass from a fifty-cell germs already in existence would eventually find pre-existing germs," the s Daniell's battery through loose powdered blacklead their view to be correct. or wood charcoal; but a current of 200 or 300 cells Dr. Bastian believes that he has not only been abs, would arrange the conducting particles by electric to create "protoplasm attraction and freely pass over, while a current of organic materials, as 600 cells would pass across a considerable interval years since by Professor Huxley, but that under From recent experiments chiefly of silica, alumina, and more or less car from inorganic materials, combined in a manner of the ordinary dust met with in rooms, consisting his hands there have been spontaneously produced bonaceous and earthy matter. by the combination of in go to show that powder opposes practically a plants and small ciliated infusoria." Mr. Samuelso was hinted possible soms decreasing resistance to an increasing tension of criticised the terms in which Dr. Bastian had deelectricity. These observations circumstantially described by him, truly “ of division, surrounding two insulated metallic vagueness. He showed how some of them were carbon and non-conducting matter in a fine state ing them as vague and giving instances of thi conductors, which approach one another within absolutely adverse to Dr. Bastian's hypothesis; ad His bridge consists of a mixture of scribed the results of his experiments, characters 1-18th of an inch, and this is placed in the most described at length a number of experiments of his direct path the lightning can take to reach the own made in June, July, and August last, compare direct path a small interval of conducting particles the plant-types (mildew or mould), believed by Dr. struck by lightning, the electric fluid meets in its him in 1863, which left little doubt on his mind that earth. When the bridge is placed in a circuit them with notes of a series of experiments tried by in close proximity to one another. united by electric attraction, and rendered incan- fusions, really spring from atmospheric gerus descent. demonstrated, offers a very free passage, and the open air upon bare rocks and stones, but which the secondary current consequently passes that way, author showed to be present in rain-water falles These are Bastian to have been spontaneously produced in inin preference to passing through the coils. The incandescent matter, as already which, in some instances, become developed in the crucial test, however, is how do they behave in the air. The result of his experiments may be thu practice? They have been in use over four years; briefly epitomised: In 1863 he found the same plant there are upwards of 1,000 doing duty in this types-various stages of mildew-in infusions of country alone; and not a single case of a coil orange-juice, cabbage-juice, and pure distilled water The from the clouds, and in distilled water exposed t wire being fused has occurred on circuits protected exposed to the air; and during the past summer be CEMENT FOR IRON AND STONE.-Glycerine and charge, the coils being uninjured. The instruments types in the atmosphere. by a bridge. Three cases, but three only, have oc- again found the identical types in infusions of litharge, stirred to a paste, hardens rapidly, and makes have made steady way. When the recent change curred where the pointed metallic conductors have orange-juice, and in water caught in a shower of a durable cement for iron upon iron, for two stone surbeen connected together under the influence of dis- rain. At both periods, too, he found lowly animal faces, and especially for fastening iron in stone. The took place in the administration of the telegraphs, the results of my experiments, which any boy poscement is insoluble, and is not attacked by strong consequent upon the Government acquiring them, sessed of a microscope may repeat as effectually as Here I leave to the judgment of men of science He concluded as follows: the Postmaster-General invited tenders for telegraph I have performed them. And if the believers in acids. versy on Spontaneous Generation, and of some rated, inasmuch as it could make but little differ recent experiments. Referring to the theological Mr. J. Samuelson gave an account of the contre type of animal and plant life is due to the dire bearing of the subject, which he believed to be over action of the physical forces on matter which has once been organized, and is undergoing decomposi tion, or to the same forces, or some modification of ence" whether the first appearance of the lowest them acting in the first instance in or upon almost? inconceivably minute organize 1 of them highly amusing. At the conclusion there spontaneous generation still insist that their hypo- Mr. Bentham, the president of the Linnæan Society, is of opinion that the experiments which have been made as to the existence or non-existence of germs cannot be taken as conclusive. The germs which float in the air cannot be seen by any microscope, and their presence or absence must be deduced from other circumstances. There is no case in which animals in their early state are visible to the microscope where it has not been proved that they have been derived from living animals. SCIENTIFIC GLEANINGS. Association.) CRANIOLOGY. Mr. F. Bridges ventured to present his audience with some observations on craniology, which we suppose is merely another name for phrenology. In the course of his remarks he created great amusement by asserting that "If the Government were only aware of the fact that a tendency to murder could be detected amongst many who were liberated from gaol, how cautious they would be in letting them loose upon society." Mr. J. Evans thought that if that course were adopted many would be removed from that honourable body, the British Association; and Dr. Duncan, as the result of a long connection with lunatics, had arrived at the conclusion that crime could as a rule be traced to the absence of education. have a share in their management. Sir John Bowring expressed an opinion that mechanics' institutes had not adapted themselves to the demands of the times, and urged that there should be more attention to modern languages. He added that an English working man, possessing a knowledge of Oriental languages, could always make his way in the East. Sir Stafford Northcote said that mechanics' institutes were established as organs of demand, but the times had changed; and it should now be their business to avail themselves of the great means of education which the Government offered. He also urged improvement in the libraries of the institutes. Mr. Rumney contended that the Lancashire mechanics' institutes had accomplished the designs of their founders; and Dr. Pankhurst, as a proof of the usefulness of the institutes, said that the first Whitworth scholar had been trained in a mechanics' institute. MIDDLE-CLASS SCHOOLS. A paper by Mr. C. H. W. Biggs, on " Middle-Class Schools as they are and as they ought to be," was read. Mr. Biggs did not complain of the number of existing schools, but that so many supplied an insufficient education. The latter was occasioned partly in consequence of some middle-class schools being so small that their proprietors could not afford to obtain the services of well-instructed masters. Another evil attending middle-class schools was that there was no guarantee that the principals or any of the masters were competent to perform the duties they undertook, or that the premises or appliances were suitable for the purpose. The present method of conducting the examinations appeared to be but incomplete, and tended to induce the pernicious habit of "cramming;" and the clever boys were pushed on to the neglect of the majority. On the existing principle, however, hardly any other course was open to the principals of such schools, for they were judged by results. meeting of the British Association, thinks A PERPETUAL CALENDAR. Success, however obtained, was the only criterion that what has been termed "atmospheric dust" is An interesting paper was presented on with the general public, who, as a rule, were guided a most important substance in connection with the petual Calendars," by Mr. Kesselmeyer, who in the selection of a school by the prizes which the sanitary condition of our towns. It has been also sent in a translation of a German calendar pupils obtained. A good system of examination demonstrated by Professor Tyndall that this of week days, or easy method for ascertaining the emanating from a competent central authority, atmospheric dust might consist of organic matter; days of the week of any given date of the Christian taking place in the school itself, and embracing but an approximate analysis offers considerable difficulty. Mr. Tichborne analyzed some dust taken that Jerusalem was destroyed on a Sunday, and be the only method, in Mr. Biggs's opinion, of meetera. Examples were given from which it appeared viva voce as well as written questions, appeared to from some of the leading streets in Dublin, and also Nero died on a Saturday. By this arrangement ing the great difficulties of the case. the precise day in the week can be ascertained of any event the date of the month and year of which DUST AS A FERMENTING AGENT. MR. B. C. TICHBORNE, in a paper read at the from the tops of the public buildings there, and is settled. A WASTE PRODUCT. "Per Mr. Thomas Rose read an important paper "On the Utilization of Fibrous Cotton-Seed," showing that a vegetable production, which should be valuable, and could be supplied to the extent of millions of tons, was now wasted. This waste product was fibrous cotton-seed, and in America alone more than a million and a half tons of the seed were wasted yearly. The seed was composed of 50 per cent. kernel, which yielded about one-third oil, and 50 per cent. huskshell with fibre adhering, of which the fibre would be one-third. His calculations was that the waste seeds would produce 250,000 tons of pure cotton, 250,000 tons of oil, and 500,000 tons of cattle cake, the value of which he estimated at £20,000,000 sterling. The husks would be taken to the paper mill and the cotton abstracted in such a manner as to form a most valuable material for paper. There was a process by which the cotton fibre could be completely separated from the shell; and the seed had a great advantage, that of unfailing supply. GRAVING-DOCK MACHINERY. Dock Machinery at the Herculaneum Dock, Liver- LETTERS TO THE EDITOR. [We do not hold ourselves responsible for the opinions 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, Tavistockstreet, Covent Garden, W.C. able to J. PASSMORE EDWARDS. "I would have every one write what he knows, and this only, but in all other subjects: For such a person as much as he knows, but no more; and that not in may have some particular knowledge and experience of the nature of such a person or such a fountain, that as 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 from 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. [428] lifted at each stroke and discharged at the lower MECHANICS' INSTITUTES. closer adherence to the original design. Mr. Renals Before we mete out our scanty tribute-for scanty it |