Fig. 1 enlarged (22 kB)

Having cut the exact size, next proceed to make on it, in pencil, the plan as detailed in Fig. 1, as follows: Rule the two parallel lines A E, B F, at distances of a quarter of an inch and three-eighths of an inch respectively from one edge; rule C G, D H at the same distances respectively from the other edge. Next measure off from one end (which you had better mark ‘Front’) half an inch, then one inch and a quarter, one inch, one inch and three-quarters, etc., as on plan (this must be done on both edges); rule lines across where the words ‘RAISE UP,’ 1, 2, 3, 4, are marked. The shaded parts between the parallel lines should be shaded on your plan as in the diagram. These shaded parts are now to be cut out with a sharp knife. It requires both patience and care to prevent the wood splitting, but a little practice will enable you to do this easily and skilfully. These cut-out spaces (as will be seen afterwards) are for the wheels.

The foundation is now prepared, and the next process is to cut out four boiler ends, or ‘Raise-ups,’ as they are termed, 1 and 2 for the front, 3 and 4 for the back of boiler. They are all different, and are formed as follows: On four pieces of thick card (No. 2a in list of materials) describe circles with radius one and one-eighth of an inch (equal to half the distance from A D); in Nos. 2 and 3 describe a second circle, with radius not quite a quarter of an inch less.

Nos. 1, 2, 3, and 4 must each have a base-line two inches and a quarter long. The ends of Nos. 1 and 2 must curve up to meet the circle, and Nos. 3 and 4 are perpendicular lines from ends of base line to meet the circle (as shown above in Fig. 2). Now place these on your cutting-board (No. 14 in list of materials) and with a very sharp knife cut them neatly and carefully the required shapes. Nos. 1 and 4 must be left quite whole in the centre; Nos. 2 and 3 must have their centres cut out round the inner circle. (In cutting do not try to make a continuous cut, or your knife is almost certain to slip and spoil your work; do it by successive ‘digs’ with the point of the knife, in the manner adopted by a gardener when cutting round the edges of a flower-bed with his spade.)

We are now in a position to make the body of the boiler. For this, take a piece of thin card (2c in list); it should be seven inches long (the length from K to L in Fig. 1), and about eight inches and a half wide. This must be rolled into a cylinder, and is then ready for fitting into the ‘raise-ups’ 2 and 3. No. 1 is then placed at the front end and gummed on, and No. 4 at the other end and also gummed on. No. 2 should be one and three-eighths of an inch from No. 1, and No. 3 be one and seven-eighths of an inch from No. 4. These ‘raise-ups’ should now all be fixed in their places on the foundation, and fastened at the bottom edge with the thick solution of gum (No. 3 in list), being held firmly to the foundation by elastic bands (No. 6 in list). These bands must not be too strong or they will flatten the boiler. In all gumming, pins should be freely stuck round to hold the parts in the desired position until they are dry. Our model will now present this appearance. The short perpendicular lines with knobs marked a represent pins; the lines marked b represent elastic bands.

When this is firmly stuck, two other pieces of thin card should be prepared to connect the ‘raise-ups.’ One must be one and three-eighths of an inch wide, and the other one and seven-eighths of an inch, and long enough to reach from the ‘foundation’ on one side, over the top, to the ‘foundation’ again on the other side. They must exactly follow the shapes of the ‘raise-ups,’ and should be cut to exactly fit, but not before the previous work is quite dry and firm. When prepared, gum in position; they are called ‘over-raise-ups.’ Several folds of cotton must be wound round the part marked a b c d to hold it while drying.

The next process is to well coat it with paint of the desired colour. If we are copying one of the South-Eastern Railway Company’s engines, the body will have to be painted ‘chrome-green’; if one of the Brighton Company’s, it will have to be painted ‘yellow-ochre.’ As the latter is liable to become soiled, we will select the former, and commence by mixing our colour. We shall require two penny cakes (No. 4 in list of materials). They should be placed in a small tin or earthenware pot (one of Liebig’s extract-of-beef pots answers the purpose admirably), a little water is then added, and one of your cakes may easily be softened with a large paint-brush (No. 5 in list). Make your colour of the consistency of cream, so that it works freely. It may be mixed while the previous work is drying. When all is ready, paint the boiler and ‘over-raise-ups’ evenly with it, and let it dry; a second coat is applied in the same way, and usually a third and fourth coat. The front and back ‘raise-ups’ (Nos. 1 and 4) are not painted chrome-green. The body being evenly painted, and dry, we proceed to ornament the boiler with some fine lines; these are made by cutting with a sharp knife eight narrow strips of paper, the exact width being, of course, very much a matter of taste. You will require a ruler to guide your knife, and you must place your paper on something smooth and very hard (not wood) while you cut, or the paper will curl up. These strips must be about nine or ten inches long. Six are to be painted black and two vermilion; immediately after painting them, just shift their position a little or the edges will stick to the material on which they are laid, and they will break when you attempt to lift them after they are dry. When dry, place them as follows: First take a black strip, gum it, and stick it exactly midway between raise-ups (Nos. 2 and 3) quite round the boiler; on each side of this, and about three-eighths of an inch distant from it, gum a vermilion strip; next gum and place two black strips similarly, one on each side, about an inch and a half distant from the centre strip. The three remaining black strips are to be thus placed: one at the front edge of the front ‘over-raise-up,’ a second at the back edge of the same, the third at the front of the back ‘over-raise-up;’ the three last will then be exactly over the raise-ups Nos. 1, 2, and 3. We now require two strips of card the exact length of the space between Nos. 2 and 3 ‘raise-ups,’ and not quite half an inch wide; paint them well over with ‘chrome-green’ like the boiler, and when dry edge with a black line, using the smallest paint-brush for this black line. These are to be gummed at the lower side of the boiler touching the foundation, and meeting the boiler obliquely, thus:— model. The position of the strips is shown at a. In all gumming use plenty of gum, but let the greater part be on the side hid from view.

Fig. 5 enlarged (14 kB)

We have now to construct ‘side-boxes.’ Take a piece of medium thickness card (a used white postcard), and make it the shape of Fig. 5. Where the dotted lines come, cut a little V-shaped groove, not quite through the card, like this:— model. And by bringing the two edges of the groove together, thus, model, you will be enabled to fold the card at right angles at those places without breaking it. Having cut this as required, it must be folded and gummed into shape (put plenty of gum into the joints and corners), and kept in this position on a piece of wood by pins. Fig. 6 shows its appearance.

Make another similar to this for the other side; the same shaped card will do, all that you need alter is the V groove, which must be on the reverse side of the card to enable you to fold it so as to make a pair—right and left-handed. When dry, paint ‘chrome-green,’ edge with black, and gum in position one on each side of the back ‘over-raise-up,’ to which they should exactly fit. Fig. 8 shows them in position marked b. The next thing to do is to make ‘MIDDLE-BOXES.’ They are two in number, and are placed, one on each side, exactly in the middle of the boiler, as marked a in Fig. 8. Medium thickness is required. Describe a circle, with radius one inch; within and concentric describe a second with radius seven-eighths of an inch, and a third concentric with radius three-eighths of an inch; divide this into two equal parts by the line A B, Fig. 7. Between the two inner circles draw radiating spokes, as in Fig. 7. Cut out the shaded parts neatly with a sharp knife. Cut through the line A B to divide into two parts. Now prepare two pieces of card shaped something like Fig. 5a; and the length must be sufficient to reach from A to B round the outer circle in Fig. 7, the curve being made to fit nicely to the boiler, as marked c in Fig. 8. Gum these to the middle-boxes, and, when dry, paint ‘chrome-green,’ edged with black; gum middle-boxes in their places on the boiler. In the centre of the front ‘raise-up’ gum a circular piece of thin card (radius three-quarters of an inch)—this represents soot-door; a pin, with head and point cut off, gummed on the left side with two narrow strips of card from the pin to beyond the circle as annexed will form the hinges; two other pieces of pin, as shown on the side opposite to the hinges, form the handles.

The soot-door should be painted black.

The model should now present the appearance of Fig. 8.

We have next to make a ‘DOME-BOX’ and a FUNNEL-BOX. As both of these are alike except in size, we will give details of the first, and dimensions only of the second. On a piece of ‘medium’ card construct a square with sides one and a half inch long, construct a second within it with sides one inch long, cut out the corners shaded, leave the sides A B and C D straight, but curve, as shown, the lines marked E F and G H, so that they fit the boiler; the annexed (Fig. 9, No. 1) is full size and exactly the shape. All round the inner square, where the dotted lines are shown, a V-shaped groove must be cut, as when making ‘side-boxes’: fold in, gum well in at the angles, and place pins round to keep it in position until dry, as at Fig. 9, No. 2.

The dimensions of the ‘funnel-box’ are: outer square, one and a quarter inches sides; inner square, three-quarters of an inch sides. The ‘dome-box’ is to be painted chrome-green and edged with black; the ‘funnel-box’ is to be painted black. When they are quite dry they must be gummed in position; the ‘dome-box’ is to be placed on the boiler, almost in the centre, but slightly nearer the front than the back; the ‘funnel-box’ exactly in the centre of the front over ‘raise-up.’

Now obtain a piece of deal about six inches long and rather more than an inch square; the corners are to be cut away at one end, so that the end is shaped something like a glass shade; then with sand-paper (coarse first and then fine) the rounded part is smoothed; cut it off square, about one inch and a quarter from the rounded end, as shown at A B.

This is the ‘DOME,’ and if it be gilded with a little of Judson’s or Bessemer’s gold paint, it adds much to the appearance; when gilded and dry, stick it on the ‘dome-box;’ it should exactly reach the centre of each side of the square; looked at from above, it appears as at a; looked at from one side, it appears as at b.

Next take a piece of rather stout note-paper, about six inches long and half an inch wide, roll it round a piece of slate-pencil several times, gum the outer end, and when dry slip it off; cut a circular piece of medium card to fit the end, which should be about half an inch in diameter; now roll another piece of paper about a quarter of an inch wide so as to make a roll about a third of the diameter of the preceding, gum the outer end as before, and fix it in the centre of the circular card; cut a second disc of card with the centre cut out just to fit on the top of the small roll; it will then appear thus: It is called the ‘steam-funnel’; it is to be painted ‘chrome-green’ and edged with black; its position is the centre of the back ‘over-raise-up.’

We must now make our screen. For this we require a piece of thick card three and a half inches long and two and five-eighths inches wide. It is to be of the shape here given, but the width must be such that it will fit tightly in between the side-boxes (see b, Fig. 8) at the rear end of the boiler; the top must reach about half an inch higher than the steam-funnel and be rounded at the corners. In this two circular holes of about three-quarters of an inch in diameter must be cut; their position is half an inch below the top and a quarter of an inch from the sides; paint it chrome-green and edge with black. If pieces of circular glass, such as are used for covering objects when mounted for the microscope, were placed over the circular holes, and gilded round the edges, they would improve the appearance; they are not essential. On this screen we now provide a circular piece of thin card of the same diameter as the large end of boiler—viz., two and a quarter inches; this must be painted black, and is then gummed on the screen so as to correspond with the boiler end when the screen is in position; a hole, horizontal at the top and circular below, of this shape and dimensions must now be cut through both cards for an ash-pan, the lower edge being about one-eighth of an inch from the edge of the circle; at the back, over the hole, gum a piece of paper painted vermilion, and dotted with black to represent fallen cinders.

On this boiler end must now be made furnace and furnace-door. For this take a piece of ‘medium’ card, and on it describe a semi-circle, with diameter one and three-quarter inches. In this make a door shaped as in the diagram, cut quite through the part marked a, b, c, d, except where the dotted line comes. Where this dotted line is shown it should be cut on the reverse side of the card, half through the card. This is the door, and it will then stand partly open. Round the circular part gum a piece of thin card, one-eighth of an inch wide. Fasten down with pins as before to dry, as annexed. When dry, paint the part which is to show outside black, and stick a piece of paper painted vermilion on the inner side of door. The vermilion should show through the partly open door, in order to give the ruddy appearance of fire. This furnace end may now be gummed on the boiler end (see Fig. 11). When in position the bottom will be parallel with the top of the ‘ash-pan’ opening, and about one eighth of an inch above it. It will stand out from the boiler end. Now with a large pin make holes all round the edge of the boiler end. They should be close together, like this: model. In these holes insert pins, with the heads showing outside, and this will give the effect of bright rivets.

Next take a piece of medium card, and make it of this size and shape: As seen from front.. Where the dotted lines marked ‘1’ are shown, bend it at right angles from you; where the dotted lines marked ‘2’ are shown, bend at right angles outwards; it will, when looked at edgeways, appear like this: As seen from above.. Paint it black on both sides, and gum the ends (2 to 3) on the screen just above the boiler end. The lever (4, 5) is to work in this on its centre (4). A narrow piece of thick card, about one inch and a quarter long, will do for the lever, while a pin inserted at 4 forms the centre on which it moves.

We then fix our ‘steam-gauge.’ It consists of a circular piece of white medium card, on which is shown the numbers 10, 20, 30, 40, etc., to indicate the pressure. A pin through the centre connects it with the steam-funnel. The pin represents the steam-pipe. We now require taps, which we make out of pins, by cutting off the heads and bending them at right angles about one-eighth of an inch from the headless end. The point is pushed through the card, leaving outside about one-eighth of an inch in addition to the bent part, as shown in accompanying cut. Above this we gum another piece of bent pin this size model and shape, for handle of tap. Two or three of these should be placed on the boiler end, at the left side above the furnace.

Our screen will now appear as shown at Fig. 11, and is ready for fixing. To enable us to do this, as its position is at the back end of the boiler, we first remove entirely No. 4 ‘raiseup’ and this must be done very carefully. A good plan is to cut out the bottom of the ‘raiseup,’ insert your finger and gently pull it, when, with a little coaxing, it will probably come out easily. The ‘raiseup’ being removed, we fix the screen firmly in its place, using plenty of gum on the inner side of the ‘over-raiseup,’ ‘side-boxes,’ and inner boiler end. To hold it in position while drying, stick two or three pins at the bottom into the ‘foundation,’ and tie a piece of cotton through the screen holes round the dome. This cotton must not be so tight as to pull off the dome or bend the screen. Let it dry.

The next process is to provide ‘tender-sides.’ The name indicates what they are, viz. sides to the tender. They are made of wood; two pieces, each four and a half inches long, one inch and a quarter wide, and one-eighth of an inch thick, are required. The upper corner at the front end should be cut out to correspond with the projection from side-boxes (see Fig. 5, a). Paint chrome-green, edged with black, then divide into panels with black lines, as at Fig. 12, which is full size, and gives the exact appearance. If found too difficult, omit all the inner lines. It is advisable to practise making these fine lines on a piece of paper before making them on your ‘sides.’

When they are quite ready they are placed in position (one on each side) at the rear of the ‘foundation,’ and firmly gummed. They must be in an exact line with the ‘side-boxes,’ and reach a little each way beyond the pair of tender-wheels (as shown in Fig. 1, P to R). To connect these, take a piece of ‘thick’ card of the shape shown (Fig. 13, a). The diagram is half size. At M O and N P, cut, as before explained, V-shaped grooves, and gum up the shape as at Fig. 13, b.

Paint the part marked A chrome-green; panel with black lines like sides of tender. Paint the parts marked B and C black. When quite dry, place in position; the part marked A is to be at the back end of the ‘tender-sides’ connecting them, the part marked B half-way along the top, in both cases extending to the outer edge of the wooden ‘tender-sides.’ The part marked C, which is narrower, comes between the ‘tender-sides,’ and should terminate just about the front end of them.

The ‘screen’ to be placed at this end now requires making. It should be just wide enough below to fit in between the ‘tender-sides;’ the upper part should be wide enough to reach the outside edges of the ‘tender-sides.’ The height should be a quarter of an inch less than the ‘screen’ already constructed (Fig. 11), with top-corners rounded, and with two holes near the top similar to those in the ‘screen.’ Near the bottom a hole, one inch wide and three-quarters of an inch high, should be cut—this is for the stoker to get coals out. The diagram (Fig. 14) gives the shape. Paint chrome-green, and edge with black.

If you desire to make a screen with a top to it, as in the engines more recently constructed, obtain a piece of thick card long enough for both screens (which now must be of equal height) and the top; arrange it something like the annexed figure, placing all the details of both screens as before described, and finally making V-shaped grooves at A and B, where the bends are to be made. Gum up into shape and afterwards gum in position as before described. Very often this kind of engine has no ‘tender,’ and is called a ‘tank’ engine.

Now obtain some coal and break it into small pieces—about the size of gum arabic when purchased. These are to be gummed on the card marked C, in Fig. 13 to fill the space level between it and the back screen, and thus give the appearance of a tender well filled with coal. The tender will now be as represented at Fig. 15.

Our attention must now be given to the wheels. We require five pairs. The diameter of these should be equal to the spaces cut out on the ‘foundation’ in Fig. 1, viz. one pair one inch and a quarter, one pair (fly-wheels) one inch and three-quarters, and three pairs one inch and a half. They are to be cut out of ‘thick’ card; the fly-wheels should have sixteen spokes, the others may have eight or twelve. In the centre of each wheel make a pin-hole. Fig. 16, full size, will show you how to mark and cut out your wheels. The shaded part is to be cut out neatly and carefully with a sharp knife. As each wheel is cut out, paint it chrome-green, and edge each spoke with black. Next obtain a piece or pieces of wood about three-eighths of an inch square at the end, and about one or two feet long. Cut off five pieces, each two inches and a quarter long—this is probably rather longer than required, but they can be cut shorter; they are for axles, and the ends should be painted black.

Having all these prepared, fix each pair of wheels to an axle by sticking a pin through a pin-hole. They are not to be permanently fixed until the axles are stuck on the foundation, as possibly some of the pins may require to be placed higher or lower in the axles in order that all the wheels may be level at the bottom and the engine stand firmly when on a smooth surface. When this is done, fasten the wheels very firmly to the axles with pins cut in half. I should add, the wheels are not intended to revolve. Next provide ‘bearing-shafts’ by taking strips of thin card, the same length as the foundation, and about half an inch wide; draw a line down the the middle of each from end to end. Now fit them to the sides in order to mark on them the positions of the engine-wheel centres, A, B, C. At these make curves, as shown. Cut through the line (1,2); it follows the centre line except at the curves; the bottom is quite straight. Paint this ‘vermilion,’ or better still, ‘crimson-lake,’ and edge with white. The bearing shafts are continued round the ends front and rear, but for these it is best to take separate pieces of card of medium thickness; they are only a quarter of an inch wide; paint and edge like the side pieces. Gum in position on the sides and ends of foundation; only the curved parts at A, B, C appear above, the straight part of the upper edge is ‘flush’ (that is, exactly even) with the foundation.

Our copper wire (No. 9 in list) is now needed. Cut two pieces just long enough to fit tightly between the second and third ‘raiseups,’ fix them in position parallel with boiler, rather more than half-way up, and near the edge of the ‘raiseups.’

Lamps are now to be made and fixed on the space in front; they are best made out of pieces of wood—the remainder of that used for axles will be useful for this if cut down; they should be about three-eighths of an inch wide and thick, and half an inch high. Paint the front side of one white, of the other green; when dry, make a circle on this front, and paint all black except within the circles; make two similar for the back, but these paint vermilion for the centres. In the top of each insert a bent pin with its head cut off for a handle.

Now make the buffers, the instructions for making steam-funnel will tell you how: the only difference is that there is to be no hole in the circular card at the end. The front part is painted vermilion, the rest black. Two are required at each end; they are placed on the bearing-shafts front and rear, about three-eighths of an inch from the sides.

The ‘FUNNEL’ now requires our attention. It is made of paper, long enough and wide enough, when tightly rolled, to form a cylinder about half an inch in diameter and two inches long. Gum the edge down. For the top, cut a circular ring, of medium card, three-quarters of an inch in diameter outside, half an inch in diameter inside. Fit this neatly on the top of the cylinder. Paint it black and gum in the centre of the funnel-box, previously described. A gold line or strip of gilt paper round the top of the funnel improves the appearance.

A circular piece of medium card three-quarters of an inch in diameter, with a black cross or diamond painted on it, should be placed in front of the funnel-box. (Fig. 17).

Safety-valves, connected with the ‘dome,’ should now be put. Obtain two rather thick sewing-needles, about two inches long; make with the points two small holes, one-eighth of an inch apart, just behind the red strip at the back of the ‘dome;’ push the eye end of one of these needles carefully through these holes, so as to allow them to stand out about an inch and a half. They should incline to each other at the top, but otherwise be perpendicular. They are connected with the dome by pins with the heads cut off, but whose points are stuck into a little cube of cork gummed on the top of the dome.

The engine is now tolerably complete, and only requires to be varnished. For this purpose, obtain some ‘crystal’ varnish, of good quality, and apply it with a large camel-hair brush. One good coat should suffice. Let it thoroughly dry before handling.

There are many little details which will probably occur to you. I have seen a metal cartridge-case used to represent a cylinder, a wire coming from the top representing the steam feed-pipe. Little pieces of chain, front and back, represent coupling-chains. In some, the apparatus for applying the vacuum brake is imitated. All you need do is to use your eyes and exercise your ingenuity. Should you fail at first, do not be discouraged; try once more. There are no obstacles but what may be conquered by patient and persevering attention.

II.—A Home-Made Humming-Top.

The humming-top is a familiar toy that does not cost much to buy. At the same time there is always a satisfaction in making a thing for oneself—particularly when it costs nothing.

As it happens that a good loud humming-top can be made for nothing, we feel sure that some of our readers will not be above trying their hands at it.

The materials are an empty baking-powder canister, or any wooden box, and two pieces of firewood. The plan of operations is to cut a slit in the side of the box answering to the hole in the toy, making it half an inch square or round, as the case may be, and making a hole in the lid and bottom of the box for the spindle to come through. To make a good job of it the bottom hole should be square and the top hole round, and the spindle should be cut to fit, pushing it in, of course, from the bottom. When the holes and spindle are cut, put a little glue round the lid to make the box tight, and insert the spindle with a little glue at each hole. For the usual fork or handle with which the top is spun, a plain slip of wood with a hole at the end will be found to answer.

Very simple preparations all these, and yet everything is ready except the string.

When the top is dry, wind round the string, passing it through the hole in the handle as shown, and spin.

CHAPTER XXXVIII.—ARTIFICIAL WOOD: HOW TO MAKE IT AND WHAT TO MAKE OF IT.
By the late Dr. Scoffern.

You will admit, I think, that if instead of fashioning wood by tools it were possible to make the wood grow into the shape desired, it would not only be curious, but under certain circumstances useful. Suppose, for instance, I wished to have a boat; it would not only be curious, but in some cases useful, if I could make the boat grow under my eyes by almost imperceptible additions, instead of fashioning it, as now, from planks. This is just what I am going to show you how to do, and very pretty work you will find it in long evenings.

You must begin by making a fluid called cupro-ammonium (you cannot buy it), which has the singular property of dissolving woody matter just as completely as water dissolves gum. You make this cupro-ammonium thus: Go to a wholesale druggist, or a drysalter, and purchase a Winchester quart bottle full of the very strongest solution of ammonia. This is known commercially as ‘eighty-eighty’ ammonia, by which name you are to inquire for it. Were you to purchase less than the measure of a Winchester quart it would cost you a much higher proportionate price, because, being very irritating to the nose and eyes, the vendor will take good care to charge you for all the sneezes and eye-blinkings he has to encounter in measuring out your required quantity.

Next you will require an empty Winchester quart stoppered bottle, or a bottle of equal capacity. Being thus provided, you will pour just one half of the contents of the full bottle into the empty bottle; the reason for doing which will presently be seen.

Get now some copper wire—it matters not what size—and having got it, cut into such lengths that being thrust into one of your half-full Winchester quart bottles it shall lie partly immersed in the ammonia, and partly exposed to air, like this:—

You will observe that the sketch represents not one length of copper wire, but many, the fact being that the object of using copper at all is that it may be dissolved by the ammonia; and it stands to reason that in proportion as the copper is more so will the necessary strength of solution be arrived at more quickly. Contact of air being necessary to effect the solution affords the reason for your dividing the original ammonia into halves.

So your bundle of copper wire being placed in the half-full bottle as described, there let it remain and steep, but you must take care to remove the stopper of your bottle from time to time—say once a day, at least—shaking the contained fluid well about, so as to promote air contact. An interesting change will be seen to take place. The ammonia solution, originally colourless as water, grows blue and bluer still, until so very blue that you cannot see through it. To this blue solution the name of cupro-ammonia has been applied. It has the remarkable property of dissolving wood, as we shall presently discover in our workings.

Before going further I must point out to you that this cupro-ammonium has a very strong smell; not a disagreeable smell, far from it; the smell of hartshorn, in point of fact. Not an unhealthy smell, but one may easily have too much of it. To be working amidst sneezing and eyes full of water is not agreeable, so I will tell you betimes how, in your small workings, you may avoid this inconvenience. The smell depends on a colourless gas ammonia, which is a light gas and very tractable. If you sit in a draught and on the windward side whilst working, and in the open air, the ammonia is blown away from you and you smell nothing. If you work in a room and before a chimney, up which there is a draught, then again you smell nothing, because all the ammonia evolved goes up the chimney. These points being remembered, no trouble will be experienced in doing such small work as I shall teach you; but before working with cupro-ammonia could be conducted on a large manufacturing scale, as it now is conducted, special means had to be devised for disposing of the ammoniacal atmosphere.

Good, so far! And now about the tools. The hand, with its four fingers and a thumb, is so excellent a tool for an infinity of purposes, that certain thoughtless people would seem to be under the impression that whatever new thing they may have to do can be done without tools altogether. This is a mistake; tools you will want, but they are of the simplest description.

Inasmuch as cupro-ammonium not only stains the skin but irritates it, do not let it touch the skin. There is no danger in the matter, only inconvenience. You do not want the ladies of your family petulantly complaining about those boys having been ‘dabbling with their filthy chemicals.’ Should your fingers get stained, a little vinegar will get out the stain, but not without a certain smarting that may as well be avoided.

The chief tool you will have to employ will be a finger of the right hand. Some operators may prefer the forefinger to others; the second will come most natural. But whichever finger you determine to employ, case it in india-rubber. This is easily done, and as follows: Having procured a sheet of raw or unvulcanised india-rubber, cut a piece off, hold out your finger, and get some friend, after warming the rubber, to stretch it over the finger so:—finger-stall squeezing the rubber where it comes round the finger above into a flattened crest. The two surfaces will stick together quite as much as is desirable. Now let the operator, with a pair of sharp scissors, and at one sweep, cut away the crest close up to the finger. You will then have an india-rubber finger-stall.

If you choose to be a little more extravagant, you may provide yourself with an india-rubber glove. Gloves of this material are common enough now, being used for a variety of purposes, more especially by photographers for protecting their hands against the corrosive and poisonous agents employed in the practice of photography. If, however, you do use gloves, see that they are thin, fitting well to the fingers. If thick they will interfere with the delicacy of touch necessary to your working. For my part, I do not recommend gloves, looking upon a finger-stall of india-rubber as superior.

The next tool that you must get is a pair of forceps, such as watchmakers use. It is a very inexpensive instrument, costing only a few pence, and in shape it is like this:—