Chapter III: Working in Metals (1)

It would be of great advantage to every traveller if before starting on an expedition he were to spend a few hours in learning from a blacksmith how to weld together two pieces of iron, and from a tinman how to solder tin or copper. In the absence of this experience, a man who is determined to help himself need not despair of success if he will bear in mind that the chief essentials in both cases are proper heat, strict cleanliness, and sufficient quickness of manipulation without hurry. If the traveller possesses a portable forge, it is most likely he will have learned how to use it before starting; if not, he may in many countries, South Africa especially, find almost in every tribe some native who could make one; or if not, he might adopt some of the expedients described under that head. His first care should be to see that his fire burns clearly and with sufficient intensity, and this he may aid by occasionally dashing in a little water, which, by the decomposition of the gases, will increase the heat under the direct blast, while the surplus, falling on the surrounding coal, will prevent the fire spreading farther than is requisite. The broken ends of the iron to be rejoined should then be placed in the fire, one of them in the centre of the heat, and the other near enough to acquire a preparatory warmth; the first, heated to a bright orange red, should be taken out and thickened by stamping the broken point upon the anvil till it is considerably shorter than before; if the heat is sufficient, the scarf, or smooth diagonal surface which is to form one part of the welded joint, may be worked upon it; if not, it must be returned to the fire while the other part is taken out and driven up in the same manner. In using the hammer, some care is needful to proportion the force of the blow to the size and comparative heat of the metal you are working, and also to turn the iron under the hammer so that each stroke shall help to consolidate the mass instead of splitting it into fibres. When the surfaces of the scarf are worked smooth, fair, and perfectly free from scales or dirt of any kind, place them side by side in the fire and bring them to an intense white heat, so that when drawn forth they may almost spontaneously give off small white sparks. We would add a caution against burning the iron, or partially fusing it, by too much heat, but we do not think a traveller with an extempore forge is in much danger of doing this. The anvil should now be perfectly clean; the "smith," with his hammer ready in his right hand, should grasp with his left one of the pieces while his attendant draws out the other and lays it with the scarfed side uppermost on the anvil; prompt action without hurry is now the one thing needful: the smith withdraws his piece, lays it with its scarf turned downwards on that of the assistant's, and with one decisive stroke of the hand-hammer unites them; a few more smart and rapid strokes while the iron is slightly turned to and fro to receive them properly, complete the union; and when the first heat is lost the iron is again put into the fire, and the joint which, owing to the thickening and shortening previously described, should present a clumsy appearance, may be trimmed and hammered down to its proper dimensions, the iron, if this is neatly done, having lost but little of its original length; and it is now for the operator to judge whether he will restore this by beating the metal a little thinner or sacrifice a little of it for the sake of retaining the original thickness. Among the Kafirs a rock is most frequently used for an anvil, and a smaller stone for a hammer. The West Africans use a conical block of iron, about the size and shape of the link extinguishers, some of which may yet be seen before old houses in London. The work has, in consequence, a slightly indented appearance, which distinguishes it from the smooth-faced hammer-work of England; but their weapons are of excellent metal, and so flexible, that they will almost tie in a knot rather than break. The Abyssinians also use weapons of this temper; for they say if a steel sword breaks, who can mend it, but if it bends we can sit on it and straighten it.

{Scrap and hoop iron.}

We have often made very good knives for skinning or cutting up animals from the handles of broken gridirons, frying-pans, stout hoop, or other bits of iron. Broken sheep-shears are also excellent substitutes. The hoop iron used to bind the bundles of compressed hay issued to troop horses can be made use of for an immense number of useful purposes. The walls of many of the stables we erected in the Crimea were composed entirely of this material, closely interwoven, like basketwork. Excellent gabions can be made from it, as can the framework of hut roofs. A piece a couple of yards long, doubled forward and back in zigzag form, makes an excellent gridiron. Short pieces, straightened out by hammering, form useful make-shift knife blades for the use of native servants. Tent poles are greatly strengthened by having a spiral strapping of this iron nailed to them. Saws for cutting or rather fretting blocks of stone can be made by stretching a strip of this material edgewise in a wooden frame, aided by water, sharp sand, and a suitable balance weight, such as marble masons use. Excellent eel traps are made by arranging long strips of hoop for a body, and then securing them by small nails, as rivets, to hoops made from the same material. Eel traps will be fully described under the head of "Fishing." We once made a complete set of bars for the bottom and front of a camp stove entirely of forage hoop iron, made a scraper for the door, a set of hooks for a gun rack, and a set of cross hooks to hang meat on. Never heedlessly throw away forage iron.

Trimming and filing up are matters which may be left very much to the taste and opportunities of the traveller, but it should be remembered that, _cæteris paribus_, a neatly finished piece of work, besides being more satisfactory to the eye, is in itself stronger, as the inequalities, flakes, flaws, or roughnesses of the surface, which, under any strain, might form the commencement of a fracture, are removed; and besides this, especially in wet climates, a well smoothed piece of work is less liable to rust in patches than one of unequal surface. If you intend to file-finish your work, remember to let it cool slowly, and do not harden it by immersion in water.

{The use of cold or of joiners' chisels.}

In some cases incisions may be required, too sharp or clean to be cut with a file, and, if proper care be taken, a fine, sharp, joiner's chisel may be used without more injury than may be set right by fresh grinding it; it is advisable, however, first to render the angle at which the edge is set a little more obtuse, so as to lessen the danger of flawing it, taking care at the same time to keep it as keen as possible.

{Tires and wheels.}

In all expeditions in which wheeled vehicles are used, nothing causes more trouble than the loosening of the tires, owing to the shrinking of the woodwork, and possibly some slight expansion of the metal, from the heavy pressure on the rough roads, as well as from the intense heat of a tropical climate. If sufficient skill be available, the proper course is to cut and shorten the tire, for all other make-shifts have the disadvantage either of being insecure, or positively injurious to the fabric of the wheel. Supposing the shortening to be determined on, the tire must be taken off, and if, as is frequently the case, it be fastened with rivets through the felloes, the clinch on the inner ends of the bolts must be first cut or filed away, the "washers" or iron rings taken off, and the rivets themselves driven back with a long punch or drift pin; the "band" or tire will then either fall off or require but a few blows to detach it. The streaks used to protect the wheels of field artillery guns and waggons are removed and replaced separately.

It is impossible to measure the relative circumference of the felloes and the _inner side_ of the band without an instrument similar to the perambulator; _i. e._ a wheel or disc of wood or metal, mounted on a handle. A chalk mark is made on the felloe and a corresponding one on the edge of the disc; the two are set together, and the disc--say 1ft. 6in. in circumference--will then revolve perhaps ten and a half times in going round the hinder wheel of a Cape waggon of about 5ft. diameter. As soon as the disc has again reached the starting point another chalk mark is to be made upon it, and the distance between the two marks on the disc, say 9in., is to be added to the number of revolutions counted; it is then to be applied to the inner side of the band, the ten revolutions counted off, the additional 9in. to be run, and the distance between the starting point and the finish of its course is the amount by which the band is too long. Some judgment is required to decide whether more or less than this piece shall be taken out. If the wheel looks very firm and close in its joints, perhaps a little less should be cut, as the overlapping of the weld will take up a trifle--especially if it be not very skilfully and neatly done; if the wheel is loose and the spokes not firmly shouldered up to the nave, a little more may be taken away; and in this case it is proper to estimate whether the felloes will close up sufficiently to force the spokes home upon the nave; if not, the ends of four or more felloes opposite each other should be cut a trifle shorter with a fine tenon saw, great care being taken not to cut the dowels by which the ends of the felloes are kept true to each other. A smooth, hard place must now be sought out, on which the wheel can be laid flat, the front downwards, a hole being dug, if necessary, for the reception of the nave; flat stones, plates of iron, or slabs of hard wood, laid evenly under the circumference, would be of advantage when the shortened band is to be driven on. The next essentials are plenty of water and abundance of heating power. The ends of the band must now be heated, and the smith will bevel off each of them, one from the inside and the other from the out, so as to form the scarf; an attendant or two holding the band, as he directs, upon the anvil. The tire should now be reversed, and the curvature increased by resting it on two points of support and striking heavily between them on its inner surface till the scarfed ends close upon and begin to overlap each other. It is again placed in the fire with the ends equally exposed to the intense heat, and at the proper moment is lifted out by two attendants and promptly, but carefully, placed upon the anvil; a few smart decisive blows are given, and the joint is made. The hammer man now comes to the assistance of the smith and consolidates it by striking alternate blows with the "sledge," under his direction. The circumference is again tried with the revolving disc, and if it be too short, as it ought rather to be, it is again heated and hammered out, the weld, if this be rightly done, gaining solidity in the process. The band is then laid upon the ground and a fire of wood, dry cow dung, or other material made, so as to heat it to redness through its whole circumference. It is then lifted by tongs or other means (if hooks are used they must be applied from the outside), and placed upon the wheel, and, as quickly as possible, hammered down nearly into its true position. The workmen will soon find what "smoke to the eyes" is like, but they must disregard this, and, before the wood is too much burned away, quantities of cold water must be dashed on, the hammer men all the while beating down the shrinking band to a level with the felloes; before it is quite cold the wheel should be caught up and brought to the anvil, or a smooth rock, where the tire is faced up true to the felloe front by heavy blows, and finally cooled off and tightened by another deluge of cold water.

Everything depends upon prompt action; and the tiring of a set of waggon wheels at some out station is really an exciting event, at which all hands are required to work with a will.

{Repair of perch-bolts.}

Not unfrequently the "schammel-bolt" or perch-bolt will give way in the grip, and if this flaw be detected in time, and the bolt be long enough, the evil day may be staved off by removing it, boring a hole through the "buik" plank or floor of the waggon, right above, and dropping the bolt down through it so that its head remains 3in. or 4in. higher than before, and the nip is brought upon a fresh place, as shown by the dotted line above H (p. 216).

{Extempore anvils and vices.}

For small work, the "reim schoen," or drag, turned up upon a block of wood, will form a very decent anvil; and the next essential is a vice, which ought to be as large and powerful as can be carried. A weak inefficient vice is worse than useless. The means of attaching it ought also to be good, for if it is not firmly fixed no work can be properly finished in it. No part of the waggon ought to be used as a holdfast for the vice, unless indeed it were properly fitted with iron guards for that purpose before starting, for the claws and screw-bolts would speedily tear and split the wood, and only damage the vehicle to no purpose. It would generally be better to cut down a convenient tree, leaving a stump about 3-1/2ft. high, and in this to cut a niche, partly to let the vice in: it might then be secured by hoops of iron, if available, such as the nave bands, or anything similar, tightened with wedges, and lashed in its place by thongs of raw hide, which, when they dry, acquire almost the rigidity of iron.

If the vice cannot be fixed firmly, it is better to cut with the saw a deep groove down into the solid stump, and, having inserted the iron you wish to file, to tighten it with wedges, screws, lashings, or such other appliances as you may have at hand (p. 166).

The tapping of screws on bolts or nuts, especially if of any size, requires that the work be firmly held; but we should rather advise that duplicate bolts and nuts of the principal sizes used in waggon work--1/2in., 3/4in., 7/8in., and 1in.--be carried, as a set of taps and dies could not be had even in Cape Town for much less than £5, and an unskilled hand would be more likely to break the instruments than use them to advantage. For the smaller sizes, suitable for gun-locks, &c., a plate and set of taps might advantageously be carried.

{Cutting bolts and gun-barrels.}

Sometimes a bolt, rod of iron, or a gun-barrel, has to be cut off to a given length, and the most convenient way of doing this is to file a row of small teeth upon the back of a handsaw, and with it to saw off the superfluous iron: the first illustration shows the manner of cutting the teeth, and their exact size and shape. Always put in a bit of copper, lead, or leather to protect the gun-barrels from the grip of the vice. It may, perhaps, be well to remark here, that nearly all Russian saws are made to cut backwards, and all the gun breech-screws made in that country are cut the reverse way to ours.

For repairs of guns, it is well to have sufficient wire of different thicknesses; but when a hardened pivot is required, a broken gimlet or a bradawl will often supply the material; and we have before now earned a goat or sheep for dinner by supplying in this manner some deficiency in the arms brought to the white man to be repaired. It is convenient to buy a musket-lock or two before starting, and to save all sorts of screws, tumblers, springs, &c., out of old locks.

We were once asked, far away in Namaqualand, to perform no less a service for a friend than to put a new hammer on his gun. Modest disclaimers of ability were not received, and there was nothing left but to do our best. We found a bit of flat iron, which, fortunately, had a hole in it: this we first squared up with a small "three-square" file, and then fitting it to the tumbler, and making sure that the flat surface of the hammer should strike upon the nipple, laboriously cut and filed away the intermediate parts, and before morning the hammer was fixed. Mr. Rae, the engineer of the Zambesi expedition, proceeded more scientifically; he employed a native to weld up a quantity of iron hooping into a plate quite thick and large enough to make the hammer, then, drawing the outline, he bored small holes close together all round it, broke off the superfluous iron, and finished with the file.

On one occasion we were unfortunate enough to break the little S-shaped bridle which connects the claw of the mainspring with the arm of the tumbler. Most of our readers will remember that this portion of a gun-lock is of a most peculiar form, being not only S-shaped, but flat-cheeked and T-ended. Notwithstanding the apparently complicated nature of the undertaking, a new one had to be made; so we proceeded as follows:--One of our small mining picks chanced to have an iron wedge (which had originally been cut from an old patten iron) in the handle. This we softened in the fire, worked into form on the head of an upturned hammer with one of smaller size, and then roughly finished it up with a handsaw file. The screw hole had then to be made, and, as we had no drill, we took the scissors from our fishing-book, ground down the point on our bit of Turkey hone, tempered it in the candle, and then, by dint of hard labour and persistent boring, made a hole through the end of the bridle. We then gave our work a few finishing touches, tied it up in a bit of old leather, heated it in the fire, plunged it in water to case-harden, and then secured it in the lock, where it performed its work well until we parted with the gun so repaired.

{Sighting guns.}

Most of the hunters in South Africa find that ivory, from its agreeable creamy white, is better adapted for the "korel," or front sight of a gun, than the polished metal used for that purpose by the maker. Sometimes the sight is accidentally lost, and has to be replaced; but more frequently the dazzling bit of metal is purposely knocked off.

A broad flat groove, say 1/2in. broad, or as wide as a handsaw file, and 1/16in. deep, is cut across the midrib of the gun (Fig. 1), and the edges of this are under cut, either with a sharp-edged file, or, if the operator is expert in the use of tools, with a chisel and mallet. A piece of ivory (Fig. 3), cut so that the grain runs with the length of the barrel, and with an elevated ridge left in the centre, is then fitted tightly in, adjusted as nearly as possible, and the metal clinched down upon it; then the central ridge is filed on either side until, by occasionally firing at a mark, the gun is found to shoot without lateral deviation. It should, in the beginning, be considerably too high, and should then be filed down so as to carry the bullet point blank to its mark at a hundred yards.

If the back sight is lost, cut a notch across the midrib as before, and fashion a piece of iron (Fig. 2) to the same shape as you did your ivory, only let the elevated ridge in this case be across the barrel. File a notch in the centre, and leave the iron a little wider than the rib, so that it may admit of being driven a little to either side, and the superfluous metal filed off when the adjustment is nearly perfected. Mark it, and take it out to do this; then put it in again, clinch it, and test it by firing at a mark.

Figs. 4 and 5 represent the position of the two sights. If the gun shoots to the right, shift the back sight (Fig. 6) to the left and the front sight (Fig. 7) to the right; if to the left, shift the back sight (Fig. 8) to the right, and the front one (Fig. 9) to the left. If the gun shoots too low, file down the front sight; if too high, file down the notch of the back sight.

In one of our own rifles the front sight was, as usual in military patterns, based on the block of iron which forms the check for the bayonet (Fig. 11). We did not remove this, but cut behind it a very shallow groove an inch broad, and in this fixed and soldered a piece of iron with a longitudinal groove, to carry a knife-edged sight of ivory, as seen in Fig. 10.

For night shooting, we used the only sixpence to be found amongst our party; bending and polishing it and clinching it on to a saddle of zinc painted black. Holes were punched in this for leather thongs, and in front was a notch cut to fit the actual sight, and so insure the central position of the silver one when in use (Fig. 13). By day the saddle was turned beneath the barrel (Fig. 12), and the little flat thongs of antelope hide were not at all in the way. With guns not of military pattern the sight could not so conveniently be turned under, but would have to be removed by day; but we should think a broad silver sight might be fixed on a steel spring on the rib behind the sight, with a broad ring to slip over and keep it down by day, as in Fig. 15, or to draw back and let it rise into view by night as in Fig. 14 (p. 201). For the same purpose our late friend, C. J. Andersson, used to wrap a bit of white paper round the muzzle of his gun, pinching it up in the centre, or laying a cord under it to give it a little elevation (Fig. 16).

As a protection, and also for the contrast of the colours, the Dutch, and many of the English colonists, stitch very tightly over all a bit of skin from the inside of the elephant's ear (Fig. 17). This is very fine, exceedingly strong, and, when rubbed with a little grease, intensely black; it is then very carefully cut, to allow the front sight to appear through, and left to dry. Another advantage of this plan is, that it corrects the errors often caused by the mirage or refraction of the sun's rays from the polished barrel, which, especially in the tropics, causes the object aimed at to become indistinct, to assume the appearance of motion, and to be seen sometimes considerably above its true position, thereby causing the marksman to miss by shooting over it.

{Sheath knives or bayonets.}

No wise traveller ever encumbers himself with a long sword or bayonet of ordinary pattern; but every one carries a sheath knife, of from 6in. to 12in. in the blade; and the handle of this ought to be made so that it may fix as a bayonet on his gun. We have seen natives considerably astonished by this sudden conversion of our gun into a spear to kill a wounded animal.

If the knife handle were simply made round, so as to stick into the barrel, like the bayonet of old times, it would be better than nothing; but if the side-springs were generally adopted, it might be well to arm our troops, intended for service in wild countries, with a good serviceable sheath knife, of 8in. or 10in. in the blade, to be used for general purposes, and fixed as a bayonet when wanted, rather than with the orthodox triangular needle, that is only of use in opportunities that occur but rarely. We remember a party of a certain line regiment coming upon a number of Hottentots, when their officer ordered them to fix bayonets, forgetting for the moment that as usual they had been left at home--just as were the swords and steel scabbards of the Cape Corps--lest their rattling should give warning to the crafty foe. It is a common custom in India, when real work has to be done, to throw aside the steel scabbards and replace them with wooden ones, which have the double advantage of being noiseless and a preservative to the edge of the sword. We have heard a man of the Rifle Brigade say, he should not fear even though lost in the bush. "Shoot the first Kafir that attacks you," said he, "and arm yourself with his assegai, and no other will come near you."

Our allies, the Fingoes, in the war of 1850-53, generally carried one or more assegais, using the shaft as a ramrod, or holding two of them crosswise in the left hand as a rest for the musket. The Kafirs, when hard pressed, retain the largest assegai, and, breaking off the shaft, use it as a sword or dagger. The contest is often prolonged by picking up the assegais thrown by the other party, and sending them back again. To prevent this, sometimes a tribe, bent on a sharp decisive conflict, will cut the shaft half through, so that it may break when it strikes, and become useless to the enemy.

The Dutch Boer sits down, rests his elbows on his knees, and extending his left arm, with the ramrod grasped firmly and planted on the ground, obtains an almost immovable rest for his heavy roer. Many of them shoot from the left shoulder, and some few can shoot from either shoulder equally well--an immense advantage if a man on horseback is surrounded by enemies.

{Watch-key, to make.}

In an out-of-the way corner of Central India we were so unfortunate as to lose our watch-key--the last of three. This we replaced as follows: We first routed out a piece of soft steel about the size of a small black-lead pencil. After filing off one end perfectly flush, we placed it in the fire, whilst we prepared the square end of a saddler's awl by grinding it to the exact size of the key-square of the fusee of the watch. When the steel was heated to a cherry red, we fixed it upright in the vice, and then supporting the bit of awl with a pair of pliers we, with a light hammer, drove it a fair distance into the steel bar. When it cooled, it was reheated, and the bit of awl driven deeper, until a square hole of sufficient depth was formed. The bar was then filed down to the size of the key-hole of the watch. The requisite length was then cut off; the end flattened out for a thumb-piece; and a hole drilled in it to pass a thin strip of tendon through. A few finishing touches were given with a fine file; the work was heated to a blue heat on a bit of red-hot iron, and was then dropped into a cup of water. So we made our watch-key, which did its work well through about 4000 miles of travelling, and was as good as new when we returned to England with it hanging at our whip-cord watch-guard.

{Tools, to temper.}

In all cases in which heat is required for iron work care should be taken that the fire is perfectly clear, especially if it has been previously used for melting lead, when any dross or other extraneous matter should be scrupulously cleared out. Sulphur in any form is most destructive. It would be well that the operator should learn before starting how to work up and fresh temper a cold chisel, or punch, or even to make one if needful out of a broken file or rasp; of course, the punch is round, square, or octagonal, according to circumstances, and generally flat at the end to drive back the nail or bolt that is to be withdrawn. Sometimes a tapered point on a triangular instrument, such as a handsaw file, with the edges sharpened, is useful for driving into a broken nipple, and by turning it against the sun to extract it when sufficient hold has not been left for the usual nipple key. The cold chisel is first forged to a chisel edge, more or less finely tapering according to the strength required, the two sides forming an angle of about 15° to 20° with each other; the cantle is then filed or ground till its sides form an angle of from 45° to 90°; it is then heated to a cherry red, and dipped in water cautiously at first, being frequently taken out and watched during the process till it assumes a pale straw colour, a deeper tint or even a deep blue or purple, according to the degree of hardness required, and is finally ground sharp upon a stone with plenty of cold water. Small tools may be tempered by laying them on a piece of red-hot iron, such as a bit of waggon-wheel tire; the changing colours should be watched, and when the desired tint appears the tool may be plunged into water. Should it be too hard the temper may be reduced by dry grinding; when a temper not quite so hard and less liable to fly is required, it may be given by cooling the steel in grease or oil. The tools carried for this purpose must vary according to the means of conveyance. On the North Australian Expedition we had a portable forge, which remained at the main camp, but on our inland journeys with packed horses we took as many horse-shoes as were thought requisite, a small hand hammer, a pair of tongs, a few files, rasps and punches, and a supply of nails.

{Case-hardening.}

It not unfrequently happens that some object, such as a fish-hook, key, portion of a gun-lock, or gun furniture, will require being so treated as to harden the surface whilst toughness of texture is retained. This process is known as case-hardening, which is, as its name implies, one by which a hard case or crust is formed over the surfaces of the articles operated on. There are numerous instruments and contrivances in constant use in the construction of which the toughness of iron combined with the hardness of steel, communicated by the process about to be described, is taken advantage of. Gun furniture, fish-hooks, and handcuffs are examples, the latter most remarkedly so, as, were they composed of ordinary iron, nothing would be more easy than to file or saw them through; if of steel, a blow with a stone, or any other heavy substance, would break them as though made of earthenware. When case-hardened neither of these devices is available. Too hard to cut, too tough to break, the metal is all that can be desired. Having fashioned, filed up, and finished the article or articles in hand, procure a fair quantity of leather cuttings, or horsehoof parings. These should be roasted crisp, and pounded up until a sufficient quantity of coarse powder is obtained to bury the "work" when laid in a little iron box, which can be conveniently made by doubling up the edges and ends of a bit of sheet iron. In the absence of iron, clay may be used to form the box. This, when filled and gently pressed down, must be placed, when dry, in a clear bright fire, and heated up to a blood red heat, at which temperature it should be allowed to remain for a short time, taking care not to increase it. The box and its contents may then be withdrawn with the tongs, and thrown into a pail of cold water. The work may, when cold, be washed and brushed clean, made thoroughly dry, oiled, and put aside for use. Ferrocyanide of potassium is also extensively used for case-hardening, being either sprinkled over the work when hot, or mixed with some convenient substance, such as dried cow dung, and placed in the box; but, unless in the hands of those accustomed to use it, the surfaces of the work at times become "pitted" from the contact of stray particles of the salt.

{To platinise iron, &c.}

Professor Church gives the following directions for covering the surfaces of metallic objects with a film of platinum: "Dissolve in 1oz. of distilled water 60grs. of bichloride of platinum and 60grs. of pure honey. Add to the above solution 3/4oz. of spirits of wine, and 1/4oz. of ether. The mixed liquids, if not quite clear, must be filtered through a piece of white blotting-paper. The objects to be platinised, which may be of iron, steel, copper, bronze, or brass, are to be thoroughly cleaned by washing them in soda, then in water. When they have been dried they require heating over a lamp to a heat below redness. For this purpose they may be suspended, by means of a fine wire, over a spirit or an oil lamp, in such a way as not to touch the flame. Suddenly, before they have had time to cool, the objects are to be completely plunged beneath the surface of the platinising liquid. One immersion for a single minute generally suffices, but the process may be repeated if necessary, care being taken to wash and dry the pieces operated upon before re-heating them. The composition of the solution may vary considerably, and yet good results be obtained. Sometimes the addition of more honey improves it; sometimes the proportion of bichloride of platinum may be increased or diminished with advantage. Indeed, it will be found that the appearance of the platinum film deposited upon the objects may be altered by changing the proportion of the bichloride present. The solution may be used several times; gradually, however, it loses all its platinum, the place of this element being taken by the iron or copper dissolved off the immersed objects."

If the film of platinum deposited by this method is found to be permanently adherent, the plan promises to be very valuable. It would be a great boon to travellers in warm, damp countries to be able to protect iron and steel articles by so simple a process. In the same article Professor Church describes a new and very simple plan of inlaying iron with silver, and also for enamelling metals with different colours. Both these processes really come within the scope of amateurs, and we can strongly recommend the entire paper to those interested in the chemical arts.

We may now appropriately mention a few examples where this platinising process seems to furnish desirable results. Articles made of iron or steel--watch-chains, seals, sword-handles, keys, and similar useful or ornamental objects--are greatly improved in appearance, and, moreover, preserved from all chance of rusting, by this treatment. The colour of the platinum film is of a neutral greyish black, and it often shows at the same time a faint iridescence. Iron or steel which has been inlaid with gold or silver, forming what is known as damascene work, is greatly improved by platinising. Neither the gold nor the silver are in the least degree affected, and they will be found to afford a better contrast with the colour of the platinised than with that of the original iron.

{To preserve iron from rusting.}

Iron which has become deeply rusted cannot be platinised by our process. In order, however, to preserve from further destruction objects of steel or iron having an archæological or artistic interest, a very excellent plan may be used as a substitute. The purest white paraffine is to be melted in a clean pan, and maintained at about the temperature of boiling water. The rusted and corroded specimens are to be immersed in this paraffine bath till they cease to froth from escape of moisture. They are then withdrawn, wrapped in blotting-paper, and kept in a warm place till the excess of paraffine has been absorbed. The objects thus treated, while preserved from further decay, do not acquire that disagreeable greasy aspect which the varnish ordinarily used imparts. We have been obliged to tar our saw blades, which was very inconvenient in working, but this was better than having them spoiled by rust.

{Smith's tools.}

If the traveller has a waggon, as in South Africa, he may either carry a portable forge or trust to finding natives capable of building one and supplying bellows of their own manufacture. If he thinks the weight of a small anvil too great, he should carry a heavy sledge hammer, which will serve as an anvil for ordinary purposes; two hand hammers of different weights; half-a-dozen pair of tongs, of such form and size as will enable him conveniently to hold the different sizes of work he may find necessary to do; at least a dozen files or more--square, flat, half-round, or rat-tail; and of these the temper should never be destroyed by working with them on iron that has not yet become cool, though occasionally time may be saved by using a worn-out file to work on iron while it is yet hot and comparatively soft; cold chisels of different sizes, from small ones of 1/4in. or 1/2in. wide, to be tapped with a small hand hammer, to others of 1-1/2in., to be held by pieces of rod iron coiled round them, or still better by rods of osier, and to be struck with the sledge hammer; if there is an anvil, of course a chisel to fix upright in the hole provided will be taken with it; punches of various sizes, and a stock and set of drills for boring holes up to 1/2in. in diameter, with rymers, or tapering four-edged tools for gradually enlarging them, and countersinks for letting in the heads of screws, &c., to the surface level. For small work, such as gun-locks, &c., an Archimedean drill and set of bits are very convenient, a hand-vice and set of gunsmith's small files--triangular, square, flat, half-round, round, and knife-edged--should accompany them.

{Muskets, to repair.}

A traveller will frequently have occasion either for his own servants or for the natives of the country to put "fresh fire" into the pan cover of a musket; for this purpose nothing is better than the blade of an old saw, the thinner the better; a piece is broken off, softened and filed down to the exact size; it is then bent so as to fit the face of the pan-cover, and is bound on to it by several turns of iron wire, not drawn so tightly but that bits of copper wire may be thrust beneath them all round the edges that are to be joined; borax, dissolved in water, is now laid on with an old brush, and, if necessary, small lumps are also added, and the whole is placed in the fire and heated till the copper melts and brazes the two parts firmly together; let it cool slowly, finish it carefully with the file, heat it to a dull red, and temper by cooling it in water. Half-civilised Hottentots frequently do this.

{Fish-hooks, to make.}

The snoek-hook used in Table Bay is a bit of brass wire as thick as a quill and 7in. long; the point is filed sharp, and the barb is merely such a triangular notch as might be made with a handsaw file. It is not bent in a true sweeping curve, like our fish-hooks, but turned sharply up at about 2in. from the point, so that when the lip is pierced, it slips at once into the sharp bend of the hook, and the struggles of the fish are less likely to break it than they would be if it afforded the leverage that the usual form of fish-hook gives. (See Fig. 20, p. 211.)

Fish-hooks can be made by taking a wire or rod of the required size and softening it by heating it to a bright red and letting it cool very slowly in sawdust or leaving it till the fire dies out; let the soft end abut against something solid, and, with a sharp chisel and mallet, make a deep cut at such an angle as to form the barb; file up the point, heat it again, and bend it round a stick of the proper size so that the curve may be true. We have, before now, broken up a gridiron at the galley fire, and with a hook thus formed from one of the bars caught a young shark, whose flesh formed a very desirable addition to our fare. On another occasion, while exploring a branch of the Victoria River, in North Australia, we halted, as usual, at noon, with scanty rations, which Mr. Gregory improved by taking from his hat a stout sewing needle, softening it in the fire, and bending it into a fish-hook, baited with grasshoppers; a few strands of thread made a sufficiently strong line, a small sapling formed a rod, and, in a few minutes, he had caught three fish, resembling mullet, nearly 18in. long. The needle had done good service, but was too precious to be thrown away, so Mr. Gregory carefully restored it to its pristine straightness, tempered it, and again stuck it in his hat, to be used, when required, for its legitimate purpose.

{Brass, and its treatment.}

It is rather curious that with brass the softening process is the very reverse of that we use with iron. Heat a bit of brass and plunge it into cold water, and, with a sharp knife or chisel, you may carve it almost like pewter; heat it again when finished, let it cool slowly, and it becomes as hard as before.

A traveller in Africa should be well provided with brass, the best form being that of stout wire as thick as stair carpet rods; this will serve for many useful purposes: hooks, rings, ramrods for guns, or almost anything can be made of it. While, in lengths sufficient to make armlets, it is always a convenient medium of barter, or payment for the services of the natives, who, though they will give nothing for hollow lacquered curtain rings, will always appreciate solid metal, that may be cut, worn away, or broken, and remains the same throughout.

{Tinning Copper.}

To tin copper: first clean the surface carefully by rubbing it with sandpaper or stone, or washing it with diluted nitric acid or aquafortis; heat it till it is rather too warm to handle, by placing a hot iron or pan of fire under the part to be tinned; rub on, with a feather, a little hydrochloric acid (commonly called spirits of salt) with zinc dissolved in it; then, with a soldering bolt previously rubbed on sal-ammoniac, touch the bit of tin you hold upon the copper, and, as you melt it, spread it evenly with a bit of rag over the surface you wish to tin; this ought to be done with the insides of all copper vessels that are to be used for containing liquids or for cooking, and also for the edges of sheets that are afterwards to be soldered together. Even if the edges were to be riveted, it would still be advisable to tin them, as they might then also be soldered by slightly heating them and running a little tin into the joint, by means of the heated bolt rubbed on sal-ammoniac, as before.

Small iron nails, tacks, fish-hooks, &c., are protected from the effects of rust by tinning. The process is carried out as follows:--First cleanse the objects to be operated on in diluted sulphuric acid, then place them with broken fragments of tin and sal-ammoniac in an earthenware bottle over a strong charcoal fire. When the coating of tin is found to be complete, they are first washed in clean water, and then dried in hot bran or sawdust.

{Sheet metal, to join.}

A very strong joint may be made by turning up, say 1/2in., more or less, of the edge of one sheet (Fig. 1), then laying in it the edge of the other (Fig. 2), and turning up the edges of both (Fig. 3); then, keeping the joint pressed down, lift up the second sheet as you would open a book, and press it out flat and open (Fig. 4). You cannot make this joint in the two edges of the same sheet, turned round upon each other (Fig. 5), unless you first nearly flatten the two parts (Fig. 6), when they may be doubled upon each other, and the sheet restored to its cylindrical form by the insertion of any pointed cylinder, such as, for instance, the horn of the anvil or a block of wood rounded and tapered at the end (Fig. 7). Suppose it is required to make a pannikin, this joint, whether previously tinned so that it may be soldered or not, is the only proper one, but the corners should previously have been cut away, so that only a single or, at most, a slightly overlapping double thickness may be left at top and bottom (Fig. 8). The bottom edge is now turned outwards by gently tapping it on the block or anvil edge with a hammer till it resembles a narrow flange (Fig. 9). A circular piece is now cut for the bottom so much larger as to allow a rim to be turned up all round (Fig. 10), and to admit the flange within it (Fig. 11); then setting it flat upon the anvil, and forcing into it a block of wood that has been cut perfectly to fit it, clinch down the rim of the bottom upon the flange (Fig. 12), and turn them both up against the side together (Fig. 13). The top edge may now be rolled over in the same manner, and it will give additional strength if the rim is strengthened by the insertion of a piece of wire. If the foregoing joints have been carefully made you will have a water-tight and, what is more, a fireproof pannikin with or without the aid of solder, and a handle can be riveted on or not just as suits your convenience. One great advantage of the folded joint is, that if it is not too tightly hammered down, the parts will slide freely on each other, and advantage may be taken of this for making an opening in one side of a cannister to be closed by a sliding lid; or, if you are making a pannikin or other vessel, and your metal is not large enough to make the whole circumference in one piece, cut a small strip (Fig. 14) of the breadth you wish the joint, say 3/16in. or 1/4in., and fold the edge of the metal twice over it (Fig. 15), then draw it out; do the same with the other edge, and also with the edges of the piece you intend to insert (Fig. 16), and you may then, with a little care, slip the parts together, and clinch down the joints as closely as you wish (Fig. 17). If the corners have previously been snipped off, or smoothed with a file, it will considerably increase the facility of doing this.

{Utilisation of meat tin cases.}

During the North Australian Expedition, when Mr. Gregory was preparing for the journey from the Victoria River to the Albert, in the Gulf of Carpentaria, he collected all the emptied preserved meat tins, and burning off the old paint by placing them above the forge fire, smoothed down the tin upon the surface with a piece of _greasy_ rag, trimmed up the ragged edges, and, in most cases, obtained sheets of tinned iron nearly equal to new; from these he made pannikins of graduated sizes, in fact a nest of them, one fitting into the other from the largest to the least, thus securing comfort and convenience to his party, and utilising material which many persons would have thrown away as useless.

In opening a packing case lined with tin, care should be taken to cut the edges as clean as possible, for not only are ragged points liable to tear the hands very disagreeably, but if you wish to make use of the tin in any other manner, it is of great importance that it should be kept quite clean, flat, and free from unsightly wrinkles; a smooth sheet of tin may be cut, turned, or bent almost at will, but if it has previously been wrinkled, it is absolutely impossible to restore it to flatness, and to make a true joint in it is as much out of the question as to write freely on note paper fall of unsightly folds or creases. For cutting tin or other sheet metal, a pair of small tin snips, say 8in. or 9in. in total length, will be found exceedingly useful: stout copper or sheet-iron may be cut with them.

{Dishes and plates, to make.}

To make plates or dishes of sheet iron or other metal, cut out a disc or oval, of the size you wish, and then draw a line parallel to the edge all round it (Fig. 18); then draw lines radiating from the centre, like points on a compass card, as many as you please, say twelve, which will divide each quarter into three parts, answering to the hours on a clock face.

Make a small hollow across the end of a block of wood, the stem of the nearest small tree cut off at a convenient length for instance, lay the edge of your plate on it with one of the radiating lines corresponding with the hollow; strike it with the edge of your hammer till you have slightly indented it, do the same on the opposite side, and then with the other two quarters; repeat this all round, and you will have a very neat and useful plate, with scolloped edges like the patty pans usually sold by tinmen (Fig. 19).

{Rivets.}

A few rivets of various sizes, of iron, tin, and copper, should be taken; but, if the work is to be exposed to the action of the water, care should be taken not to fasten iron sheets with copper rivets, as the action of the metals on each other will be most destructive.

Tin rivets may be used to fasten any other metal where great strength is not required, and they are very advantageous for many purposes, as handles of tin or copper pannikins. By these we mean rivets of tin, not of iron tinned over, which also are useful, but not so easily worked.

{Make-shift forge and bellows.}

To extemporise a forge and bellows, the natives of Africa and India, who invariably squat down to their work, simply make their fire on the ground, which is previously smoothed and clayed over; behind this is raised a bank or fence of clay, perforated for the admission of a tube, either of wood of the bark of a small tree, or of the horn of an ox, or other large animal.

Their bellows are variously formed, but in every instance a pair are used, being worked alternately, one with the right hand and the other with the left, so as to keep up a continuous blast. They are generally formed of goat or antelope skins of about the same size, which are skinned off as "sacks," and braiied or softened in the usual manner.