7. The process of making combs from the horns of cattle, is not difficult to be understood. The tips and buts are first cut off with a saw, and the remaining portion is also divided longitudinally on one side with the same instrument. The horns are then soaked for several days, and afterwards boiled in oil, to render them pliable. They are next spread out and pressed between hot iron plates. This operation clarifies the horn, and produces a plate of proper thickness.
8. After the plates thus produced, have been cut in pieces corresponding in size to the proposed combs, and when these have been shaved to a suitable thickness with instruments adapted to the purpose, the teeth are cut either with a twinning saw, as represented in the preceding cut, or with a twinning machine.
9. In the former case, the plate is fastened with a wooden clamp, by the part which is designed to be left for the back of the comb; and when twins, or two combs, are to be formed from one piece, the other end is bent down, so as to render the upper surface considerably convex. To this surface the twinning saw is applied by the hand of the workman, who makes a number of incisions; which are completed both ways with two different kinds of saws, and the end of each tooth is cut from the back of the opposite comb with an instrument called a plugging awl.
10. The twinning machine was invented, about twenty years ago, by a Mr. Thomas, of Philadelphia; but it has been successfully improved by several individuals since that time. It is, altogether, an ingenious and useful contrivance. The cutting part consists of two chisels, which are made to act on the plate alternately, and in a perpendicular direction, each chisel cutting one side of two teeth, and severing one from the opposite back, at every stroke. It is impossible, however, to form a clear conception of the manner in which the machine operates, except by actual inspection. It performs the work with great rapidity; since from one to two hundred dozens of combs can be cut in twelve hours; whereas, not one-fourth of that number can be twinned in the old method, during the same time.
11. After the teeth have been rounded, and in other respects brought to the proper form with suitable instruments, the combs are polished by rubbing them first with the dust of a peculiar kind of brick, then by applying them to a moving cylinder covered with buff leather, charged with rotten-stone, ashes, or brick-dust; and, finally, by rubbing them with the hand, charged with rotten-stone and vinegar.
12. The combs are next colored, or stained; and, as the tortoise-shell is by far the best and most expensive material for this kind of comb, the great object of the manufacturer is to produce colors as nearly resembling those of the real shell as practicable. This is done in considerable perfection, in the following manner:
13. The combs are first dipped in aqua-fortis, and then covered with a paste made of lime, pearlash, and red lead. To produce the requisite variety of shades, both taste and judgment are necessary in applying the composition, and in determining the time which it should remain upon the combs. To give the combs a still stronger resemblance to shell, they are also immersed for fifteen or twenty minutes in a dye of Nicaragua.
14. The combs having been covered with oil, they are next heated upon iron plates, and brought to the desired shape by bending them upon wooden blocks with a woollen list. The whole process is finished by rubbing off the oil with a silk handkerchief.
15. The general process of making shell combs differs but little from that which has been just described, varying only in a few particulars, in compliance with the peculiar nature of the material.
16. On account of the great value of shell, the workmen are careful to make the most of every portion of it; accordingly, when a piece falls short of the desired size, it is enlarged by welding to it another of smaller dimensions. The union is effected, by lapping the two pieces upon each other, and then pressing them together between two plates of hot iron. The heat of the iron is prevented from injuring the shell, by the interposition of a wet linen cloth, and by immersing the whole in hot water. In a similar manner, broken combs are often mended; and by the same method, two pieces of horn can also be joined together.