The use of various solventa and combinations of solvent materials has been attempted or proposed; e.g. a mixture of camphor and oils in about the following proportions, viz.: Camphor, camphor oil, or liquid camphor .. .. 20 parts by weight.
Oil, auch as castor or linseed, before or aft,er boiling .. 40 77 Pyroxyline (soluble) .. 40 These will give a consiatency suitable for covering telegraph wires, or for moulding or spread ing. For material with greater or less flexibility, or greater or less fluidity, the proportion or character of the oil must he changed. In producing very hard or rigid material, it ia preferable to uso oils which will themselves harden by expoaura to air, aa those which have been boiled. Camphor may also he used in about equal proportions with hydrocarbons having a boiling-point at 104°-204° (220°--400° F.); or with alcohol or spirits of wine ; or hydrocarbons in equal proportions with aleohol ; or castor oil in equal proportions with alcohol ; or a distillate of a mixture of camphor oil and hydrocarbons, or of camphor and bisulphide of carbon in conjunction with alcohol ; or aldehyde, either alone or with alcohol. Either of these aolventa may be employed with the other ingredients iu about the following proportions, to produce a aemi-fluid celluloid : Pyroxyline (soluble) .. 27 parts by weight.
Castor oil .. .. 27 77 Camphor .. 6 71 Either of the foregoing solvents .. 40 17 The consistency will depend chiefly on the proportions of the oil, as before.
Tbe most recent and valuable improvements in the manufacture of celluloid, for all manner of purposes, will be found in two patents (Nos. 1865 and 1866) taken out, in May last, by Henry Parkes, a relative of the first European discoverer of the substance.
Uses.It is only fair to premise that, in the following aketch of some of the applications of celluloid, no pretence is made to exhaust the list. It possesses such a combination of valuable properties that its sphere of usefulneas must of necessity he enlarged, as the article becomes more generally known and appreciated, and as further shwa are made in the direction of controlling its rather combustible tendencies under climatic changes. Nevertheless, it will be seen from the sequel that it has already attained a high degree of importance. It ia superior to ivory on the acore of durability, as it sustains hard blows without injury, and never loses its colour. One whole company in the United States employ it exclusively for organ and piano keys, and its con sumption for that and similar purposes haa assumed such proportions that ivory is much reduced in price in consequence. Billiard halls can he made from it at half the cost of ivory, while possessing equal elasticity and greater durability. It is extensively employed for making combs, brush backs (see Brushes), and various other toilet things wherein ivory has hitherto been used.
For small-tooth combs, the cost is 25 per cent. less than ivory, an in large pieces, the difference is enormous. It effectually displaces ivory, too, in harness trimmings, foot-rules, chessmen, and handles of various kinds, especially knife and fork handles, fir which purposes it is admirably adapted, as it neither cracks nor becomes discoloured by hot water. Incilaruhber generally holds its owu in competition with celluloid, on account of the relative prices ; but the latter is much more durable, and is superior for pencil-cases, jewellery, &c., where gold mountings are used, as it does not tarnish the metal, where,as the sulphur in indiarubber tarnishes all gold under 18 carat. This freedom from sulphur, and the readiness with which it takes a natural flesh-tint, have caused cellu loid to he used for dental blanks or gum, and other attachments of artificial teeth, in lieu of vulcanized indiarubber. It can be mottled to imitate the finest tortoiaeshell, and its elasticity renders it less liable to fracture. In thia form, it is much used for combs, card and cigar cases, match-boxes, pocket-books, napkin-rings, ancl all sorts of fancy articles. It can be made to resemble malachite and amber equally well, and is very suitable for the mouth-pieces of pipes, cigar-holders, flutes, flageolets, &c. For drum-heads, too, it is better than parchment, as it is not affected by moisture. It replaces porcelain in the manufacture of dolls' heads, which are practically unbreak able. Coral of all shades can be copied exactly, but dark or bright red, and not the rare and costly delicate pink shade, are mostly in demand For optical goods, such as the frames of spectacles, eye and opera-glasses, it competes successfully with jet, tortoiseshell, 8c-c. ; and for photographic purposes, it is superior to ivory. It ia used for shoe-tips inatead of metal, and has the appearance of patent leather ; it is also employed in in-soles. Many thimbles are made of it ; and it is said to be the best material known for emery-wheels and knife-sharpeners. Within this last eighteen months or so, a new demand has arisen for the substance, as a substitute for linen or paper in shirt-fronts, cuffs, and collars. It looks like well-starched linen, is sufficiently light and flexible, does not wrinkle, ia not affected by perspiration, and can be worn for months without injury. It soils less readily than linen, and, when dirty, is quickly cleaned with a little soap and water on a flannel. A more recent improvement consists in placing real linen between two sheets of celluloid. It has also been tried for neckties. For hatbands and hat sweat-bands, it is dearer than the articles in present use ; but it is much superior, as it does not become rusty or greasy.