CELLULOID (Lat. cellula, little cell, dim. of rel)a. cell). A substance of modern invention id(bl• 11..141 in the arts as a substitute for ivory, india -rubber, and leather, and, for many other pur tel was first made in England by a Mr. Parkes, of Birmingham, in l$56,. and was given at first the name park(sinc. its manu facture was developed in America by John W. Hyatt. of Newark, N. .1., in !tin!), who is said to have made the invention independently. Cel luloid is obtained by mixing gum camphor with pyroxlin (guncotton pulp) in the proportion of about two parts of p3roxylin to one of cam phor. The usual process is to dissolve the cam phor in the least possible quantity of alcohol and sprinkle it over successive layers of the dry pyroxylin, until the desired thickness is reached. The mass, thus treated, sinks into transparent lumps and in this form is worked for an hour between cold rollers, and then between rollers are slightly heated. The mass is next,
subjected to hydraulic pressure for twenty-four hours in a room kept at a temperature of TO° F. It is then cut into sheets of the desired thickness and allowed to dry for fourteen days, when it is ready to be manufactured into articles. It is also manufactured in the form of a liquid coat ing to be applied to other materials, such as cot ton. linen, or paper. or for use in other ways. Any color can be given to celluloid by the use of coloring matter during the process of manu facture. Sonic of the advantages of celluloid, besides its cheapness and durability, are that it take-. a high polish, does not warp or discolor, and is impervious to moisture. As ordinarily manufactured, it is highly inflammable.