62 SCIENCE PROGRESS 



camphor comes into the market in three forms — as "flowers," 

 obtained by condensing the sublimed camphor in a chamber; as 

 " bells," which are hollow transparent domes of camphor, 

 weighing usually from 2 to 6 lb., and made by subliming in glass 

 retorts ; and as " blocks," obtained by subjecting the flowers to 

 strong pressure. It is in this last form that one is accustomed 

 to see camphor. A by-product in the extraction of camphor is 

 the " camphor oil," which contains many essential oils as well as 

 camphor in solution. 



Properties and Uses 



Camphor is a colourless crystalline substance melting at 

 175 C, but is volatile even at ordinary temperature. It has a 

 characteristic odour which is said to be detectable at a dilution 

 of '000005 gram of camphor in 1 litre of air. It is readily 

 inflammable, burning with a smoky flame. In water camphor 

 is almost insoluble, one part of camphor requiring about 1000 

 parts of cold water for solution (aqua camphors). In all organic 

 solvents it dissolves with ease. Japanese camphor has a strongly 

 dextro-rotatory action on the plane of polarised light — a [D] in 

 alcoholic solution ± 44*2°. The laevo-rotatory camphor occurs in 

 nature in the oil of Matricaria parthenum, and is known as 

 matricaria camphor. With the exception of its opposite rotatory 

 power it is identical with ordinary Japan camphor. 



Camphor finds application chiefly in three directions : 



1. In pharmacy. Camphor is used in more than thirty 

 different forms. It is antispasmodic, a stimulant, cardiac, and 

 local anodyne, and is used in fevers, hysteria, dysmenorrhea, 

 colic, etc. The familiar " camphorated oil" is a solution of one 

 part of camphor in about four parts of olive oil. 



2. In explosives. The use of camphor in explosives would 

 appear to be somewhat limited. It exercises a preservative 

 action on blasting gelatine. 



3. In the manufacture of celluloid (xylonite). This industry 

 consumes the greater part of the camphor produced. Celluloid 

 was invented in 1869 by Daniell Spill in England and by Hyatt 

 in America. The process of manufacture, expressed in a few 

 words, consists of the incorporation of camphor with nitrocellulose 

 {pyroxylin, collodion wool, guncotton) and a suitable solvent 

 such as acetone. The enormous number of articles now made 

 of celluloid indicates what a large quantity of camphor must be 



