CAMPHOR. 899 



CAMPHOR. 



Formula: C 20 H 16 O 2 , or C 20 H 14 -f2HO. This essence is 

 brought to Europe chiefly from Japan ; it is obtained by dis- 

 tilling the wood of the Laurus camphora along with water, and is 

 refined by a second sublimation. It is in white translucent 

 crystalline masses, somewhat tough, but easily pulverised when 

 moistened with alcohol ; possessing a peculiar taste and smell, 

 and may be obtained in brilliant crystals of a high refracting 

 power, either by sublimation or from solution in alcohol. It 

 floats upon the surface of water, its density being from 0.985? 

 to 0.997 ; fuses at 347, and boils at 399.2 (204 centig.) ; the 

 density of its vapour is 5317- It evaporates at the usual tem- 

 perature, a property that contributes to produce the lively 

 movements which small pieces of camphor exhibit upon the 

 surface of pure water. Like all the essential and fat oils, it also 

 possesses a remarkable tendency to diffuse a thin film of its sub- 

 stance over the surface of water, the result of a kind of capillary 

 attraction, in consequence of which a little column of camphor 

 rising out of water is in the course of a short time cut across at 

 the surface of the liquid. The detaching of the substance of the 

 camphor by this force must occasion a recoil, which appears to 

 be the principal cause of the movements of a floating mass. All 

 movement ceases when a drop of any oil is allowed to fall upon 

 and diffuse over the surface of the water. Camphor is easily 

 kindled, and burns with a white flame. It is but slightly 

 soluble in water, one part of camphor requiring about 1000 parts 

 of water to dissolve it ; but the solution has the taste and odour 

 of camphor. It is largely dissolved by alcohol, ether and oils. 

 The solution in proof spirit, known as camphorated spirit, is 

 precipitated by water. Camphor forms liquid compounds with 

 nitric acid, acetic acid and hydrochloric acid. When distilled 

 with anhydrous phosphoric acid it loses 2HO, and yields a 

 pure hydrocarbon, C 20 H 14 , to which M. Dumas applied the name 

 camphogen. 



Camphogen, after being distilled repeatedly from phosphoric 

 acid, is a colourless liquid, of density 0.86L at 57-2, and boiling 

 at 347. The density of its vapour is by experiment 4/80; by 

 calculation 4697, allowing its combining measure to contain 



2 N N 2 



