476 Intelligence and Miscellaneous Articles. 



higher temj^erature its composition changes. When it has been 

 melted it does not perfectly solidify on cooling, but remains soft, and 

 may be drawn into threads at common temperatures. It is at first 

 transparent, and then after some time it becomes a mass of radiating 

 crystals. At 50° Fahr. 100 parts of alcohol of 85° dissolve 14-4a. 

 Its composition, as well as that of the hydrates of oil of lemon and 

 bergamot, is as follows : — 



Experiment 



Carbon 63-2 



Hydrogen 

 Oxygen ., 



1000 100-0 100-0 



When hydrate of oil of turpentine is heated to a higher tempe- 

 rature than that at which it melts, it is very rapidly decomposed into 

 •water and a new hydrate, not containing more than two equi- 

 valents of water, and which almost entirely evaporates ; the residue 

 is inappreciable. 



It will be remembered that MM. Blanchet and Sell have found and 

 analysed a substance obtained from oil of turpentine, to which they 

 have assigned the formula C^oH^'H^O'^. In the nomenclature 

 adapted to these series of compounds, the name of monohydrate of 

 oil of turpentine ought to be given, as well as to the product derived 

 from distilling the hydrate obtained from the action of nitric alcohol 

 on oil of turpentine ; M. Deville gives the name oi perhydrute to the 

 crystals collected in moist oil of turpentine or treated with nitric 

 alcohol. 



Heat is not the only agent which is capable of converting the ter- 

 hydrate of oil of turpentine into bihydrate ; the same effect is pro- 

 duced by a dry vacuum. Moreover, the terhydrate is reproduced, 

 when, after having lost, by either mode, 2 equivalents of water, it is 

 left exposed for some time to moist air. This singular reaction is i)ro- 

 bably unparalleled in organic chemistry : it is surprising to observe 

 a substance which is totally insoluble in water, like the bihydrate of 

 oil of turpentine, absorb water from a moist atmosphere, as is shown 

 by the result of quantitative analyses performed with care. 



The following are the results of an analysis of the bihydrate, re- 

 cently prepared by means of many distillations : — 



Experiment. Calculation. (C^^H^^O*) 



Carbon 69-4 69*76 



Hydrogen ... 11-8 11-63 



Oxygen 18-8 18-61 



100-0 100-00 



The density of the vapour confirmed this formula ; by experiment 



it was 6*257, by calculation 6-01 ; the bihydrate possesses no acid 



reaction ; when heated with potash, it is volatilized and does not 



combine "with it, although its composition would lead to the con- 



