392 Scientijic Intelligence. [May 



IX. Camphor. 

 The peculiar characters of camphor are well known to 

 chemists. Its great volatiUty, its strong smell, its fusibility 

 when heated, its solubility in nitric acid, and in alcohol. In some 

 respects it resembles the volatile oils ; but the nondecomposition 

 of it by nitric acid, except when we employ a great deal of acid, 

 and assist the action by heat, sufficiently distinguishes it from 

 these bodies. It melts, when heated to 288°, and boils at the 

 temperature of 400°. 



I had the curiosity to analyze it by passing it slowly through 

 red-hot peroxide of copper. By this process it was converted 

 into carbonic acid and water. The first of these I collected over 

 mercury and measured, while the second was intercepted by 

 means of muriate of lime, and the quantity of it was made known 

 by the increased weight of the salt. One grain of camphor, 

 vvhen thus treated, yielded 5*837 cubic inches of carbonic acid 

 gas under the mean temperature and pressure, and 1-3 gr. of 

 water. Hence the constituents of camphor are : 



Carbon in carbonic acid 0'738 



Hydrogen in water ()"144 



Oxygen (to make up the deficiency) . . 0-U8 



1-000 

 This approaches very nearly to 



8,} atoms carbon ....== 6'375 .... 73'iJl 



10 atoms hydrogen .. = 1-250 .... 14-49 



I atom oxygen = 1-000 11-60 



8-625 100-00 



X. Prussiute of Iron. 



The nature of prussiate of iron not being hitherto determined 

 in a satisfactory manner, I made some time ago the following 

 experiments on it, which appear to me to explain its composition 

 pretty completely. A quantity of pernitrate of iron was preci- 

 pitated by prussiate of potash, and the deep blue precipitate was 

 collected on a filter, well washed, and dried in a temperature not 

 above 150°. It is well known that this salt catches fire and 

 burns with the emission of a great quantity of ammonia, when 

 exposed to a heat not greatly exceeding 212"^, It cannot, there- 

 fore, be completely freed from water by heat ; but as there is no 

 great difficulty in determining the weight of the peroxide of 

 iron, and o£the ferrochyazic acid which the powder contains, I 

 consider the presence of a Uttle moisture as of no great conse- 

 quence, 



1. To determine the quantity of peroxide of iron, I digested 

 20 gr. of the prussiate of iron in potash ley diluted with water 

 over a sand-bath for 24 hours. The liquid was then drawn off, 

 and the red sediment carefully washed and dried. It weighed 

 7"56 gr. and was pure peroxide of iron. 



