38 Mr. Stenhouse on the Action of Peroxide of Lead 



tallic communication between it and the prime conductor of 

 an electric machine, then charge the whole powerfully with 

 electricity, and the liquid will now flow through the minutest 

 capillaries, and this without any risk of rupturing these fine 

 vessels. 



[To be continued.] 



VI. On the Action of Peroxide of Lead on Cinnamic Acid 

 and on Salicine. By John Stenhouse, Esq.* 



IT is well known that when cinnamic acid is digested with 

 nitric acid, oil of bitter almonds is formed, which is easily 

 recognisable by its smell, and the cinnamic acid is converted 

 into the benzoic acid. If strong nitric acid is employed, how- 

 ever, and the digestion is long continued, the benzoic acid is 

 still further resolved into the nitro-benzic acid of Mulder. 

 I was induced to try if peroxide of lead would also have the 

 effect of converting cinnamic into benzoic acid. On boiling 

 a solution of cinnamic acid with peroxide of lead, the smell 

 of oil of bitter almonds was immediately emitted, and the per- 

 oxide of lead became of a light ochre colour. This change 

 of colour was owing to the reduction of the peroxide of lead 

 to the state of protoxide. In order to determine with what 

 acid the lead had combined, the salt was decomposed with di- 

 lute sulphuric acid, and the organic acid thus set free was 

 purified by repeated crystallizations. It had all the external 

 characters of benzoic acid. The following are the results' of 

 its analysis : — 



gramme. 

 i. 0*2879 substance gave 0*725 carbonic acid, and 0*1320 

 water. 



ii. 0*2885 substance gave 0*7295 carbonic acid, and 0*129 

 water. 



I. ij. Calculated numbers. 



C 69*62 69*91 69*27 



H 5*07 5*00 4*84. 



O 25*31 25*09 25*89 



100*00 100*00 



Now these approach pretty nearly the calculated numbers 

 for hydrated benzoic acid, the formula for which is 



C 14 = 69*27 per cent. 

 H 6 = 4*84. 

 O 4 = 25*89 



* Communicated by the Author. 



