M. Piria on Populine. 377 



Its formula is C'o H^^ 0'« f 4H0, and it loses the water at 100° C. 

 It is to be considered as composed of benzoic acid, saligenine, and 

 grape-sugar: — 



C40 H22 Qi6 ^ 4H0 =C>4 RS 0^ + C" H4 0* + C12 H'2 Qi^ 



» Y ' Benzoic acid. Saligenine. Grape-sugar. 



Populine. 



Salicine is composed of saligenine and grape-sugar, and when 

 treated with acid is resolved into saliretine and grape -sugar. Simi- 

 larljf, populine, when treated with acid, splits up into benzoic 

 acid, saliretine, and grape-sugar. 



It was thought that if the benzoic acid could be separated 

 from the populine, salicine would be formed. By the action of 

 caustic baryta this is effected, and the salicine separated has also 

 the physical and chemical properties of that prepared in the usual 

 way. The benzoic acid formed corresponds with the quantity 

 required by theory. 



By treating salicine with nitric acid, helicine is produced. In 

 the same way, by treating populine with nitric acid, benzo-helicine 

 is formed. And from this benzo-helicine, by the action of caustic 

 magnesia, helicine is produced, which is exactly the same as that 

 produced directly from salicine. 



Helicine is decomposed by acids into grape-sugar and hydride 

 of salicyle; and benzo-helicine similarly into benzoic acid, hydride 

 of salicyle, and grape-sugar. 



Piria considers at length the conditions under which bodies 

 form copulated compounds. When these copulated compounds 

 split up, the elements of water are always assimilated, and in 

 the formation of these copulated compounds water is eliminated. 

 He proposes this law, that when n constituents unite to form a 

 copulated coiypound, S(n — 1) equivalents of water are eliminated. 

 Thus in the copulation of two bodies =2, of 3=4, of 4=6, 

 of 5 = 8. Piria considers populine an example of the copulation 

 of three bodies, and here 4 equivs. of water arc separated. Amyg- 

 daline is considered by Piria as containing five groups of atoms, 

 in the copulation of which 8 equivs. HO arc separated. 



By acting on glycerine with iodide of phosphorus, Berthelot 

 obtained a new body, the iodide of propylenyle, C'H^I. The 

 discovery of this body has lately led to numerous important results. 

 It occupies the same place in a new series of alcohols as iodide 

 of aithylc does in the common alcohol series. By distilling it 

 with sulphocyanide of potassium, Berthelot and Ue Luca, and 

 independently of them, Zinin, obtained the artificial oil of mus- 

 tard, C^ N S^K -i- C« H'^ I = C« H5 C2 N S'^ By acting with it on 

 acetate and licnzoate of silver, Zinin has obtained compounds 



Phil. May. S. 4. Vol. 1 1. No. 73. May 1856. 2 C 



