192 M. Limpricht on some Compounds of Salicylic Acid, 



mulse^ where chemistry does not herself possess the means of 

 fixing these weights and these formulae in a relatively certain 

 manner. But formulse which only express a relation concerning 

 a single physical quality cannot be accepted as chemical formulse, 

 especially if they disagree with indubitable chemical analogies. 



Reynoso proposed a method for the determination of phos- 

 phoric acid, which consisted in combining the phosphate with a 

 known quantity of metastannic acid. By subtracting from the 

 weight of the compound of phosphoric acid and metastannic acid 

 formed, the metastannic acid used, the quantity of the phosphate 

 is obtained. Although an excellent method, it has many diifi- 

 culties which hinder its application. To remove these, and to 

 make the method applicable to all cases, Reissig* proposes a 

 modification of it, which consists in separating the phosphoric 

 acid from the metastannic acid, and determining it directly as 

 phosphate of magnesia and ammonia. 



Schlossberger^t has detected crystals of oxalate of lime in the 

 Malpighian vessels of the spider. 



Piria has lately shown that salicylic acid is bibasic. From 

 this point of view Limpricht J has submitted several compounds 

 of this acid to an investigation. Salicylamide, regarded as 



H >N, must be considered, on the bibasic view, as sali- 

 H J 

 cylamic acid, ^ „ ^ >0^, and Limpricht has prepared 



several of its salts. By the action of heat, salicylamic acid loses 

 2 equivs. of water, and is converted into salicylimide, 

 Ci4H7N04-2HO = Ci4HSN02. 



The sethyle- salicylamic acid was also obtained by the action of 

 ammonia on methylsethyle salicylic aether. Limpricht is still en- 

 gaged in the investigation. 



Kolbe § describes a new method for the formation of benzoic 

 aldehyde. Since the researches of Chiozza and Gerhardt, the 

 existence of compound radicals containing oxygen has been placed 

 out of doubt, and the benzoyle theory of Liebig and Wohler is 

 again generally received. According to this, benzoic acid, chlo- 

 ride, hydruret, and cyanide of benzoyle are compounds of the 

 radical benzoyle, C'^ H^ 0^, or (C^^ H'^) C^ 0^. 



If, now, the hydrogen in hydruret of benzoyle, C^'* H^ 0*, H, 



* Liebig's Annalen, June, p. 339, t Ibid. vol. xcviii. p. 354. 



X Ibid. May, p. 256. § Ibid. June, p. 344. 



