304 Prof. A. W. Hofmann on the Transformation of the Mar. 19, 



nearly insoluble in water, which is obtained when the ammonium-salt is de- 

 composed by nitrate of silver. Its composition is 



C„H,AgO,. 



The harium- and calcium-salts are crystalline compounds, difficultly 

 soluble in water, easily obtained by double decomposition, and purified by 

 crystallization from boiling water. 



The barium-salt forms white needles which, when dried in vacuo, exhibit 

 the composition 



At 110° the salt loses its water. 



The calcium-salt also crystallizes in needles. The analysis of the vacuum- 

 dry salt led to the formula 



S^Ca-g:} + 2H,0. 



At 110° the salt becomes anhydrous. 



The copper-salt and the lead-salt are respectively green and white pre- 

 cipitates. 



Highly characteristic is the deportment of the acid when it is submitted 

 to the action of caustic baryta. Faithful to the traditions of benzoic acid, 

 menaphthoxylic acid splits into carbonic acid and naphthaline, 



C,H.O, = C,„H, + CO,. 

 The naphthaline thus obtained possesses the fusing-point, and the properties 

 in general of the hydrocarbon formed in the distillation of coal. 



Menaphthoxalate of calcium, when submitted to the action of heat, yields 

 an aromatic distillate which gradually solidifies to a crystalline mass, pro- 

 bably the ketone of the series. 



Nitric acid gives rise to the formation of a beautiful nitro-acid ; when 

 boiled with very concentrated acid, menaphthoxylic acid is transformed into 

 a difficultly soluble crystalline compound which is no longer acid. 



Some experiments on the chloride corresponding to the acid, and some 

 of the derivatives of the chloride, may still be briefly here recorded. 



On mixing four parts of menaphthoxylic acid (fused and powdered after 

 solidification) with five parts of pentachloride of phosphorus, the two com- 

 pounds begin to act upon each other at the common temperature. The 

 mixture becomes liquid, and disengages, when gently heated, abundant 

 quantities of hydrochloric acid and oxychloride of phosphorus. The boil- 

 ing-point of the liquid rapidly rises to 300° What distils between 296° 

 and 298° is the pure chloride of menaphthoxylic acid, the boiling-point of 

 which is pretty accurately 297°'5. Menaphthoxylic chloride is a hquid at 

 the common, a solid at low temperature ; it has the composition 



C,, H.OCl, 



and exhibits the deportment of the aromatic chlorides in general. When 

 exposed to the atmosphere it absorbs moisture, being gradually transformed 



