176 PHILOSOPHICAL TRANSACTIONS. [ANNO 1782. 



tion what passed over was merely water ; this being poured out of the receiver, 

 the fire was increased ; but what rose up in distillation was not acid, nor did it 

 decompound saccharum saturni. 



Exp. 114. White Arsenic. Equal quantities of white arsenic and Segner's 

 salt of rather a yellowish colour, were triturated together into a powder, and in 

 order to promote their action on each other, 2 drs. of distilled water were added, 

 and the mixture was digested with a gentle heat. In about a quarter of an 

 hour, part of the powder or mass turned black, and adhered strongly to the 

 sides of the vessel in the form of a black, circle. Being afterwards subjected to 

 distillation, only a small quantity of fluid was obtained, and that had no acid 

 taste, nor did it give a precipitate when added to sugar of lead. 



Exp. 1 15. Nitrated Cobalt. One drachm of Segner's salt was added to 4- oz. 

 of a nitrous solution of cobalt, and the mixture was subjected to distillation, 

 till all the fluid part was drawn off. The exsiccated salt in the retort was of a 

 green colour, and when cold turned white; -being dissolved in distilled water, it 

 exhibited a new species of sympathetic ink, not unlike the common sympathetic 

 ink from cobalt, but inclining more to a yellow colour. 



Exp. 11 6. Sal ammoniacum animale. Of the animal sal ammoniac (com- 

 pounded of acid of fat and volatile alkali) 1 drs. were mixed with 15 grs. of the 

 lapis haematites, and the mixture was subjected to sublimation ; when the opera- 

 tion was over, it was found that the sal-ammoniacum animale had sublimed un- 

 changed, while the lapis haematites remained at the bottom of the retort. The 

 result was the same when the operation was repeated with the addition of a 

 small quantity of water. 



The action of the acid of fat on neutral salts. — Exper. 117. Nitre. Two dr. 

 of the acid of fat being poured upon 1 dr. of purified nitre, the latter was dis- 

 solved with some degree of effervescence or commotion. No sooner was the 

 retort piaced in the sand bath, than it was seen to be rilled with a yellow vapour, 

 the colour of which grew darker and darker till at length it turned red. The 

 fluid in the receiver had the taste of the nitrous acid, with some admixture of 

 the taste of the acid of fat; and its action on silver showed that it did not consist 

 of pure nitrous acid. 



Exp. 118. Common Salt. Two drachms of this salt were dissolved in an 

 equal weight of the acid of fat. Towards the end of the distillation, grey 

 vapours were distinctly seen ; and when the distillation was finished, the smell of 

 the fluid in the receiver was the same as the smell of the muriatic acid ; and he 

 was induced io believe, by subjecting it to other tests, that the fluid in the re- 

 ceiver was the muriatic acid. 



Exp. 110. Terra foliata tartari. The acid of fat being added in equal quan- 

 tity to the terra foliata tartarj, a slight effervescence ensued ; being subjected to 



