374 0» tkt Letompbjtlion of Muriatic Acid. 



that the mud of the Nile contains fome remains of vegetable fubftances ; fo that, when it is 

 diftilled a certain quantity of carbonic acid and of carbonated hydrogen gas is obtained. 



Chaptal repeated them at Montpelier, without obtaining abforption. 



I have kept moift alumine for a confiderable time in conta£t with atmofperic air and 

 oxigen gas, without obferving the lead abforption. It having been mentioned by a chemift 

 that abforption was caufed by agitation ; the effeiSl of agitation was patiently tried, but the 

 refult was always the fame. The operation has been renewed with the white clay which 

 had been fent to me by Guyton, but it alfo produced no abforption. This clay, neverthe- 

 lefs, when urged by the fire, yielded a little carbonic acid and a fmall quantity of carbo- 

 nated hydrogen gas. 



IX. 



On the Decompofition of the Muriatic Acid. By Mr. John PtTCHFORD, Junior. 



I 



To Mr. NICHOLSON. 

 SI R, 



F you think the following obfervations of fufEcient importance, you will oblige me by In- 



ferting them in your ufeful mifcellany. 



I am, Sir, 



Your's, &c. 



Norwich, Aug. \6, 1800. JOHN PITCHFORD, Jun. 



I have long confidered the analyfis of the muriatic acid to be a point of the firft import- 

 ance in the prefent ftate of chemical knowledge. Among many experiments to afcertain 

 its compofition, which have occurred to me, one was founded on Dr. Fordyce's experiments, 

 recorded in the Philofophical Tranfadlions for 1792, the objeft of which was to difcover 

 whether, in the folution of zinc in dilute fulphuric acid, the metal derives the oxygen 

 neceflary to render it foluble from the acid, or from the water. The refult of a feries of 

 very accurate experiments is well known to have been, that the water furnifhes the whole 

 of the oxygen, and that no portion of the acid is decompofed. The proof of this is that 

 it requires as much pot-afli to precipitate the zinc from a certain quantity of acid as to fatu- 

 rate an equal quantity of acid in which no zinc has been diflblved. 



Wifhing to afcertain whether this would alfo be the cafe with muriatic acid, I diflblved 

 one ounce of tin in four ounces of this acid of fpecific gravity, 11 78. During the folution 

 a confiderable quantity of hydrogen gas was evolved. When the folution was completed 

 I added pot-afli till the whole of the tin was precipitated, and the acid faturated, which took 

 place when 1412 grains of pot-afh had been added. I next tried how much pot-afn four 

 ounces of the fame muriatic acid would require for faturation, and found that 17 17 grains 

 were required. Now allowing that fome fmall portion of the muriatic acid, may have 



been 



