278 Dr. Ure on Soda-Alum. 



100.00 58.500 



For certain purposes in calico-printing, this salt seems to be 

 well adapted, by its remarkable solubility in water. That it 

 contains no ammonia, I ascertained, by distilling a portion of 

 its solution, off lime. 



I am. Dear Sir, 



Your most faithful servant, 



Andreav Ure. 



Art. V. A Translation of Rey's Essays on the Calci- 

 nation of Metals, &c. 

 [Communicated by John George Childrivn, Esq., F.K.S., &c.J 

 Concluded from page 141, 

 Essay XXII. 



It is not the volatile salt of the charcoal that increases the 

 weight. 



As soon as I had made the rough sketch of this discourse, 

 I sent it to the person spoken of in the last Essay, who, a few 

 days after, put into my hands a writing, disavowing the opinion 

 which I have there combated; and, after having opposed to 

 my creed respecting the thickening and increasing of weight 

 of the heated air, the reasons which I have related in the 12th 

 Essay, and refuted in that and the two following, he proposes 

 his own opinion briefly as follows : The increase of weight is 

 necessarily derived, either from the vessel, the air, or the 

 charcoal. Not from the vessel, since it loses nothing of its 

 weight; not from the air, since heat can only subtilize and 

 Tender it lighter, as he pre-supposes proved ; it remains there- 

 fore, says he, that it must be the charcoal to which it is owing. 

 And, to show how that happens, he says that charcoal contains 

 two parts or natures, one vegetable, the other metallic; and 

 each of these two parts, one fixed, the other volatile. The 



