ACCOUNT OF A NEW EUDIOMETER. 4i 



IX. 



An Account of a neiu Eiidiojncter.'* By Mr. H. Davy, Director 

 of the Chemical Laboratory, and Leclurer on Chemijlry to the 

 Royal Injlitulion. 



JL HE dependance of the health and exigence of animals upon Competition of 

 a peculiar Hate of the atmofphere, and the relations of this the . atmof P he « 

 ftate to procefles connected with the molt eflential wants of life, fubjecl. 

 have given intereft and importance to inquiries concerning the 

 composition and properties of atmofpheric air. 



This elaftic fluid has been long known to confift chiefly of Oxigen and ni- 

 oxigen and nitrogen, mingled together, or in a Hate of loofe tro S en » 

 combination, and holding in folution water. 



A variety of procefles have been inftituted with the view The eudiometric 

 of determining the relative proportions of the two gafes, but mon j y u f C( j ar g 

 moft of them have involved fources of inaccuracy ; and lately exceptionable, 

 all, except two (the flow combuftion of phofphorus, and the 

 action of liquid fulphurets), have been generally abandoned. 



Both phofphorus and folution of fulphuret of potafh abforb 

 the whole of the oxigen of atmofpheric air at common tempe- 

 ratures, and they do not materially alter the volume, or the 

 properties of the refidual nitrogen ; but their operation is ex- 

 tremely flow ; and in many cafes it is difficult to afcertain the 

 period at which the experiment is completed. 



- I have lately- employed as an eudiometrical fubflance the Solution of rau- 

 - folution. of green muriate, or fulphate, of iron, impregnated "/ j^n* hnpreg! 

 with nitrous gas ; and I have found that it is in fome refpects nated with ni- 

 fuperior to many of the bodies heretofore ufed, as it rapidly jj^J toabforb 

 condenfes oxigen without acting upon nitrogen; and requires oxigen. 

 for its application only a very Ample and a very portable ap- 

 paratus. 



This fluid is made by tranfmitting nitrous gas through green How made, 

 muriate, or fulphate, of iron, diflblved to faturation in watert. 

 As the gas is abforbed, the folution becomes of a deep olive 

 brown, and when the impregnation is completed it appears 



* Journals of the Royal Inft. p. 45. 



f Dr. Prieftley firft obferved this procefs : for a particular account 

 of it, fee Refearches, Chemical and Philofophical, p. 152. johnfon. 



opaque 



