$6 Account of a new Eudiometer, 



tions of fuch men, who abound in no other country, we 

 owe one of the proudeft diminutions of our national cha- 

 racter — that of being- an enlightened and an enterprifing 

 people. 



IX. An Account of a new Eudiometer, By Mr. Davy** j 



X HE dependance of the health and exigence of animals 

 upon a peculiar ftate of the atmofphere, and the relations of 

 this ftate to procefTes connected with the mo ft eflential wants 

 of life, have given interefl and importance to inquiries con- 

 cerning the competition and properties of atmofpheric air. 



This elaftic fluid has been long known to contift chiefly 

 of oxygen and nitrogen mingled together, or in a Mate of loofe 

 combination, and holding in folution water. 



A variety of procefTes have been inftituted with the view 

 of determining the relative proportions of the two gafes, but 

 moft of them have involved iburces of inaccuracy; and lately 

 all, except two (the (low 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 oxygen of atmofpheric air at common tem- 

 peratures, and ihey do not materially alter the volume, or the 

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

 tremely (low, and in many cafes it is difficult to afcertain the 

 period at which the experiment is completed. 



I have lately employed as an eudiometrical fubftance the 

 folution of green muriate, or fulphate, of iron, impregnated 

 with nitrous gas; and I have found that it is in fome refpecls 

 iuperior to many of the bodies heretofore ufed, as it rapidly 

 condenfes oxygen without acting upon nitrogen, and requires 

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

 paratus. 



This fluid is made by tranfmitting nitrous gas through 

 green muriate, or fulphate, of iron, diflblved to. iaturation in 

 water f. As the gas is abforbed, the folution becomes of a 

 deep olive-brown, and when the impregnation is completed it 

 appears opaque and almoft black. The procefs is apparently 

 owing to a fimple elective attraction; in no cafe is the gas 

 decompofed; and under the exhaulled receiver it affumes its 



;: From the Journals of the Royal biftituiion of Great Britain, vol. i. 

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

 it, fee Keftarcjics, Chemical aiul Piiilofophical, p. 152. johnfon. . 



elaftiq 



