ON LANI> ANi5 SEA- AIR. 267 



could contain was equal to the hundred divisions of the 

 graduated fcale. 



My water trough on board of the fhip was the com- 

 mon v.'ater bucket ; on lliore it was a common houfe 

 bucket or tub. 



1 he nitrous gas was prepared from diluted nitric acid 

 and brafs filings. 



At fca 1 ufed fea water in the trough ; on land com- 

 mon piunp water: for from diiferent trials made by 

 Dr. Inffenhoufz it is evident this circumftance could not 

 produce :i variation in the reiult of the experiments. 



My method of operating is as follows : After having 

 introduced two mealures of the air, whofe purity I de- 

 fired to afcertain, into the glafs tube, I introduce one 

 meafure of nitrous gas ; then, fuifering the tube to remain 

 undifturbed for about a minute, I noted down how far 

 the water afcended without agitation ; this is what 1 have 

 called, upon mixture : I then agitated the tube three fuc- 

 ceflive times, after the manner of M. de SaulTure, and 

 noted how high the water rofe. In many inftances I 

 added a fccond meafure of nitrous gas, and thereby com- 

 pletely faturated the air under examination. 



I was particularly cautious of avoiding miftakes from 

 hurry or inattention, and took fome pains to guard 

 againft all the circumftances Dr. Ingenhoufz mentions 

 as liable to produce a variation in the refult of experi- 

 ments of this kind. 



My firft experiment on land air was performed Au- 

 guft id, ^796. Two meafures of air in the yard of my 

 lodging, when mixed with one meafure of nitrous air, left 

 upon mixture 2.48 of a meafure ; and after Ihaking the 

 tube 1.79. I then added another meafure of nitrous air 

 and 2.6s remained, 



I then fubrnltted air to the teft of the eudiometer which 



I had previoufly colledted in different fireets of this city, 



3 viz. 



