M A R S H A I R. 425 



I. That hydrogen gas would be dileiigagcd. 2. That 

 the oxygen combining with the carbone would form the 

 carbonic acid gas. 3. That azote would unite with a por- 

 tion of hydrogen and thus produce ammoniac; whilft an- 

 other portion of it would, during its combination with ox- 

 ygen, form the nitric acid. And 4th. That when fulphur 

 or phofphorus were prefent, they with hydrogen would 

 form the fulphurated and phofphorated hydrogen gafes. 



We fhall now endeavour to difcover whether or not thefe 

 elaftic fluids enter into the compofition of the atmof- 

 phere of marfhes. 



1. Hydrogen gas. Dodlor Franklin has long fince de- 

 monftrated the produdion of this elaftic fluid in marlhy fi- 

 tuations. Ingenhoufz and others have confirmed the truth 

 of his experiments and obfervations. 



My experiments convince me that it is produced in a 

 coniiderable quantity, and that it may be eafily procured 

 by agitating ffagnant waters over marfhes. It is alfo evi- 

 dent that this gas is in a flate of mixture with the carbonic 

 acid gas. 



Although we are certain that a large quantity of hydro- 

 gen gas is difengaged from marfhy grounds, we muft ne- 

 verthelefs conclude that it bears but an inconfiderable pro- 

 portion to the atmofphere at large ; for we find that the air 

 immediately above marfhes will not explode upon the ap- 

 proach of a candle : indeed from its levity we might fup- 

 pofe that it occupies the inferior flrata of the atmofphere 

 but for a fhort time. 



2. Carbonic acid gas. That this elaftic fluid enters large- 

 ly into the compofition of the atmofphere of marflies, is 

 eafily proved by agitating it with lime water. 



3. Ammoniacal gas. The production of this gas dur- 

 ing putrefaftion, is proved beyond doubt ; therefore that 

 it fhould exift in the atmofphere of marflies feems at leaft 

 probable, indeed many have inferred confiderable effedls 



3 K from 



