MARSH AIR. 419 



del Cane and other fimilar places, prove that the gravity of 

 this elaflic fluid permits it to rife but to an inconfidcrable 

 height. 



After having proved that certain qualities do exift in the 

 air over marflies, v/hich are different from thofe pofTeircd by 

 the atmofphere in other fituations, v?e muft next attend 

 to our 



Second objedt, viz. to afcertain what are the circum- 

 ftances about marfhes which produce fuch efFeds ? 



Before we proceed any further, it is of the greateft im- 

 portance to be iatisfied refpeCling the changes which may 

 be produced on common atmofpheric air, when fubjedlcd 

 to the adion ot the ibil of marllies. 



At different times in the months of September and the 

 commencement of October 1796, 1 expofed atmofpheric 

 air to the adlion of mud, whicfi I obtained from marllies 

 below the city. The fame was done at different times in 

 the months of April and July, 1798. The experiments 

 were expofed to the temperature of the atmofphere. The 

 refuks from the different experiments were fimilar. The 

 air was expofed to the adlon ot the mud which was con- 

 tained in a tumbler, by means of an inverted glafs jar, in 

 a bafon containing a fmall quantity of water. The follow- 

 ing changes were noticed. 



1. The air contained in the jar became much diminifli- 

 ed in bulk, as was proved by the water riling into the jar. 



2. The air, thus afted upon, when agitated v^rith lime 

 water, afforded a copious white precipitate and became di- 

 miniflied in bulk. 



3. In fome of the jars, were fufpended papers, ftained 

 blue with litmus and yellow with turmeric, the blue re- 

 ceived a reddiih tinge and the yellow remained unaltered ; 

 the red was again changed to a blue by expofure to the va- 

 pour iffuing from a bottle containing ammoniac. 



4. The air thus altered by the mud, when mixed with 

 nitrous gas in the eudiometer tube, was in every inftance 



3 I 2 found 



