[ 2I 7 I 



any kind of air that has been diminimed, and ren- 

 dered noxious by any other procefs ; but when it 

 is put to a quantity of nitrous air, it dimi- 

 nifhes it fb much, that no more than one fourth 

 of the original quantity will be left. The efFe£fc 

 of this procefs is generally perceived in five or fix 

 hours, about which time the vifible effervefcence 

 of the mixture begins ; and in a very fhort time 

 it advances fo rapidly, that in about an hour almoft 

 the whole effect will have taken place. If it be 

 fuffered to ftand a day or two longer, the air will 

 ftill be diminifhed farther, but only a very little 

 farther, in proportion to the firft diminution. The 

 glafs jar, in which the air and this mixture have 

 been confined, has generally been fo much heated 

 in this procefs, that I have not been able to 

 touch it. 



Nitrous air thus diminifhed has not the peculiar 

 fmell of nitrous air, but fmells juft, like common 

 air in which the fame mixture has flood; and it 

 is not capable of being diminifhed any farther, by 

 a frefh mixture of iron and brimflone. 



Common air faturated with nitrous air is alfo 

 no farther diminifhed by this mixture of iron 

 filings and brimftone, though the mixture fer- 

 ments with great heat, and fwells very much 

 in it. 



Plants die very foon, both in nitrous air, and 

 alfo in common air faturated with nitrous air, bu£ 

 efpecially in the former. 



Neither nitrous air, nor common air faturated 

 with nitrous air, differs in fpecific gravity from 

 common air, or, at leaft, fo little, that I could 



Vol.. LXIL F f not 



