[223 3 



trous air, which had been itfelf diminished one half 

 by warning in water. The fmell of them both was 

 alfo the fame ; fo that I concluded it to be the fame 

 thing, that part of the nitrous air which is im- 

 bibed by water being retained in this folution. 



In order to difcover whether this was the cafe, I 

 made the folution boil in a fand heat. Some air 

 came Jrom.it in this flare, which feemed to be the 

 lame thing, as nitrous air diminished about one lixth, 

 ©r one eighth, by warning in water. When the 

 fluid part was evaporated r there remained a brown 

 fixed fubftance, which was obferved by Mr. Hel- 

 lot, who defcribes it, Ac Par. 1735, M. p. 35.. 

 A part of this I threw into a fmall red hot cruci- 

 ble ; and covering it immediately with a receiver,. 

 Handing in water, I obferved that very denfe red 

 fumes rofe from it, and filled the receiver. This 

 rednefs continued about as Ions: as that which is - 

 occafioned by a mixture of nitrous and common 

 air; the air was alfo considerably diminimed within 

 the receiver. This fubftance, therefore, muft cer- 

 tainly have contained within it the very fame 

 thing,, or principle, on which the peculiar pro- 

 perties of nitrous air depend. It is remarkable, 

 however, that though the air within. the receiver 

 was diminifhed about one fifth by this procefs, it 

 was itfelf as much affected with a mixture of ni- 

 trous air, as common air is* anda candle burnt in* 

 it very well. This may perhaps be attributed to 

 fome efFec~t of the fpirit of nitre, in the compofition^ 

 of that brown fubftance. 



Nitrous air, I find, will be considerably dimi- 

 nifhed in its bulk by (landing a long time in wa- 



rer^ . 



