250 Analyfn of the Air. 



confequently the veficles will fall flat, not- 

 withstanding the endeavours of the extend- 

 ing Thorax to dilate them as ufual ; whereby 

 the motion of the blood thro' the lungs being 

 flopped, inftant death enfues. 



Which fudden and fatal effect of thefe 

 noxious vapours, has hitherto been fuppofed 

 to be wholly owing to the lofs and wafte of 

 the "chifying fpirit of air ; but may not 

 unreaibnably be alfo attributed to the lofs 

 of a conliderable part of the air's elafticity, 

 and the groffhefs and denfity of the vapours, 

 which the air is charged with ; for mutually 

 attaching particles, when floating in fo thin a 

 medium as the air, will readily coalefce into 

 groffer combinations : which effect of thefe 

 vapours having not been duly obferved be- 

 fore, it was concluded, that they did not 

 ^ffedt the air's elafticity ; and that confe- 

 quently the lungs muft needs be as much 

 dilated in infpiration by this, as by a clear 

 air. 



But that the lungs will not rife and dilate 

 as ufual, when they draw in fuch noxious 

 air, which decreafes faft in its elafticity, I 

 was affured by the Experiment I made on 

 myfelf, in Exper. 108. for when towards the 

 latter end of the minute, the fuffocating qua- 

 lity 



