[ 389 I 



it has not been in my power to repeat them: if it had I' 

 would not take the liberty to offer them to the public fo im- 

 perfe(5l : they are prefented as hints to diredl the enquiries of 

 others, who are fo circumftanced as to be able to profecute, 

 them, and alfo as fuggefting perhaps the bcft teft of the; 

 pneumatic engine's exhau fling power. 



