VI. Abstract of experiments made to determine the 



TRCE RESISTANCE of the AIR to the SURFACES 

 o/'bodies, of various figures , and moved through it •with 

 different degrees of velocity. By C HA RLE s ffurroN, LL.!). 

 Frofe[fur of Mathematics in the Royal Military Academy, 

 Woolwich, and F. R. S. LoND. & Edin. 



{Read by Mr RoBISON, Jan. i. 1787.] 



I. T^HE experiments from which the following are extradl- 

 A ed, make part of a courfe, inftituted at the Royal Mili- 

 tary Academy, for determining the refiflance of the air to a fur- 

 face of any form whatever, either plane or curved, moved 

 through it with any degree of velocity. I was induced to un- 

 dertake thefe experiments, both for the improvement of my 

 Undents in the Academy, and with a view to apply the conclu- 

 fions derived from them towards perfedling the theory and 

 pradtice of military projedliles, as well as other branches of na- 

 tural philofophy, in which the preffure or reliftance of fluids 

 is concerned : Circumftances, concerning the laws of which, 

 authors on the theory have widely differed ; fome making the 

 preflure or refiftance equal to the weight of a column, whofe 

 altitude is equal to the whole height due to the velocity, while 

 others make the altitude very different, either the half or the 

 double of that. This altitude, however, it is evident, will be va- 

 rious, according to the nature of the fluid, whether elaftic or 

 non-elaftic, ^c. or according to its difierent degrees of com- 

 preffion. I have, therefore, confined thefe experiments to the 

 preflure and refiftance of the air only, being that which afFeds 



the 



