MRASUUlNG OF AIR. 431 



Hence expanding- (1 -j- .v)" where 



n-l U 



+ 



1.2 p, 

 The square root of the product of these terms is 



Multiplying by P^ \/ ~ . ~ 



tC 1 \ K i 



3n— 1 

 and find the formula for calculating the weight of air passing 

 through the orifice to be : 



This formula has been derived by Mr. G. AI. Clark of the 

 Victoria Falls and Transvaal Power Coy. and the author for 

 the purposes of the test at the 215 Drill Turbo-Compressor, 

 referred to later on. This test has also been made jointly by 

 Mr. G. M. Clark and the avithor, whilst the test of the 75 brill 

 reciprocating compressor, also referred to later, has been made 

 jointly by Mr. H. Collens of the Victoria Falls and Transvaal 

 Power Coy., and the author. 



Bv the use of this formula in the last form the numerical 



calculations become (|uite simple. The final term , 1 ~f" 4 f 



. 'pj> 



5n~ 1 



K 



as well as the correction term for adiabatic exjjansion //'A 



in the term introducing the velocity of approach may be fre- 

 quently neglected, ^^^^en using this simplified formula, it should 



