NEWTON S PRINCIPIA. 387 



the pressures become the same in the two vessels which 

 the orifice puts in communication. These are the results 

 of MM. Venant and &quot;Wantzel ; they have even deduced 

 an empirical law to represent the velocity. The efflux 

 per metre of orifice in volume at pressure P will be 



m 



n 



where m, n are two numbers which depend on the nature 

 of the orifice, and M a number to which we give a value 

 a little greater than n, that the formula may give a nearly 

 constant value to V between the limits already stated. 



c c 2 



