APPLICABLE TO MATHEMATICS, &C. 345 



water, together with the friction of the water on 

 the sides of the vessel. In the second place, the 

 data required is to obtain the limits of disturbance 

 of the fluid mass, which I shall call the solid of 

 distwhance. This is an essential and important 

 element in the investigation of fluid motion, in 

 consequence of its connexion with the theory of 

 the transmission of sound. The time should be 

 carefully obtained in which the initial disturbance 

 of the fluid reaches the confines of the solid of 

 disturbance. The law connecting these elements 

 with the pressure which produces the fluid motion, 

 and also the law which regulates the transmission 

 of the pressure, can only be obtained by a nu- 

 merous and Vt-ell-conducted set of experiments. 



There is another important datum which is 

 closely connected with the naval architecture of 

 this country — it is this : when the canvass is 

 employed to collect the force of the wind, the 

 point where the resultant will pass through, for 

 currents of varying intensity, should be well 

 ascertained. These I conceive to be amongst 

 the most important parts of the data which are 

 required to apply mathematics to the science of 

 Hydrodynamics. 



Yy 



