•English Patents granted from 1675 to 1829. 43 



in order, which may easily be done, by having a water-tight 

 case for that small part of the instrument. Experience will 

 show how far the theoretical principles above laid down are 

 rigorously accurate in practice. The Newtonian result for R 

 has required some modification to coincide with the experimen- 

 tal results derived from projectiles; but it is probable, that 

 where the velocities and spaces are so small as in all cases of 

 the anemometer, it will be found almost mathematically accu- 

 rate. But, whatever may be the amount of these errors, it is 

 of little consequence in the general principle, as any small em- 

 pirical coefficient may be employed, which, from accurate ex- 

 periments in a few particular velocities, may appear requisite. 



CoLiNTON House, October 26, 1829. 



Art. V. — List of the Number of Patents granted for In- 

 ventions in England, from the year 1675 to 18295 inclusive ; 

 also a List of Patents in force 1815-1829. ^ 



A Select Committee of the House of Commons was appointed 



lead ; and, considering their great regularity of surface and perfect equali- 

 ty of size, 1 am disposed to think that the small quantity of the deflection 

 might be overlooked ; for when the velocities are considerable, the deflec- 

 tions found for former cases are in fact too large for convenience, and it 

 probably would not be advisable to reduce the space of exposure below three 

 or four feet. Let us see, therefore, what would be the amount of deflec- 

 tion in the first example given above, the density of the shot being as 

 11.37 to 1, and the diameter as i to 1, or being 1-lOth inch. V =^ 40. 

 2 a log. 1.57209 

 5.68 0.75435 



Deflection, 0.899 ft. or about 11 inches. 



