THE MOTION OF STEAM VESSELS. 



311 



The following experiments on His Majesty's steam- vessel Dee will illustrate the 

 formula : 



Power, 200 horses. 23 strokes per minute. 



, , ^ r Time of running a mile against the tide 



I with the tide . 



, p, r Time of running a mile with the tide 



1 against the tide 



, -p, r Time of running a mile with the tide 



I = against the tide 



5 51 or 351 



5 33 or 333 

 4 23 or 263 

 7 58 or 478 

 4 50 or 290 



6 35 or 395 



„ / 351 +333 1 „ M , 



1st Exp. V = { ^ g^^ — ggg >3600 = 10*52 miles per hour. 



(26*3+478 ") 

 ^-ggg-^j 3600 = 10-58 



272907395 j ^^^^ = ^^'^^ 



Mean = 10-62 



In this way the actual speeds of the vessels in the annexed Table have been deter- 

 mined. 



The remaining columns, not being calculated results, will be sufficiently under- 

 stood by the heads. 



2 s 2 



