322 PROCEEDINGS OF THE AMERICAN ACADEMY 



Time in Velocity per 

 Seconds. Second. 



" Exp. 35. Revolving conical ventilator, accord- peet. 



ing to the proportions of the inventor, . . .41.0 1.29 



" In the following experiments on the velocity of currents through 

 the same length of leaden pipe, the current was produced by the same 

 blast acting upon mouth-pieces of different forms and dimensions, ap- 

 plied to the leaden tube and presented fairly to the blast. 



pj„ j^ " Exp. 36. Elbow, opening turned 



towards the blast ; current traversed 

 leaden pipe in ... . 19.0 2.706 



" Exp. 37. Conical tube, Exp. 30, 

 closed at lesser end, the other turned 

 to the blast, 19.7 2.69 



'■'■ Exp. 38. Conical tube, Exp. 31, closed at less- 

 er end, the other turned to the blast, . . . 1S.6 2.85 



" Exp. 39. Conical tube, Exp. 33, closed at lesser 

 end, the other turned towards the blast, . . . 16.0 3.31 



" Exp. 40. Conical tube, 2 inches long ; diame- 

 ter of larger extremity 1.25 inches ; diameter gf less- 

 er .8 inch, which is presented to the blast, . . 19.7 2.69 



" Exp. 41. A glass tube, .25 inch bore, and long 

 enough to reach from the centre of the trunk beyond 

 its side, and, consequently, beyond the influence of 

 the blast, was fastened by one of its extremities in a 

 small hole bored for this purpose in the side of the 

 conical tube used in the last experiment, and near its 

 larger extremity. The conical tube was placed in the 

 same position as before. On presenting the flame of a 

 candle or any light substance near the open extremity 

 of the glass tube, a current of air was perceived flow- 

 ing into the tube. 



" Exp. 42. Saint-Martin's cone and cap (see fig. 6), 

 with its axis parallel with the blast ; blast directly 

 upon the top of the cap, ..... 29.0 1.83 



" Exp. 43. Cone of 45°, with flat plate (fig. 9), 

 axis parallel with the blast, as in preceding experiment, 29.5 1.80 



