OF ARTS AND SCIENCES. 



323 



Fi?. 15. 



Time in Velocity per 

 Seconds. Second. 





27.6 



Feet. 



1.92 



Fig. 16. 



" Exp. 44. Elbow with its 

 mouth towards the blast, and 

 covered by a flat plate, 3 inches 

 in diameter and 1 inch from the 

 mouth, ..... 



" Exp. 45. Same elbow and 



plate, but turned in the opposite 



direction with reference to the 



blast ; current passed dovsrn the 



pipe, and traversed it in . 



"Same elbow, with a curved plate 1.75 inches in 



diameter, .75 inch from the mouth of the elbow ; 



mouth turned towards the blast, .... 



" Exp. 46. Conical tube, 4 inches long ; a plate 3 

 inches in diameter, and .75 inch distant from lesser 

 extremity, plate turned towards the blast, 



" The experiments which follow are on the influence of ventilators 

 upon a current already established, and moving with a certain velocity 

 in the same direction with that produced by the ventilator. The cur- 

 rent is established by placing the farther end of the leaden pipe — that 

 which has heretofore been kept carefully beyond the influence of the 

 blast — in the blast, in such a manner that it shall receive more or 

 less of its force. 



49.0 1.08 



36.0 1.45 



38.0 1.40 



Velocity of established current in seconds, 

 " " " feet, 



Elbow with plate ; plate towards the blast, . 



Cone, fig. 9, without its plate, 



Same, with its plate, 



Saint-Martin's cone, ....*... 



Saint-Martin's cone and cap, 



Cone ; angle of sides 7P ; height 1 5 inches, 

 Conical tube, Exp. 31, lesser end to the blast. 

 Conical tube of 47^, lesser end to the blast. 

 Conical tube, Exp. 30, lesser end to the blast, 

 Conical cap ; tube of 47°, lesser end closed and 



turned to the blast, 



Conical tube ; length 2 inches ; diameter at 

 smaller end 1.25; at larger, 2 inches, over 

 which and 1 inch from it is a plate 2.5 inches 

 in diameter, turned to the blast ; smaller end 



in the leaden pipe, 



Elbow ; plate 175 inches in diameter : .5 inch 



from mouth of elbow ; plate towards the blast. 



Same, with plate .75 inch from mouth of elbow, 



Same ; plate 2.5 inches in diameter, 1 inch 



from elbow 



29 

 1.83 



» 

 197 



26 5 



26.5 



25.0 



26.2 



ft. 



2 69 

 2.00 

 2.00 

 212 

 2-02 



15.5 

 3.42 



II 

 14 5 



17.2 



14.5 



14.2 

 15.0 

 14.5 



ft. 

 3.66 

 3.08 



3.66 



3 72 

 3 53 

 3.66 



26.5 

 2.00 



18':3 



ft. 

 2.89 



26.0 



217 



165 

 18.2 



17.0 



20.5 



20.0 



2.04 



2.46 

 3.21 

 2.90 



3.11 



2.58 



2.65 



20.75 2.55 

 17,6 13.00 



