324 



PROCEEDINGS OF THE AMERICAN ACADEMY 



" The established current in the following experiments varied some- 

 what in the different experiments, but was constant during the same 

 experiment ; they cannot, therefore, be compared with each other 

 without reference to the velocity of the established current. 



Saint-Martin's cone and cap, 



Same cone without cap, 



Cone, fig. 9, witli its plate, 



Same cone without its plate, 



Model of a cliimney ; 2 inches by the side ; end flat and 



horizontal ; 4 inches long, 



Model of same dimensions; top bevelled; angle of sides 



with horizon 40°, 



Same ; angle of plane of top inclined towards the blast, 



at an angle of 15°, 



Same ; same inclination ; .75 inch above top a plate 2.5 



inch in diameter, 



Same, without the plate ; inclined towards the blast 20°, 



Same; inclined towards the blast 30°, 



Same, at same inclination ; plate .75 inch above the top, 

 Chimney model, with flat top inclined towards the blast, 



at the same angle, 30°, 



Model and inclination same ; plate 3 inches in diameter, 



.75 inch above the top, 



Conical revolving cap ; angle of sides 47°, apex towards 

 the blast, 



Conical cap, fig. 12, 



Similar cone, with opening at apex, 1.25 inches in diam- 

 eter, fig. 13, 



Conical revolving cap ; angle of sides 47°; apex to blast, 



Same, with opening at apex, 1.25 inches in diameter; 



apex to the blast, 



Established 

 Current. 



22"7 

 22.2 

 25.5 

 23.7 



26.0 



26.0 



26.0 

 26.0 



26.0 

 26.0 

 26.0 



260 

 26.0 



24.4 

 27 5 



27.5 

 27.2 



27.2 



ft. 

 2 33 

 2.39 

 2.08 

 2.27 



2.04 



2.04 



2 04 



2.04 

 2.04 

 2.04 

 2.04 



2.04 

 2.04 



217 

 1.92 



1.92 

 1.94 



Current in 

 Pipe. 



25.5 I 2.08 

 26.5 i 2.00 

 27.0 ; 1.96 

 27.0 1.96 



18.7 

 21.5 

 21.7 



2.83 

 2.47 

 2.44 



21 7 '244 

 22.6 2 34 

 29.6 1 79 

 25 6 2 07 



1.94 



52.5 

 42.0 



17.8 



1.00 

 1.26 



2.97 



18.5 2.86 



18.0 I 2.94 



21.2 250 



I 

 20 2 65 



" The current established in the pipe was raised in temperature 

 above that of the impinging current or blast, by placing the pipe in a 

 vessel of hot water. The current in the pipe assumed a temperature 

 of 104°, while that of the blast was 64°. 



" Elbow with a plate .87 inch from its mouth and turned a. ,, 



towards the blast ; temperature of current 64° ; velocity 2.08 25.5 

 " Same ; temperature of current 104°, . . . 2.08 25.5 



" Several other experiments were made, but the results coincided so 

 nearly that they may be considered as identical. 



" The proportions of those forms of ventilators which the Commit- 

 tee have found most efficient will be placed in the hands of manufac- 

 turers." 



