316 



PKOCEEDINGS OF THE AMERICAN ACADEMY 



" Exp. 4. Elbow ; horizontal portion 4 inches long, 

 opening turned from the blast, .... 



" Exp. 5. Same ; horizontal portion making, with 

 the direction of the blast, an angle of 30°, 

 "Same; angle of direction 45°, 

 "Same; " " 60"^, 



"Same; " " 90°, 



Fig. 4. 





Fig. 5. 



" Exp, 6. Elbow turned from 

 the blast, and having around its 

 opening a plane surface 1.5 

 inches wide, . . . .31.0 



" Exp. 7. A perpendicular 

 plate 2 inches wide and 1.75 inch- 





(C 



(( 



31.5 



28.2 

 27.3 

 29.0 

 28.7 

 39.0 

 65.0 



1.71 



es in height, fastened to that side 

 of the fixed tube next the blast, . 33.0 1.61 

 " Same plate attached to the 

 fixed tube, but with its edges in the same direction 



with the blast, 48.0 1.05 



" Same plate on the side of the fixed tube, opposite 

 the blast, ..... no effect in 180.0 



" Exp. 8. A square plate, 2 inches by the side, on 



the top of the fixed tube on the side next the blast, . 



"Same plate making with horizon an angle of 80°, 



75°, 



70°, 



67°, 



45°, 



" " " 22° 



" Exp. 9. Square plate, 2 inches by the side, with 



vertical edges .5 inch wide, turned from the blast, and 



making an angle of 45° with its direction ; the whole 



plate making an angle of 75° with the horizon, 



" Same plate, making same angle with the horizon, 

 but with its edges turned in the opposite direction ; 

 that is, towards the blast, 



" Exp. 10. A plate 1.25 inches wide at the base, 2 



1.68 

 1.87 

 1.94 

 1.83 

 1.85 

 1.36 

 0.791 



31.0 1.71 



24.6 2.15 



