ELISHA MITCHELL SCIENTIFIC SOCIETY. 53 



As long as the components N X and S Y are equal, the rotating 

 mass of air is driven forwards in the Hne A B and is constantly acted 

 on by these forces S, S, &c., and N, N, &:c., which may be similarly 

 resolved, the components in direction of A B will be forces continu- 

 ously acting, aec' lerating the velocities of rotation and translation. 

 The maximum of each motion is reached when the accelerating force 

 is equal to the resistance to motion by friction, &;c. 



The actio necessarily begins along the southern edge of the 

 cloud, and -the whirl may reach the surface of the earth both by 

 friction against the air underneath and by the winds producing it 

 extending down to the earth. 



The tornado cloud is formed by the cooling of the air in the centre 

 of the rotating mass, which is the result of diminished pressure, 

 owing to the so-called centrifugal force. 



The upward rush of air along the axis of rotation is also due to 

 diminished pressure along that line. 



Electric phenomena would seem to be results and not agents. 



The greater extent of destruction on the south side of centre of 

 tornado track is also accounted for, since the supposition requires 

 that the wind on south side shall have a greater velocity than that 

 on north side and is able to prostrate trees, &c., before it begins to 

 w^hirl. 



University N C, May 3d, 1884, 



SOLUBILITY OF NORTH CAROLINA PHOS- 

 PHATE ROCK. 



J. L. BORDEN. 



In the American Chemical Journal (v. 6, p. 3), Gladding rei ords 

 certain experiments on the amounts of various natural phosphates 

 dissolved by ammonium citrate solution under different conditions. 

 With a view to comparing the newly found North Carolina phos- 

 phates with these a corresponding series of experiments were carried 

 out with some specimens in the possession of the University. The 

 conditions of the experiments were the same as is in the paper men- 

 tioned above. One gram of phosphate was used and ammonium 



