Record. lxv 



the density of air in C. G. S. units at the temperature and 

 pressure of the observations. He finds the pressure a max- 

 imum when the axis of the collector is parallel to the direc- 

 tion of motion with the mouth to the wind. Turning the 

 collector until its axis makes an angle of about 60° with this 

 position, the pressure reduces to zero. At greater angles the 

 pressure becomes less than atmospheric pressure by an amount 

 which reaches a maximum at an angle of 90°, and passes 

 through a minimum at an angle of 180°, when the collector is 

 in a trailing position. The sum of the coefficients for the two 

 positions of maximum and minimum exhaust is almost exactly 

 the same as Langley obtained with a pressure board when ex- 

 posed normally to the wind. The result shows that a large 

 amount of air is dragged along with the train, the motion 

 being communicated to air many feet away. This air is a 

 source of danger to one standing too near the train when it is 

 at full speed. One is likely to be toppled over, and the blow 

 of the air communicates a motion of rotation which may cause 

 one to roll under the train if the nature of the ground does 

 not prevent such result. It was remarked, however, that 

 where trains have a right to run at any speed, no prudent 

 person would stand so near a train as is necessary in order to 

 be in danger from this source. 



Mr. Alfred Clifford, of St. Louis, was elected an active 

 member. 



Two persons were proposed for active membership. 



January 18, 1897. 



Vice-President Sanger in the chair, a large number of mem- 

 bers and guests present. 



Professor H. S. Pritchett presented some results of obser- 

 vations on the recent sun-spots, prefacing his remarks by a 

 general account of our present knowledge of the constitution 

 of the surface of the sun, and of sun-spots in general, and 

 illustrating them by the use of lantern slides. 



The following persons, resident in St. Louis, were elected 

 active members : — H. A. Hunicke, Julius C. Strauss. 



