XX vi Trans. Acad. Sci. of St. Louis. 



The death of Dr. Jacob Schneck of Mt. Carmel, III, was 

 announced. 



Dr. Wm. Trelease exhibited a copy of the interesting first 

 edition of Oviedo's ''Historia General de las Indias." 



January 21, 1907. 



President C. M. Woodward in the chair; attendance, twenty- 

 three. 



Dr. 0. H. Brown addressed the Academy on ''The Problems 

 of Tuberculosis." 



February 4, 1907. 



President Woodward in the chair; attendance, twenty-two. 



Prof. James F. Abbott and Dr. Louis Brandenburger were 

 elected to membership. 



Prof. F. E. Nipher spoke on the question, ''What is an Electric 

 Current?'' 



In this paper the difference between the flow of the electric 

 current and the flow of heat in a conductor was pointed out. 

 The flow of heat in a positive direction and the flow of cold in 

 the opposite direction are identical. This is not necessarily 

 true of a flow of positive electricity and of negative electricity 

 in opposite directions. Positive and negative currents will pro- 

 duce the same external electro-magnetic effects if they flow in 

 opposite directions, but the internal action is perhaps different. 



A positively charged body moved in a straight line produces 

 the effect of a positive current. A negatively charged body 

 moved in an opposite direction will produce the same electro- 

 magnetic effects. But we have here involved the motion of 

 masses of matter in opposite directions. The question to be 

 solved is, does this state of things exist in a conductor carrying 

 a current of electricity? 



Professor Nipher stated that he is planning a repetition of 

 Wheatstone's famous experiment with the rotating mirror. 

 The new conditions, which he has devised, may result in separat- 

 ing positive and negative currents, so that either may be sent 

 through a long wire having spark-gaps. An overhead line of 

 half a mile, with pole supports, will be required. The circuit 

 will be grounded on two flaming and insulated gas torches in 

 mid-air. The rotating mirror must be driven at a speed of 500 

 revolutions per second and must be made with great care. The 

 three sparks in the circuit are to be photographed, as shown in 



