1896. ] NEW YORK ACADEMY OF SCIENCES. 97 
REGULAR Business MEETING. 
January 1, 1896. 
In the absence of the President, the meeting was called to 
order by Prof. Woopwarp. There were twenty-six members 
and guests present. 
The minutes were read and approved. 
Dr. Franz Boas, of the American Museum of Natural HLis- 
tory, was nominated as resident member. 
Prof. M. I. Pupin then read before the Section of Astrono- 
my and Physics a paper on the ‘“ Magnetic Circuit.” In 
transformers, especially of closed iron core, it has long been 
known that the upper ‘‘ harmonics ” of the fundamental rate of 
alternators, present in the primary are choked out by the trans- 
former leaving the potential difference of the secondary coil 
represented by a simple sine curve. The choking out is less if 
the magnetic circuit is incomplete and least where the coils have 
no magnetic core. Various explanations have been offered to 
account for this phenomenon; and it is doubtless true that it is 
due to Foucault currents and to hysteresis. Dr. Pupin pointed 
out from certain mathematical considerations that by appropri- 
ate measurements, especially of the angle of lag, it would be 
possible to separate the energy consumed in Foucault currents 
from that consumed by hysteresis, and thus be able to study 
this latter puzzling phenomenon. Investigations are in progress 
to test the method experimentally. Prof. Crocker remarked 
upon the interest and importance of the questions involved. 
The second paper was by Dr. A. A. Julien upon “ The Con- 
densed Gas Film on the surface of Solid Bodies with relation to 
(1) Newton’s rings of the first order; (2) Sand flotation; (3) 
Sand in harmonic vibration. Owing to the lateness of the hour, 
Dr. Julien passed over the first two heads, giving an outline of 
the literature of the question of liquid films on solids. He then 
outlined his experiments in sonorizing sands artificially and in 
demonstrating the necessity of an antecedent water film before 
TRANSACTIONS N.Y. ACAD. SCI., Vol. XV., Sig. 7, April 9, 1896. 
