78 TRANSACTIONS OF THE [FEB. 11, 
sometimes on the north side and sometimes on the south side. 
Spots were also indicated which showed, when near the limb of 
the sun, the penumbral region wanting on the side farthest from 
the centre and well developed on the side toward the centre. 
So far as indicated by these photographs, there was no doubt 
that the Wilson theory did not completely explain the various 
phenomena. 
Professor Rees also showed some pictures of sun-spots 
taken by Mr. C. A. Post, of New York City, exhibiting the 
non-central character of the umbra with respect to the penum- 
bra. Mr. C. A. Post, of New York City, then threw on the 
screen some original photographs of the sun and moon. He 
also exhibited a series of strikingly beautiful lantern slides 
made from photographs of lightning flashes by Mr. Bridgham, 
president of the New York Camera Club. 
The third paper was by M. I. Pupin “ On a new form of auto- 
matic mercury vacuum pump.” It consists of a sprengel pump 
of especial form combined with a very ingenious device for lift- 
ing the mercury to the reservoir again by means of an auxiliary 
pump of low capacity. At the close of the meeting the mem- 
bers and guests visited Professor Pupin’s laboratory and saw 
the pump in operation. The pump that was shown is a slight 
modification of the one described in the Am. Journ. Sci., 1895, 
Vol. 49, p. 19. 
Wo. HALLOCcK. 
Recording Secretary of Section. 
SrateD MEETING. 
February 11th, 1895. 
Biological Section, Professor Britton in the chair. 
_ An attendance of twenty-eight. - 
Previous to the organization of the Biological Section, the 
Recording Secretary presented a communication from the Sci- 
