L7aNSOING Ve Ate Sr. 100 j May 12, 
Mrs. A. C. Kercuam and Dr. R. H. Lamporn were elected 
Resident Members. 
A paper was then read by Dr. Louts H. Laupy, illustrated with 
apparatus, experiments, and lantern-views, entitled 
PHOTOGRAPHY—PAST AND PRESENT. 
May 12, 1884. 
SECTION OF GEOLOGY. 
The President, Dr. J. S. NEWBERRY, in the Chair. 
Thirty-seven persons were present. 
The PRESIDENT exhibited specimens of vanadite, descloizite, and 
a large suite of polished colored marbles from Vermont. 
Mr. G. F. Kunz exhibited specimens of a remarkable chloro- 
phane from Amelia County, Va., phosphorescent by friction, the 
heat of the hand, etc. 
The PRESIDENT, in discussing the subject of phosphorescence, 
referred to the specimens of luminous limestone from Utah, which 
he had exhibited at a former meeting. It had been reported that 
the blows of the pick upon this substance had kept the tunnel 
continually illuminated. This phenomenon, being a novel one to 
the miners, had caused them great alarm lest the mine might be 
getting on fire. 
A paper, illustrated with a suite of specimens, was then read by 
Mr. ARTHUR H. ELLIOTT, on 
THE COLORED MARBLES OF LAKE CHAMPLAIN. 
DISCUSSION. 
In reply to inquiries, the author stated that he had found no sul- 
phides in these marbles. In regard to their durability as building 
stones, he had observed that their weathered surfaces looked remark- 
ably hard and apparently very fresh. In Burlington, a few buildings 
had been erected from the Willard’s Ledge stone and seemed to pre- 
sent good evidence of its durability. At the Swanton quarries all the 
surfaces had been freshly uncovered, and the weathered edges ap- 
peared sharp. In Swantona church had been erected some years ago, 
and the stone was well preserved. Fossils have been observed in the 
black marble. 
