156 TRANSACTIONS OF THE [APR. 8, 
(5) Polariscopes (not used). 
(6) Photometers. 
Several results were secured by the Amateur Photographers’ 
Association. Mr. Leuschner made 7 measures of the total light 
of the corona with a. modified form of wheel- or disc-photo- 
meter. The Harvard party used a quadruplex photographic 
telescope, with perforated tin plates having several hundred 
apertures, and a measure can be made of the intensity of the 
coronal light which has passed through each aperture. Twenty- 
five negatives were obtained on dry plates which had been 
accurately standardized by Mr. Pickering at the Harvard 
Observatory. 
April 8, 1889. 
STATED MEETING. 
The President, Dr. NEWBERRY, in the chair. 
Sixty-four persons present. 
The meeting was held in the Geological Lecture-room of the 
School of Mines building, for convenience in displaying and 
examining the specimens described in the first communication. 
Dr. NEWBERRY then gave the paper of the evening, upon 
AMBER: ITS HISTORY, OCCURRENCE, AND USE. 
(Abstract. ) 
He began by referring to a very large and rich collection of 
specimens of amber, illustrating all the varieties found in the 
amber district of North Germany, which had recently been sent 
to the School of Mines as a present by one of its earliest gradu- 
ates, Mr. H. A. DEMELLI, forsome years pasta resident of Berlin. 
This gentleman had enjoyed unusual opportunities for obtaining 
rare and choice specimens of amber, and had made this re- 
markable collection as an expression of interest in the institution 
where he had studied in former years, and sent it over in a very 
elegant case of inlaid work, etc.—itself a beautiful work of art. 
[The cabinet and its contents were exhibited to the members 
in the adjoining Museum-room. A great variety of rough am- 
bers, of all shades and qualities, were displayed on the upper 
shelves; and below, a remarkable collection of cut and polished 
specimens, containing insects and leaves. | 
