126 TRANSACTIONS OF THE [MAY 23, 
Pror. Oapen N. Roop, of Columbia College, delivered the last 
lecture of the Public Course on ‘‘ Color,” illustrated. At the close 
of the discourse a vote of thanks was extended to Pror. Roop, and 
the meeting adjourned. 
May 23d, 1892. 
STATED MEETING. 
The President, Dr. Hupparp, in the chair. Seventeen persons 
present. 
The minutes of May 16th were read and approved. 
The following papers were then read :— 
Sucrose, Dextrose, and Levulose; their Quantitative De- 
termination when Occurring Together. 
BY DR. F. G. WIECHMANN. 
Commercial Oil-testing. 
BY DR. H. T. VULTE. 
Petrographical Notes. 
BY JAMES F. KEMP. 
i 
A Remarkable Erratic from Aurora, Cayuga Co., N.Y. Nearly 
a year ago, Professor J. W. Freley, of Wells College, Aurora, 
called the writer’s attention to a remarkable rock that had been 
found by him as a boulder two feet or so in diameter, ‘‘in the bed 
of a small ravine only a few rods south of Wells College.” Its 
angles are described as being quite well rounded. A moment’s ex- 
amination of a hand-specimen showed that it was something un- 
usual, and more careful study of a larger supply which Professor 
Freley kindly supplied, has corroborated the impression. The rock 
belongs with the hitherto seldom described basic rocks, which lack 
feldspar entirely, have a glassy base, and have been called monehi- 
quite’ when possessing much olivine, and fourchite’ when lacking 
1M. Hunter and H. Rosenbusch, Ueber Monchiquit, ete. Tsch. Min. u. 
Petrog. Mitth., xi, 1891, p. 445. 
2 J, F. Williams, Igneous Rocks of Arkansas. Ann. Rep. State Geol., 1890, 
vol. il. 
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