AMERICAN JOURNAL OF SCIENCE. 
[THIRD SERIES] 
Art. XXXV.—On the use of Carbon bisulphide in prisms; 
being an account of Experiments made by the late Dr. HENRY 
DRAPER of New York.* 
d 
for the continuation and extension of this research were ander. 
taken in the new physical laboratory (which Dr. Draper had 
* The results which were obtained by Dr. Draper in his investigations on the 
cause of the difficulties encountered in the use of bisulphide in prisms 
Seemed so valuable and so likely to be of service to others eng: i 
page ; and have also made some supplementary measurements to test the 
efficiency of the ap 8, —GEORGE 
paratus, —GE F. Bak 
This Journal, IIT, xiv, 89, Aug. 1877; xviii 262, Oct. 1879. 
xxxix, 129, March, 1865, 
