NATURAL HISTORY MISCELLANY. 125 
the reef, more or less finely comminuted and not rich in animal 
life. In depths beyond the three hundred fathom line, but with 
considerable variation in its limits, we find again the Globigerina 
mud which also fills the greater part of the Gulf of Mexico in 
deep water. 
The Coast Survey intends to prosecute these researches next 
year with increased means. 
_ Foss WHALE IN THE Drirr.— The bones of a whale closely 
allied to the White Whale (Beluga leucas) of the Gulf of St. Law- 
rence, have been discovered at Cornwall, Ontario County, Canada. 
It seems to be the same as the B. Vermontana of Thompson.— 
Nature. 
MICROSCOPY. 
Puoto-MIcroGRAPHS FOR THE STEREOSCOPE. * — Before the sug- 
gestion in Carpenter’s last edition on the Microscope, that stereo- 
scopic pictures might be obtained by photographing a microscopic 
object alternately with the two sides of an objective, I had been 
working on the subject with some degree of success. Dr. Carpen- 
ter, however, seems to mention the fact rather as a means of 
convenient illustration, or a scientific curiosity, than as the expe- 
dient of great practical utility that I conceive it to be. 
Two or three methods seem to be applicable to the pr oduction 
of such pictures. Some objects, somewhat equal in width and 
depth, and visible under a lens of long focus, may be tilted by 
a simple, graduated, and carefully centred mechanical arrange- 
ment, first toward one side, and then equally toward the other, 
photographing each aspect by the same power and under essen- 
tially the same conditions: or, of certain objects under low and 
medium powers, a conception of solidity may be gained, by using 
photographs which are identical, except that, by a slight change of 
focus, they represent different planes of the object: or, the object 
and lens remaining unchanged, the lateral halves of the objective 
may be alternately stopped off, either directly, or by means of stops 
under the achromatic condenser, or by means of an achromatic 
condenser (of very small angular aperture) inclined first toward 
*From remarks by Dr. R. H. Ward, at ting of the Troy (N. Y.) Scientific Asso- 
ciation, Feb. 20th, 1871. 
