speak of the wonderful
stereoscopic figures of the moon taken by Mr. De la Rue in England, by Mr.
Rutherford and by Mr. Whipple in this country. To these most successful
experiments must be added that of Dr. Henry Draper, who has constructed a
reflecting telescope, with the largest silver reflector in the world,
except that of the Imperial Observatory at Paris, for the special purpose
of celestial photography. The reflectors made by Dr. Draper "will show
Debilissima quadruple, and easily bring out the companion of Sirius or the
sixth star in the trapezium of Orion." In taking photographs from these
mirrors, a movement of the sensitive plate of only one-hundredth of an
inch will render the image perceptibly less sharp. It was this accuracy of
convergence of the light which led Dr. Draper to prefer the mirror to the
achromatic lens. He has taken almost all the daily phases of the moon,
from the sixth to the twenty-seventh day, using mostly some of Mr.
Anthony's quick collodion, and has repeatedly obtained the full moon by
means of it in _one-third of a second_.

In the last "Annual of Scientific Discovery" are interesting notices of
photographs of the sun, showing the spots on his disk, of Jupiter with his
belts, and Saturn with his ring.

While the astronomer has been reducing the heavenly bodies to the
dimensions of his stereoscopic slide, the anatomist has been lifting the
invisible by the aid of his microscope into palpable dimensions, to remain
permanently recorded in the handwriting of the sun himself. Eighteen years
ago, M. Donne published in Paris a series of plates executed after figures
obtained by the process of Daguerre. These, which we have long employed in
teaching, give some pretty good views of various organic elements, but do
not attempt to reproduce any of the tissues. Professor O.N. Rood, of Troy,
has sent us some most interesting photographs, showing the markings of
infusoria enormously magnified and perfectly defined. In a stereograph
sent us by the same gentleman the epithelium scales from mucous membrane
are shown floating or half-submerged in fluid,--a very curious effect,
requiring the double image to produce it. Of all the microphotographs we
have seen, those made by Dr. John Dean, of Boston, from his own sections
of the spinal cord, are the most remarkable for the light they throw on
the minute structure of the body. The sections made by Dr. Dean are in
themselves very beautiful specimens, and