PROCEEDINGS OF SOCIETIES. 173 
be made, for it is furnished with boxwood scales corresponding to 
the magnifying powers of the different objectives employed. Thus, 
the image may be treated as a drawing, and measured and 
delineated with rules and compasses in the usual way. All the 
necessary adjustments can be effected from the inside, in order to 
avoid the inconvenience to the observer of continually altering 
bis position. The use of this microscope is not entirely confined 
to the examination of transparent objects, for an image of many 
of the opaque bodies may be shown with it on the paper. The 
effects of dark field illumination (with the paraboloid and Lieber- 
kuhn) and those of the polariscope may be shown on the paper 
without loss of definition, and all these accessories, as well as the 
objectives used, are the same as those of a microscope of the 
ordinary construction. The whole apparatus is made to fold up so 
as to occupy as little space as possible for the sake of portability. 
Mr. Cooke also exhibited a simple form of heliostat, which is 
useful when the camera is worked for a long time with sun-light. 
Mr. Ross, relying on his well-earned fame rather than on question- 
able novelties, exhibited, in a collection of his highly-finished first- 
class instruments, a variety of specimens of marine Polyzoa, &c., 
remarkable for their beauty and the perfection with which they 
were shown.—Messrs. Powell and Lealand showed their new 
binocular with some first-class instruments. Under one of their 
instruments was exhibited a beautiful illustration of the marvellous 
power of the eye of a beetle. A likeness of the Princess of Wales 
was reflected through the 100 facets of taat compound structure, 
and in each part was distinctly seen a perfect image of the 
Princess. Mr. Lealand also showed the objects for which he is so 
celebrated, the circulation in the Vallisneria and the Volvox 
globator.— Messrs. Smith and Beck exhibited a variety of beautiful 
objects under many of their best instruments.—Mr. James How 
had some beautiful examples of Zoophytes with expanded tentacles, 
Halodactylus, Sertularia, &c.; the larve of the shore crab, circu- 
lation of the blood in the frog, specimens of Trichina spiralis in 
human muscle, &e. Mr. How also exhibited, in one of the rooms 
upstairs, by means of the oxyhydrogen light, a selection of photo- 
micrographs by Dr. Maddox, consisting of vegetable structures, 
diatoms, parasites, parts of insects (some of these exibited for the 
first time), such as preparations of the head and wings of the male 
and female gnat,and larve and pupa state of the same, and a fine 
photograph of the tongue of the house-cricket.—Mr. Baker 
showed binocular microscopes, under which were many striking 
illustrations of pond and marine life—such as Tabularia and 
Campanularia, minute crabs, and other crustaceans, fresh from 
their native element, a novel feature in objects usually shown at 
these meetings.—Mr. Charles Tyler exhibited silicious sponges 
from Barbadoes, opaque and in section; new Grantias from 
Australia ; keratose sponges, with a new variety from Australia ; 
a unique sponge with inhalent orifices. Dr. Miller showed 
Conochilus Volvox in his usual beautiful manner, and recent 
VOL. VII.—NEW SER. . N 
