250 
POPULAR SCIENCE REVIEW. 
remark, in connection with the subject of illumination of opaqne objects 
under high powers, that the principle upon which both Mr. Dancer’s and 
Mr. Smith’s appliances are constructed was described five years ago by 
Mr. Hewitt. 
Noberfs Test-plates. — In one of the late numbers of the new and excellent 
Microscopical Journal edited by Herr Max Schultze, this savant has a paper 
on Nobert’s test-plates. It appears that Nobert now prepares his tests in a 
new form. The specimens described by the writer contain nineteen groups 
of lines, from T - 0 W w to Tvforv'' apart, and thus arranged : — 
1st set, -j-oVxr* 3rd set, -5-0 Vu- 18th set, 
2nd „ t-sVc* 4th „ -i5 l oxr) & c * 19th ,, TTroTTir* 
The highest set M. Schultze has been able to define with central illumination 
is the 9th, which is resolved by Hartnack’s immersion system No. 10, and by 
Merz’s immersion system With oblique illumination he has not been 
able with any combination to get beyond the 15th. He considers the most 
difficult specimens of Pleurosigma angulatum to be about equal to the 8th or 
9th set of Nobert’s lines, and the larger instances to correspond with the 
7th. — Yide Quart. Journ. Microscop. Science, January. 
Specimens of Trichina. — We have received from Mr. Collins a very good 
specimen-slide, in which a number of Tric hin ae from the flesh of pork are 
well shown. With a power as low as two-thirds of an inch the worms come 
out very nicely. In some few cases the sacs are ruptured, and the little 
isolated parasite may be seen separately coiled up. 
A Pocket Compound Microscope, of very ingenious construction, has been 
devised by Mr. William Moginie, of Messrs. Baker’s establishment. When 
packed in its case the instrument appears as a small oblong box, which may 
be easily placed in a great-coat pocket. When required for use, the “ body,” 
containing an attach ed stage, is taken out and fastened on the cover, into the 
lower part of which a small mirror is inserted. A leg, moving upon a hinge. 
