Tur Microscopr. 43 
Second. What is the formula of a two-inch eye-piece as 
used in the microscope, not in the telescope ? 
Third. Whatis the magnifying power of a two inch eye- 
piece ten inches between the object and diaphragm ? 
Fourth. Are there fifty microscopes in this country fur- 
nished with two inch eye-pieces ? 
Fifth. What is the length of a ten-inch tube? 
Mr. E. Gundlach answers the first, 7.9 diameters. The third 
he answers, “ just six diameters,” and also says that the magni- 
fying power of an eye-piece is not varying with the distance of 
the object. To the fifth he facetiously answers, “ten inches I 
should think.” This last reply reminds us of a question we 
heard asked at a depot recently, “ what time is the four o’clock 
train due?” Or another, “what is the price of your ten cent 
sugar?” 
Repuration.—It is not a very difficult thing to acquire 
notoriety in almost any line of work. For proof of this one has 
only to read a single article of Dr. Rollin Gregg’s of Buffalo ; 
but additional proof comes from the pen of a “ microscopist”’ 
who writes to the Medical Bulletin that “ the best test of a fine 
section is the ease with which it floats in a glass of water. Those’ 
sections which sink are too thick for mounting, as arule.” He 
evidently never heard of such a thing as “specific gravity; ” 
perhaps he never performed that wonderful feat of our boyhood 
and made a needle float on water! Yet it occurs to us that a 
needle is rather too thick for mounting; as also acork, or a piece 
of lung tissue. In a word this “‘ best test ” is Just no test at all, 
as everybody knows, or ought to know, who has worked three 
weeks in practical histology. 
Dr. A. Y. Moore sends us another slide. It is not a slide of 
double-stained blood corpuscles; nor a microscopic Geissler 
tube; nor silver plated diatoms; but a slide of gold-plated 
diatoms, the isthmia nervosa. 
WE may soon expect to see other numbers of the Journal 
of the New York Microscopical Society. N. L. Britton, Ph. D., 
of the Columbia School of Mines, will be the editor. 
