116 THE AMERICAN MONTHLY [June, 
comes opposite the hole in the side, when the small amount of air contained in the 
latter will be found sufficient to enable a small drop to be taken upon a slide. This is 
probably the simplest and best method proposed. 
191, Roseville Avenue, Newark, N. J. FRANK VANDERPOEL. 
MICROSCOPICAL SOCIETIES. 
PITTSBURG, PENN. 
The Iron City Microscopical Society held a soireé on March 11th in the chapel of 
the First Presbyterian Church. The exhibition was very successful, there being in all 
fifty exhibits, each of which had three changes during the evening. A glance through 
the programme shows much the usual array of objects exhibited. Among them, of 
perhaps greatest interest, may be mentioned :—1. Section of human scalp, showing hair 
in situ. 2. Eggs of fish, showing embryo. 3. Section of foetal foot. 4. Cerebellum 
of man. 5. Human bone, transverse section. 6. Section of human tooth, showing 
nerve 7 sztu. 7. Head of Zenza solium, from dog. 8. Lung of steel-worker in health 
and disease. g. Living sugar mites. 10. Living cheese mites. 11. Living animal- 
cules from hay infusion. 12. Wing of humble bee, showing hooklets. The array of 
microscopes reported is very considerable, and must have been an interesting sight 
to one who is interested in comparing the various stands of various makers. The 
Society contains seventy members. 
—_O0—_— 
WASHINGTON, D. C. 
The 6oth regular meeting was given up to an exhibition of slides, principally a lot 
recently imported from M6ller by various members of the Society. Two type-plates, 
one of one hundred and one of four hundred diatoms, were shown, with other slides 
of different kinds. 
A noticeable feature was an ingenious adaptation of clock-work to a polariscope, by 
Prof. W. H. Seaman, by means of which the necessity of rotating by hand was 
done away with. 
One of J. Harbord Lewis’ desmid slides, containing some fifty species, was also 
shown. E. A. BALLocH, Rec. Secr. 
— 0— — 
SAN FRANCISCO, CAL. 
A regular meeting of the Society washeld upon April 13th. Upon the recommen- 
dation of the committee appointed to report on the matter, it was decided that the 
Chair should hereafter, at each meeting, appoint two members whose duty it would be 
to provide and display a number of interesting and attractive microscopic objects at 
the meeting next ensuing. 
As an instance of how a grain of truth may sometimes be transformed into a moun- 
tain of error, the Secretary read an item which has been going the rounds of the inte- 
rior press, and which announced the discovery of a new glass in Sweden, composed 
principally of boron and phosphorus, of such extraordinary refractive power that len- 
ses made of it would reveal the ‘one-two-hundred-and-four-million-seven-hundred- 
thousandth part of an inch!’ The basis of this extraordinary paragraph was pro- 
bably the recent introduction of the new optical glass made at Jena, containing small 
proportions of borates and phosphates. By the use of this glass it has been made 
possible to construct lenses with less chromatic aberration than heretofore, but as the 
refractive index is practically that of ordinary glass, the magnifyng power for any 
given curvature is, of course, also about the same. 
The exhibition of-the new ‘Doty Balsam-mounting Bottle’ brought out a discussion 
of various late methods in balsam mounting, and of the relative advantages of differ- 
ent mounting media. 
Dr. Mouser gave a brief description of the laboratory he has just fitted up for prose- 
cuting the study of the micro-organisms of disease. He concluded by extending a 
cordial invitation to the Society to examine the various appliances, and, on motion, 
the invitation was unanimously accepted, it being decided to hold the meeting of the 
27th inst. at the laboratory, 707 Bush Street. 
