1881. ] Microscopy. 1029 
award. Persons intending to become members of the Society at 
the coming meeting can compete on the same terms as present 
members. Circulars giving particulars as to the required method 
of competition can be obtained from the Secretary, Professor 
D. S. Kellicott, Buffalo, N. Y. 
VERIFICATION OF OBJECTIVES.—The editor of the orthern 
Microscopist (Manchester, England), announces the opening of a 
verification department, in which it is proposed to publish, for a 
fee of eighteen pence to cover expenses, information in regard to 
any objective sent for examination. The following measurements 
will be given :—focal length and angular aperture as estimated by 
maker; linear amplifying power, working focal distance, and 
absolute size of field, at ten inches from front lens of objective to 
plane surface of eye-lens of ocular (which is a Ross A, with 
diaphragm aperture of 0.75 inch, and approximate magnifying 
power of 5 diameters); numerical aperture by Professor Abbe’s 
apertometer, and calculated equivalent air angle. Though not 
likely to work without some friction, this department will, if per- 
manently successful, be a great convenience to those owners or 
intended purchasers of lenses, who have not the experience or 
apparatus requisite to test them for themselves. It would be still 
more satisfactory, and would probably conduce to the increased 
success of such as might adopt the plan, if makers and dealers 
would have their lenses similarly examined and certified to by 
competent and impartial authority, before offering them for sale. 
MovuntTinG on SQuareE Surps.—Mr. J. Fenner proposes, in the 
English Mechanic, to mount microscope objects on glass one or 
Square instead of the standard 3x1 slips. These are to be pla 
in shallow circular paper boxes, just large enough to ate 
them, which may be obtained cheaply i in large quantities at the 
wholesale drug stores. The slide is to be covered with a card- 
board diaphragm snugly fitted into the box, perforated by a 
central opening through which to view the object, and covered 
with a gummed label. The bottom of the box has a central 
opening (previously punched through it) for the transmission of 
light ; and the cover is labeled and numbered to correspond with 
the box and with the owner’s register-book. As none of the 
the stage in any position, and rotated by the hand. They are 
evidently not suitable for delicate work or for use with high 
powers. 
Sehescignobic TEsT FOR Porson. ate: test fluids for such minute 
. of certain alkaloids as —_— not answer to a 
