1880. ] Microscopy. 693 
and the siphon slide, also designed by Mr. Holman. The edge of 
the cover or cap is beveled, so that by rotating it against the 
inflow and outflow tubes of the siphon arrangement, a very con- 
venient and effective compressor is obtained. The apparatus is 
equally as valuable as the compressor before described, because of 
the certainty with which one can gauge the amount of pressure 
which is applied; also on account of the facility with which 
water may be renewed in it when used as a “ moist chamber ” for 
studying growing fungi, without in the slightest degree disturbing 
these delicate plants. The value of the apparatus is further 
enhanced by the facility with which it may be used as a siphon 
slide for keeping aquatic larve, worms, etc., alive for a lengthened 
period for study or exhibition. It is equally useful as a dry com- 
pressor for holding, studying and drawing minute soft-bodied in- 
sects in the living state. These useful pieces of apparatus should 
be found upon the table of every working microscopist, where 
every day’s use will demonstrate their indispensibility. It was in 
one of Mr. Holman’s siphon slides, right under the microscope, 
that the writer successfully hatched young shad, a feat never be- 
fore performed with the eggs of fishes.— Fon A. Ryder. 
MeEruops oF Dry Mounrinc.—Slides made of wood are lighter 
and stronger than glass ones, and look quite as elegant if made 
of ornamental wood and polished, or covered with fancy papers. 
In the first place procure some thin boards, about one-sixth or 
one-eighth part of an inch thick; these should be cut up into 
