120 
THE YOUNG SCIENTIST. 
adapted to spread the web, and by means 
of small wooden pins, are fixed there. It 
is well to place a piece of very thin plate 
glass or thick covering glass under the foot, 
which must be kept thoroughly saturated 
with water. After considerable use of this 
frog-plate, we find it the most convenient 
we have ever used. It may be made of any 
suitable material; our first was made of an 
old cigar box, and then we had some made 
of brass, but we find that hard rubber is 
superior to anything else. 
A CoHecting Microscope. 
mniNKING that anything new in the 
way of microscopes may interest the 
readers of this journal. I send you a sec- 
tional cut (full size) of an immersion col- 
lecting microscope, recently made for me 
by the Spencers, of Geneva, N. Y. 
I have found it quite valuable when after 
desmids, diatoms, etc., as it is a compress- 
orium and animalcule cage, as well as a 
microscope of seventy-five diameters. The 
metal part is of well finished brass. 
When the mounting of the lens is screwed 
down as far as it will go, the front surface 
of the lens comes in contact with the thick 
glass stage. This latter is beveled around 
the edge, similar to a first-class animalcule 
cage, and when the screw is slightly oiled, 
objects in fluid may be kept for a long 
time, as it is then air-tight, and evaporation 
prevented. The focus of the lens is at its 
plane surface. 
The drawing makes any further descrip- 
tion unnecessary. Allen Y. Mooke. 
Tidare, Gal, July 9, 1878. 
Pond Hunting. 
nnHE writer has frequently, and probably 
in common with many other micro- 
scopists, thought with regret of the truth of 
Mr. Crouch's assertion before the Qiiekett 
Microscopical Club, to the effect that pond 
life is a subject with which American mi- 
croscopists are generally but little ac- 
quainted, Volvox glohator being an un- 
familiar object to many. Granting that 
the volvox is not as common here as in Eng- 
land, as is undoubtedly the case, for the 
writer has, during the last three Summers, 
explored the ponds and ditches consider- 
ably without finding it, the substance of 
the charge is only too true. The reason 
may be urged that the Americans are too 
practical and busy a people to spend time 
exploring puddles and ditches where neither 
funds or fame are to be found, but even 
microscopists find time for amusement now 
and then. The national dislike to walking, 
and an equally characteristic aversion to 
open air pastimes generally, are no doubt 
among the principal reasons for the neglect 
of a flora and fauna full of interest and 
beauty. Oar running streams and still 
lakes alike offer new species to the collector, 
and it certainly seems to the writer that no 
object can sooner bring its reward of ab- 
sorbing interest to the individual, and no 
branch of microscopical study requires less 
previous preparation or accessory apparatus. 
In the course of a walk along Forty- fourth 
street, near the lake shore, Chicago, a short 
time ago, a little pool, barely two yards 
wide, was observed, from which ran a rill of 
not more than a teacupful capacity. A dip 
of the vial brought up at least a dozen little 
green atoms, nothing else but volvox^ while i 
further queries with the dipping bottle re- \ 
suited in a find of the greatest variety of 
animal and vegetable life. Mr. Atwood, 
one of the party, names the following. 
