ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
825 
on account of the distortion produced by the convex sides of the bottle. 
At a trifling cost a small flat aquarium, or large zoophyte trough, may 
be made that will obviate this difficulty. 
Take two pieces of plate glass about 6 in. square, and from a dealer 
in rubber goods obtain a strip of pure rubber packing about 3/4 in. square, 
and so long that when bent into a horse-shoe or U shape the ends will 
just come to the top edge of the glass sides, while the curve shall not 
quite reach the bottom. If the rubber is flush with the lower edge, or 
a trifle below, the tank will not stand firm when finished. This rubber 
strip, bent into proper form, is to be cemented between the two glass 
sides. This may be easiest done by marking on a soft pine board a 
square exactly the size of the glass, and on this square bending the 
rubber strip into a U shape; keep it in position by placing pins or 
tacks, not through, but at the sides of the packing, at various points, 
so as to hold it in shape. Smear the upper side cf the packing tho- 
roughly with cement, lay on one of the glass sides, being careful to 
have it in position, press it firmly on the cement and place a weight 
above it to hold it down, and leave it overnight for the cement to 
harden. Smear the other side of the rubber strip with cement and place 
the other glass upon it, being careful to have the edges of both sides 
parallel. Weight it down, leave to harden as before, and the tank is 
done. The cement that I have used is Van Stain’s Strateria. No doubt 
there are others that would answer the purpose as well. Marine glue 
would probably be better. The rubber packing comes in different sizes, 
from 1/4 to in. in thickness. The aquarium may therefore be varied, 
both in size and transverse depth, to suit the needs and taste of the 
maker.” 
Apparatus for Gathering and Examining Microscopic Objects.* — 
Mr. G. M. Hopkins writes : — •“ One of the difficulties experienced by 
the beginner in microscopy is the finding and gathering of objects for 
examination. As a rule, cumbersome apparatus has been used. The 
conventional apparatus consists of a staff, to which are fitted a knife, a 
spoon, a hook, and a net ; but a great deal can be accomplished with 
far less apparatus than this. 
The engraving (fig. 89) illustrates a simple device by means of 
which the amateur microscopist can supply himself with as much 
material as may be required. It consists of an ordinary tea or dessert- 
spoon, and a wire loop of suitable size to extend around the bowl of the 
spoon, having the ends of the wires bent at right angles and hooked in 
opposite directions. To the loop is fitted a conical cheese-cloth bag, and 
to the bottom of the bag, upon the outside, is attached a strong string, 
which extends over the top and down to the bottom of the bag, where 
it is again fastened. The spoon is inserted between the bent ends of the 
loop and turned, and the point of the bowl is slipped through the loop. 
The instrument is used in the manner shown in fig. 89, that is to 
say, it is scraped along the surface of objects submerged in the water, 
the water passing through the cloth, and the objects being retained by the 
conical bag. When a quantity of material has accumulated, the bag is 
turned inside out by pulling the string, and the pointed end of the bag 
* 
3 M 
1891. 
English Mechanic, liii. (1891) p. 426. 
