242 THE OPEN BOOK OF NATURE 
a square glass tank, with perhaps a slate bottom, 
and metal uprights, to hold the glass sides and ends 
in position. The glass can be cemented in grooves 
of the uprights with a mixture of red and white 
lead. In stocking your aquarium, some prepara- 
tion must be made for the tenants. Pebbles and 
sand should cover the bottom to the depth of about 
an inch ; pond-weeds should be planted therein, and 
the tank filled with water. Some duckweed will do 
good on the surface of the water, and water-snails 
will keep the inner surface of the glass from being 
covered with scum. The vegetation in the aquarium 
keeps the water oxygenated, and if you arrange 
matters skilfully, there will be no need to change 
the water; but the quantity lost by evaporation 
must be made up from time to time. After your 
aquarium has been occupied by plants for a couple 
of weeks, you can introduce your live-stock, such as 
'Newts, Sticklebacks, Beetles, Water Fleas, Cyclops, 
and so forth. 
For microscopic purposes it is advisable to keep 
special specimens in separate jars, otherwise they 
may disappear into the interiors of voracious newts 
or sticklebacks. Newts make attractive pets ; they 
become quite tame, and may be induced to take 
small worms hanging from the fingers. Pond-life 
is a study in itself, and an extensive literature is 
devoted to it. For beginners two small books in 
the “Young Collector Series” are useful; one is 
‘““Pond-Life (Insects),” by E. A. Butler, and the 
other “ Pond-Life (Alge, Diatoms, etc.),” by 
T. S. Smithson. ‘They are sold at one shilling each. 
Now a few words about Nature photography. 
