THE YOUNG 
softens the upper part. Blow suddenly and 
forcibly, which makes the tube take the shape 
of Fig. 3. Break off the thin, kidney-shaped 
portion almost down to the line a h (Fig. 2), 
A 
Fig. 2. 
and round the edges by heat. Never use a 
tube for connections, or any piece of appar- 
atus, until the ends are smoothed by heating 
in a Bunsen burner. 
B 
Fig. 3. 
To join a tube at right angles to another, 
blow a thin bulb on the end of one tube, and 
break it off close down. This is merely to give 
an expanded end to the tube. On the other 
tube, at the point where the joint is to be made, 
heat intensely with a fine pointed flame, and 
blow out a hole in the side. The expanded 
end of the first tube will fit tolerably well over 
the opening thus made. Stop up two of the 
ends, leaving one open, and join the tubes by 
heat, blowing into the open tube to expand the 
joint as necessary. Do not make the glass 
about the joint too thick, and cool slowly. This 
is one of the most difficult operations to ac- 
complish neatly, but it is of great value in 
many instances. 
SCIENTIST^_ 3^ 
A Ten-Cent Galvanic Battery. 
The interest which at present exists in re- 
gard to telephones, telegraphs, electroplating, 
etc., amongst young people, renders any sim- 
ple and inexpensive method of constructing a 
galvanic battery a matter of great interest and 
importance to a large number. Some years 
ago we constructed a series of cells out of old 
tomato-cans, stiff brown paper, a little plaster 
of Paris, and some discarded sheet zinc that 
had served its day underneath stoves. The 
♦ 
Fig. 1. 
cost of the materials for each cell was but four 
or five cents, the cans being easily obtained for 
the picking up. In our present estimate of the 
cost of the battery, we place no value on the 
cans, for so long as canned fruits, vegetables 
and meats are consumed, the experimenter 
will be able to obtain this part of the apparatus 
without expense, and no fear need be enter- 
teined that the supply will fail, for our readers 
may rest assured that for every one who has 
brains and who will experiment, a hundred 
will be found who have stomachs and who will 
eat. 
Besides the solutions, this battery consists of 
three parts: 1, the can, Fig. 1, which forms the 
outer cell; 2, the porous cell, Fig. 2; and, 3, 
the zinc, Fig. 3. The three parts are shown in 
section, arranged for work, in Fig. 4. 
The can requires little or no preparation. It 
should be cleaned, the remains of the cover 
either cut off or hammered flat, so that the 
edge will be smooth, and a stout copper wire 
should be soldered to one side. 
The porous cell is made thus: Procure 
cylinder of wood or any other material about 
two inches in diameter; round it roll several 
