The wiring diagram as shown in the
illustration will make this a pleasant reality. This wiring may be
applied in numerous like instances. The electric globe may be
located at any desired place and the two point switches are
connected in series with the source of current as shown in the
sketch. The light may be turned on or off at either one of the
switches.
--Contributed by Robert W. Hall, New Haven, Conn.
** How to Make a Bunsen Cell [206]
This kind of a cell produces a high e.m.f. owing to the low
internal resistance. Procure a glass jar such as used for a
gravity battery, or, if one of these cannot be had, get a glazed
vessel of similar construction. Take a piece of sheet zinc large
enough so that when it is rolled up in the shape of a cylinder it
will clear the edge of the jar by about 1/2 in. Solder a wire or
binding-post to the edge of the cylinder for a connection.
[Illustration: Cross Section and Completed Cell]
Secure a small unglazed vessel to fit inside of the zinc, or such
a receptacle as used in a sal ammoniac cell, and fill it with a
strong solution of nitric acid.
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