eld in reserve. All the dynamos are grouped for
quantity.

[Illustration: FIG. 3.--GENERAL PLAN OF THE ELECTRIC WORKS.]

The company at present owns six closed and five open cars. In the former
there is room for twenty-two persons. The weight of these cars varies
between 3,500 and 4,000 kilos.--_La Lumiere Electrique._

* * * * *

By the addition of ten parts of collodion to fifteen of creasote (says the
_Revue de Therap._) a sort of jelly is obtained which is more convenient
to apply to decayed teeth than is creasote in its liquid form.

* * * * *

POSSIBILITIES OF THE TELEPHONE.

The meeting of the American Association was one of unusual interest and
importance to the members of Section B. This is to be attributed not only
to the unusually large attendance of American physicists, but also to the
presence of a number of distinguished members of the British Association,
who have contributed to the success of the meetings not only by presenting
papers, but by entering freely into the discussions. In particular the
section was fortunate in having the presence of Sir William Thomson, to
whom more than to any one else we owe the successful operation of the
great ocean cables, and who stands with Helmholtz first among living
physicists. Whenever he entered any of the discussions, all were benefited
by the clearness and suggestiveness of his remarks.

Professor A. Graham Bell, the inventor of the telephone, read a paper
giving a possible method of communication between ships at sea. The simple
experiment that illustrates the method which he proposed is as follows:
Take a basin of water, introduce into it, at two widely separated points,
the two terminals of a battery circuit which contains an interrupter,
making and breaking the circuit very rapidly. Now at two other points
touch the water with the terminals of a circuit containing a telephone. A
sound will be heard, except when the two telephone terminals touch the
water at points where the potential is the same. In this way the
equipotential lines can easily be picked out. Now to apply this to the
case of a ship at sea: Suppose one ship to be provided with a dynamo
machine generating a powerful current, and let one terminal enter the
water at the prow of the ship, and the other to be carefully insulated,
except at its end, and be trailed behind the ship, making connection with
the sea at a consi