more sensitive scales, such as fine analytical balances in places where
it is impossible to keep the table or support of the scale level, for
instance on shipboard.

To counteract this effect of the change of level, Dr. Alfred Springer
devised the system which is shown in its most elementary form in Fig. 2.
An additional beam, E, with wire, F, and poise, H, on support, C, were
added to the balance, and connected to it by a jointed connecting piece,
J. The moment of the structure, E C H, about its center of rotation was
made equal to the moment of A C D about the center. The wires, B and F,
are attached at their ends to supports which are both rigidly connected
to the same base or foundation. If this base, the normal position of
which is horizontal, is tipped slightly, the weights, C and H, will both
tend to fall in the same direction. But suppose the right hand end of
the base is raised, causing both of the weights to tip to the left of
the vertical, D, tending to fall over, the left tends to raise the right
hand end of the beam, and the connecting piece, J H, also tending to
fall to the left, tends to lower the left hand end of E and the piece,
J. The moments of the structure, E C H, and A B D being equal, and one
tending to raise J and the other to lower it, the effect will be zero,
and J will remain in its normal position.

It is not at all necessary, however, to have the weights and dimensions
of the structure, E C H, equal to those of A B D. All that is necessary
is that the components of the weight of each part of the structure which
act vertically on J shall be equal and opposite. For, if the left end of
the beam, E, is made shorter than the right end of the beam, A, a given
angle of rotation of the beam, A, will cause a greater-angle of rotation
of E, consequently will tip the weight, H, further from the vertical
than the weight, D, is tipped, and in that case the weight, D, must be