1879J Proceedings of Societies . 579 
cording barrel is then set to the time and the wheelwork set in 
motion. The complete setting occupies only a few minutes. 
Physical Society, June 14, 1879. — Prof. W. G. Adams, 
President, in the chair. 
Prof. Macleod described a plan for Suppressing the Induction 
Disturbances in a Telephone Circuit. The method suggested 
is the employment of a shunt consisting of a cell containing 
platinum plates or wires in very dilute sulphuric acid. The in- 
duction currents on the line, having a high potential, escape 
through the shunt to earth, while some of the telephonic current 
passes to the telephone. In this way the induction currents 
are entirely removed, while the sound of the voice is only 
weakened. 
Dr. O. J. Lodge exhibited his New Reversing Key for 
Electrometer Work, which is preferable to the ordinary forms, 
as giving a high insulation, small capacity, and not requiring 
the hand to approach close to it to work it. It consists of four 
platinum wires, arranged in pairs crossing one another ; one 
pair crossing between the other two. These are the terminals 
and contaCt pieces of the key. The middle pair are supported 
by an endless silk thread, which runs on two pulleys, one of 
which is fitted with a handle. On turning the handle to right or 
left the two middle wires are brought into contaCt with one or 
other of the two outer wires, and the current reversed at will. 
The whole is enclosed in a metal box. 
Mr. J. F. Moulton then demonstrated the results of the 
experiments of Mr. Spottiswoode and himself on the Sensitive- 
ness of EleClric Discharges in vacuum tubes (see “ Monthly 
Journal of Science,” 3rd series, vol. i., p. 443). 
June 26. — Earl Rosse in the chair. 
An extra meeting of this Society was held on the above date 
at Cooper’s Hill Indian Engineering College on the invitation of 
Col. Chesney, R.E. 
Prof. Unwin, of the College, read a paper on “ Experiments 
Relating to the FriCtion of Fluids on Solid Surfaces against 
which they rub.” It has long been known that a board dragged 
through water suffers a resistance varying in some way as the 
square of the velocity, that a stream has a uniform motion at 
such a velocity that the component of the weight of the water 
down its inclined bed is balanced by the fractional drag on the 
bottom. The fluid in the neighbourhood of the stream is known 
not to move as a solid mass, the centre moving faster than the 
sides, and the different fluid layers rub against each other. The 
adhesion of the fluid to the solid, against which it moves, also 
gives rise to a sliding or shearing aCtion. Our knowledge of the 
subject has hitherto been gained from observations on pipes, 
streams, and from the experiments of the late Mr. Froude with 
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