TRANSACTIONS OF THE SECTIONS. 181 
mical observations, or by the transmission of time signals from an observatory, must 
be admitted to be great; but those who have had much practical experience in the 
matter are aware of the serious drawback, which in spite of every precaution will 
 oceasionally arise, from failure in the galvanic current, and which necessarily causes 
all the sympathetic clocks to stop. The members of the British Association for the 
Advancement of Science will be gratified to hear of an invention, which sacrifices 
nothing in point of accuracy, and which is nevertheless perfectly exempt from the 
i objection to which we have alluded. 
) For the discovery of this simple and very beautiful method we are indebted to Mr. 
R, L, Jones of Chester, and the first application of it to a large public clock was to 
that of the Liverpool Town Hall. This clock being appealed to by the merchants on 
Change as the standard of time, had subjected them to great inconvenience by its 
inl performance, and at my recommendation the plan of Mr. Jones has been 
adopted with perfect success. The clock in its present state, with the improvements 
which have been made, differs in no respect from an ordinary old turret clock, except 
that the pendulum-bob is a hollow electro-magnetic coi] which passes around perma- 
nent magnets at each oscillation, At each transmission of a current from our normal 
clock at the observatory the coil itself becomes a magnet, and the attraction or re- 
pulsion between it and the permanent magnet prevents the pendulum from oscillating 
except in strict conformity with the pendulum at the observatory. The wire which con- 
nects the Town Hall clock with the clock at the observatory is about one mile in length, 
and the controlling power is so great that a single cell of a Smee’s battery charged with 
very weak acid is sufficient to control the movements of the Town Hall clock, even 
when the pendulum is lengthened or shortened so as to make it lose or gain several 
minutes a day when not under the control of the clock at the observatory. In prac- 
tice, howeyer, the pendulum is regulated to correct time as near as possible, so that 
in the event of the current failing, the clock will not only continue to go, but it is 
liable to the errors only of an ordinary clock, and as an error so small even as a 
fraction of a second is sufficient to show that the current is not controlling or acting, 
the fault may be detected and the remedy applied before the public are subjected to 
any inconvenience. 
_ By this method, therefore, it is quite practicable to make all the public clocks in a 
town, or any number of clocks in a large building, strike, or keep the same time to a 
fraction of a second, withvut the risk of inconvenience by failure of the electric cur- 
_ rent, since all the clocks would go as ordinary clocks should the current fail. This 
- method of controlling the pendulum of a large public clock has been in operation at 
Liverpool for several months past, and the public have an opportunity each hour of 
the day of witnessing the efficiency of the method. In the office window of the Mag- 
netic Telegraph Company, which is within a few yards of the Liverpool Town Hall, 
there is a sympathetic seconds clock, the face of which is exhibited to the public. 
This clock is worked by our normal clock at the observatory, and as the seconds 
hand, at the end of each hour, falls upon the sixtieth second, the first blow of the 
hammer of the Town Hall clock breaks upon the ear, much to the admiration and 
“astonishment of a large number of persons who congregate daily to witness this novel 
performance. 
The normal clock at the observatory is an ordinary astronomical clock, the con- 
ct springs of which are so slight as not to interfere sersibly with its performance. 
_ It will therefore be seen, that by placing a good astrong’ tical clock in any building, 
a turret or any number of clocks may be connected and their movements controlled 
_ by it, and a degree of accuracy secured which has hitherto not been attained. 
On the Mode of rendering Peat economically available as a Fuel, and as a 
™ Source of Illuminating Gas. By J. J. HAyEs. 
_ On the Use of Percussion Lights for preventing Collisions at Sea and on 
og Railways. By Captain Leacu, RZ. 
‘The author introduced the subject by adverting to the fearful loss of life and pro- 
ee rty which annually occurs from collisions at sea; and to the well-known fact that 
_ these collisions generally arise from the want of a proper look-out on beard one or 
