25G 
L. Schwendler —Telegraphy with Fractional Currents. [Nov. 
2. On a simple method of using an insignificant Fraction of the Main Cur¬ 
rent, produced by a JDynamo-Flectric Machine for Telegraph pur¬ 
poses.—By Louis Schwendler, m. i. c. e. &c., &c. 
(Abstract.) 
The author pointed out that up to the present the electric currents 
required for Telegraph signalling were chiefly produced by galvanic Bat¬ 
teries, a method comparatively expensive and also connected with cumbersome 
arrangements. Since his Electric light experiments, instituted last year in 
London by order of the Secretary of State for India, he had always been 
of opinion that it would be of technical as well as of economical importance 
if the strong, constant and exceedingly cheap currents, produced by the pre¬ 
sent construction of Dynamo-Electric machines, could be made available for 
signalling purposes. However Mr. Schwendler found at the time, that there 
were some difficulties in the way, which he believed he had now overcome ; 
and having of late made some experiments on the subject, he did not 
hesitate to communicate the results. His method is a very simyile and 
ingenious one. A strong current is produced through a comparatively 
small resistance by a Dynamo-Electric machine, which is an arrangement 
for converting Mechanical Bower direct into Magnetism and Flectricity 
according to the well known laws of Faraday’s Magneto-Induction. This 
strong main current, so produced, is made use of for doing any kind of 
useful work. For instance, during night the useful work done by the main 
current may be given out as a powerful Electric Light to illuminate the 
signalling office ; or during day-time the strong main current may be em¬ 
ployed to drive an Electro-Magnetic Engine which, in its turn, is used for¬ 
doing any kind of useful mechanical work, as pulling the punkhas, produc¬ 
ing a draft of refreshing cool air through the building, lifting messages, 
&c. &c.; or the main current may be sent through a large galvanoplastic 
apparatus in use, say, at the Surveyor General’s Office &c., &c. Thus a 
strong electric current becomes available, the production of which is wholly 
or partly repaid by the useful work it is able to execute in a variety of 
ways as indicated. 
On the other hand the electric currents required for signalling pur¬ 
poses are exceedingly weak as compared with the strong main current. 
Hence the Electric currents may be supplied to the Telegraph lines, by 
simply tapping the main current without perceptibly reducing it, or with¬ 
out influencing the useful work done by the main current. This is the 
method Mr. Schwendler proposes. He said : “ This might be an induce¬ 
ment for Telegraph administrations to come forward more quickly with the 
introduction of the Electric Light in their Signalling offices, since they would 
