404 
greater success, for permission to lay a cable between Dover 
and Calais. On August 10, 1849, Louis Napoleon granted 
them an absolute monopoly for ten years, provided that the wire 
was laid by September 1, 1850. Before this date a telegraph 
wire under the Channel became an accomplished fact, and 
messages were certainly transmitted through it, although they 
seem to have been slightly incoherent. The glory of this tele- 
graph was, unfortunately, short-lived, for after the first evening 
it maintained an obstinate reserve, and ‘‘ spoke no more.” 
The next year another concession was granted to the Bretts by 
the French Government, and on the strength of this the Sub- 
marine Telegraph Company was formed. But 4300 was all 
the public would subscribe, as it had already been conclusively 
proved that submarine telegraphy was an impossibility. Happily 
Mr. Crampton came to the rescue, while Mr. Kiiper suggested 
armouring the insulated conductor with iron sheathing—a pro- 
posal also made by Willoughby Smith. Once more England 
and France were electrically connected, and on November 13, 
1851, the public sent a message through a submarine cable for 
the first time in the history of the world. 
The Bretts then applied to the Government for a monopoly to 
electrically connect England and Ireland. Prof. Ayrton read 
out the original replies they received on this occasion, in which 
each Government department in turn complimented the brothers 
on their perseverance and success, but regretted that the matter 
did not lie in their power, and referred them ‘‘ next door.” The 
laughter that was here heard among the audience was presumably 
due to the striking contrast this afforded with the promptness 
and celerity of Government procedure of to-day ? 
As early as 1844 Morse had written to the American Treasury : 
‘“My experience is that telegraphic communication on the 
electromagnet plan might certainly be established across the 
Atlantic Ocean.” Nothing was done in the matter until 1855, 
when a syndicate was formed, and in the following year Cyrus 
Field crossed over to England, where he signed an agreement 
with J. W. Brett, Charles Bright, and E. Whitehouse to start 
an Atlantic Telegraph Company. 
Great difficulties foreshadowed the working of an Atlantic 
cable, due to the retardation of the signals. In connection with 
this subject, the lecturer stated the very different values which had 
been assigned by Wheatstone, Latimer Clark, and others to the 
velocity of electricity, before it had been deduced from a paper of 
Lord Kelvin’s, in 1855, that electricity had no velocity in the 
ordinary sense of the word. 
A mechanical model was shown illustrating the difference 
between the sudden opening of a door by a ball projected at it 
with a certain velocity, and the gadua/ opening of the door by the 
eradual increase of the pull at the other end of a long piece of 
india-rubber—the latter method being comparable with the action 
of an electric current. Experiments were also made on a water 
cable, and it was shown that by combining resistance and 
capacity, waves of water travelling in opposite directions could 
exist at the same time in a tube ; also that if positive and nega- 
tive pressures were alternately applied on one end of the tube, 
with an interval of time less than thirteen seconds between their 
application, no effect whatever could be detected at the other 
end of the tube, a distance of seven feet. The spots from three 
very dead-beat galvanometers, placed respectively at the sending, 
middle, and receiving end of an artificial Pacific cable, were then 
projected on the screen, and the gradual rise of current along 
the cable was made visible to every one, the current at the 
distant end taking six seconds to reach its steady value. 
The lecturer here mentioned Fourier’s Théorie Analylique de 
Ja Chaleur, published in 1822, which ‘‘ mathematical poem,” 
though written long before cables were dreamt of, enabled Kelvin 
thirty years later to attack a problem, the successful solution 
of which has created submarine telegraphy. For two other 
important conclusions were deduced from Kelvin’s 1855 paper, 
namely, that the time elapsing before the current began to 
appear at the other end of a cable, only depended on the pro- 
duct of the resistance of the conductor into the electrostatic 
capacity, and practically not at all on the battery power. Also 
that the retardation of the signals was proportional to the square 
of the length. The first of these results was opposed to the 
opinion of such well-known engineers as Sir Charles, and Edward, 
Bright, who considered that the velocity of electricity varied 
with the use of high potential frictional, or of low potential voltaic 
electricity. From his own theory Kelvin calculated that the 
probable speed of signalling through the proposed Atlantic cable 
would be at the rate of three words a minute, which was sub- 
NO. 1426, VOL. 55] 
WALTORE 
[FEBRUARY 25, 1897 
sequently found to be obtainable with his mirror galvanometer. 
Siemens, however, feared that only one word a minute could 
be sent, while Charles Bright, from experiments on 2000 miles 
of underground conductor, predicted ten or twelve. 
Meanwhile the Atlantic Telegraph Company had been suc- 
cessful in their efforts, for in 1857 the U.S. frigate Vagara 
and H.M.S. Agamemnon started from Valentia with 2500 miles 
of cable coiled in their holds. About a tenth part of this was 
payed out, and then the wire broke in deep water ; and so ended 
the first attempt to lay an Atlantic cable. The following year a 
second expedition started, and after several failures this cable was 
successfully laid, and England first spoke electrically to America. 
The life of this cable was, however, pitifully short ; the signals 
grew weaker and weaker, and after one little month it died. It 
was not, indeed, until 1866 that a complete cable was laid by 
the Telegraph Construction and Maintenance Company, which 
also in the same year captured a cable that had been previously 
broken and lost. Thus two good cables were completed between 
England and America. 
Prof. Ayrton then described the siphon recorder in some 
detail, and exhibited the earliest example of that instrument, 
constructed in 1870. Later forms were also shown, in which 
the electrified ink was replaced by the use of a vibrating siphon. 
The system of automatic sending was explained, and the question 
of signalling briefly considered, diagrams being thrown on the 
screen illustrative of the effect of condensers and of curbing in 
obtaining sharp signals. The word ‘‘ imperial’ was sent by an 
automatic sender at the rate of seventy-two letters a minute 
through the artificial Pacific cable in four different ways: (1) 
with no curbing nor condensers at either end ; (2) with curbing 
only ; (3) with condensers only; (4) with curbing and con- 
densers at both ends of the cable. 
Before concluding his lecture, Prof. Ayrton, not content with 
having his subject limited to the space of sixty years, looked 
ahead and saw, or rather failed to see, the cables of the future. 
For it is his belief that in the days to come copper conductors, 
gutta-percha insulation, and iron wire-sheathing will be relegated 
to the museum of antiquity, and when a person wishes to tele- 
graph to a friend, he knows not where, he will call to him in an 
electromagnetic voice, which will be heard distinctly by him who 
has the electromagnetic ear, but will be silent to every one else ! 
The hall was hung with the portraits of the chief of the early 
workers in submarine telegraphy, each in its turn being illum- 
inated with a projector when reference was made to it; the 
lecture was illustrated with historical letters and documents, 
specimens of all the important early cables, as well as of the 
latest, hydraulic and other models; and an artificial cable elec- 
trically 3600 miles long, fitted up with signalling apparatus at 
each end, was shown through the kindness of Dr. A. Muirhead. 
Mr. Preece was unfortunately absent through illness, but his 
place as Chairman was filled by Sir Henry Mance. Thus 
a compensation was afforded in having an opportunity of 
admiring not Mance’s method of finding faults, but his method 
of finding merits in Prof. Ayrton’s sixty years of cable. 
THE VALUE OF IRRIGATION CANALS IN 
INDIA. 
THE deplorable state of large districts in India at the present 
time is attracting a great deal of attention, owing to the 
famine which is devastating the country, caused by the failure 
of the crops from the drought and want of rain, Under such 
conditions, every drop of water is as precious as gold, and the 
canal authorities have to strain every nerve to make the avail- 
able water supply spread as far as possible. Any information 
bearing on the canals cannot fail, at such a time, to be of in- 
terest. A return recently issued by the Public Works Depart- 
ment bears testimony not only to the great benefit that has 
already been conferred on India by the system of irrigation 
pursued during recent years by the Indian Government, but 
also shows that these works have been a financial success. 
Lord Lansdowne is reported strongly to have urged that 
public works of irrigation do more good than any other form of 
public works; and it is a matter of regret that more has not 
been done in the past in the matter of canal construction. The 
total area irrigated in India from Government works is about 
134 millions of acres, the estimated value of the crops raised 
on this area amounting to 37,000,000/., taking a crore of 
