RECENT PROGRESS IN ELECTRICITY. 
175 
have been devised, but perhaps the most interesting of these 
is that of Poliak, which is capable of very high speed. 
In cable work the tendency has also been in the direction 
of increased capital expenditure in the line, with greater in¬ 
crease of speed. Crehore and Squire’s sj^stem of telegraphy 
apparatus for high-speed telegraphy, in which the sine-wave 
method is used, with a number of very important improve¬ 
ments in regard to the mechanical working, has also been 
tried with a very considerable amount of success. 
The problem now before the cable companies is that of 
multiplex working. This is about to be forced upon them 
by developments in wireless telegraphy. The more complete 
study of the phenomena involved in this application of elec¬ 
tricity and the quantitative experiments of the Weather Bu¬ 
reau lead us without any chance for mistake to the conclusion 
that there is no obstacle in the way of transmission over dis¬ 
tances much longer than across the Atlantic, and this with 
the expenditure of an amount of capital quite negligible in 
comparison with the cost of a cable; and we must be prepared 
at any day to learn that that ingenious and indefatigable 
inventor, Signor Marconi, has succeeded in accomplishing 
transatlantic communication, though even then the really 
great problem, that of selective signaling, will still have to 
be solved. Yet no doubt this will come in due time, and the 
only salvation for the cable companies will be in the discov¬ 
ery and utilization of multiplex methods. 
In wireless telegraphy the distance sent is gradually being 
increased, though slowly. I have definitely ascertained that 
the effects are produced by electric radiation, the waves pro¬ 
duced traveling over the surface of the earth in all direc¬ 
tions. In addition to Marconi’s, a number of other systems 
are being developed by Dr. Slaby, Lodge, and others. So 
far, no success has been met with in selective signaling, for, 
though claims have been made in this respect, messages sent 
from the selective stations have been regularly read by out¬ 
side stations. The importance of a non-selective system is 
especially great for navy use, as otherwise the ability of an 
25—Bull. Phil. Soc., Wash., Vol. 14. 
