RECENT PROGRESS IN ELECTRICITY. 
177 
presence of these exponential terms will prevent speech 
through long distances just as at present, so that without 
other improvements at present unknown the distance may be 
lengthened say 50 or 100 per cent, but by no means indefi¬ 
nitely. Put in another way, when a note is being trans¬ 
mitted through the cable each element of the cable is charged 
to a given potential, and this charge represents energy, and 
a sufficient amount of energy to supply all these elements 
must be furnished by the transmitter before speech will be 
received at the other end. This means that the telephone 
diaphragm must keep on vibrating for a period of time before 
the note is received at the other end. But, even as it stands, 
the invention is of the very greatest importance to the tele¬ 
phone companies. 
ELECTRO-CHEMISTRY. 
No very striking advances have been made in this line 
during the past year, if we except the commercial production 
of artificial graphite by Mr. Atkinson. This is produced by 
heating carbon with a certain per cent of iron (carbon being 
converted with great difficulty when pure, but quite readily 
in the presence of impurities) which need not necessarily re¬ 
main, but may be volatilized. 
The production of electrolytic soda, phosphorus, etc., seems 
to be now firmly established on a dividend-paying basis. 
Aluminum has attracted attention in entering the field in 
competition with copper for electrical purposes. It is doubt¬ 
ful, however, if it will be used to any extent, on account of 
its poor mechanical qualities, it being more allied to tin and 
lead than to the stronger metals. It is possible, however, 
that alloys with magnesium may give this needed strength 
without loss of electrical properties, in which case a consid¬ 
erable use will be made of it. Magnesium could be very 
easily and cheaply produced, much more cheaply than alu¬ 
minum, the present high price being due merely to the small 
demand, and there may be a future for these and similar 
alloys, as, for example, beryllium and aluminum, or magne¬ 
sium, which I have called Austin metal. Even at present, 
