The indicator. (Pueblo, Colo.) 1894-1911, 1897-05-29

delivered at Leland Stanford, Ir., Uni
versity. by Edward A. Xix:
1T is not my purpose to bclitlc the
service which Is rendered by that IN
comparable. mysterious power which
we call electricity. although may
claim that it has usmpcd the lesiii-
mate plnce of compressed air in many
instances. There is no conflict between
these two great agencies. Each las
It's proper and legitimate field of use
fulness, Independent of the other, and
II Is easy for an intelligent engineer to
recognize these separate rights, and i'll
proportion as he does, so will his work
be successful. A small portion of the
territory of these powers seems 10
overlap and ii is there that we hear
the noise and confusion of disputed
title, and many in the midst of this tur-
moil lose sight of the great mdcpend-
ent domain of each which requires de
vclopmcnt and which will yield rich
return 10 the earnest student and
worker.
Compressed air is the only power
which is alone sufficient to supply all
the power needs of I'm average mine.
For lighting purposes from five to ten
per cent. may, if required. be convert
ed into electricity for that purpose.
where steam or water power Is used,
hfty per cent or more is converted in
To compressed air, and five to ten per
cent. into electricity for lighting.
Where electricity is used. from fifty
per cent. to ninety per cent. is con
vcrted into compressed air. the re-
maindcr being directly used for light
ing.
The reason fer so great conversion
of other powers into compressed air
lies in the fact that generally onc-hall
the entire power is absorbed by pumps,
underground holsts and rock drills.
The two former. in nineteen eases out
of twenty, are actuated by compressed
air and the latter always. Ii is true
that both the hoists and pumps may
he run by electricity economically. but
as yet there has not been produced II
rock drill actuatod by electricity. which
has been II success, and inasmuch rs
air is required for rock drills, and as
they consume more than the pumps
and hoist ms II rule. tile mine manage
mcnt generally concludes to use air for
all three kinds of work rather than in
troducr two kinds of power service
underground.
II am perfectly aware that my state
mcnt regarding the failure of electric
rock drills may be disputed by manu-
factilrcrS of the Su-ca1led article. or by
electrical enthusiasts. but notwitli-
standing all that, shall maintain my
statement true, and 1t will receive the
support of the larger electrical CON
Germs.
ut is true that electric drills have
been made by two or three firms and
on the shop floor they drill very nicely.
at the rate of two inches per minute,
in medium granite, for the first two
feet. From that point on to four and
one half feet. tile average depth of n
blasting hole. their drilling capacity
dcterioratcs very rapidly.
"1'hc air drill does from three to four
time the work easily.
The claim for the electric drill is
that it consumes Int one-third the
power. This is true. but if it takes
three of them to do the work of one air
drill. the wages of six men will have to
he balanced against the wages of two
men and extra power consumption.
The later equals perhaps the pay of
one man. 50 that TO do the same work
with the electric drill would cost twice
more than for the air drill.
There are other considerations. how
ever. independent of this. which mill
tate against the electric drill. viz. that
II will not stand the dust. mud water.
hammer beating and general rough
usage. and again. it would be neccs-
sary to introduce II vcntilating system
for fresh mir, as well as 10 eXpel
smoke, where electric drills are used.
while with the air machines their eX-
haust furnishes all necessary fresh air
and ventilation.
at needs no great disccrnmcnt to
see. therefore, that the simplest and
most desirable proposition, and the one
involving the least machinery and
transformation Of one power into the
other. Is compressed air, which eN-
changes from five to ten per cent. of
itself for lighting purposes only, while
any of the others must make exchange
for ut least fifty per cent. of air and
the lighting beside.
Il have assumed of course. that the
cost of any of these powers delivered
to the mine was equal and the motors
which absorbed them were the most
efficient for the purpose.
IAN things being equal, then. | as
sumo from what have seen of The va
rious requirements of Il mine for pow
cr purposes, and for the reasons given
before that compressed air is the ideal
With varying conditions, however. it
is simply a matter of combining and
comparing the cost of fuel or water.
repairs. interest ON the plant, insur-
ance and taxes. in order to select the
proper general power, and should com
parisnns he nearly equal. then general
utility. simplicity and safety should
decide the choice.
when the preponderancc of evil
dcncc is for one of these forms of pow
or it requires no skill TO make II selcc-
ton but when all things are equal rs
IA COST and maintenance M. unnI.ly "a
in bringing any of the powers to the
mine, then | wish To show why com
pressed air should he the choice with
ont hesitation. and after the choice is
thus made. how TO use it so as TO iusti-
fy the choice.
"Comprcsscd air has been abused in
its use most shamcfully. and until re-
Gently none of It's friends have been
able to he seen or heard. so intensely
has the interest of the world been cen
tered upon the marvellous results of
the investigation in the electrical plle-
nomcna The mysterious has such IL
fascination for the ordinary mind. and
the mctcoiic developments of electrical
science have followed so thick and fast
and in so many fields of usefulness,
that the average individual could ne
stnmpetcd into the electrical camp by
II mere mention of the name OF this
most elusive fluid. Now there has
come Il breathing spell. and the advo-
Gates of compressed air are calling at
tcntion to the fact that compressed air.
properly generated and applied. owns
u place in the economies of the day.
and this they propose to maintain.
Compressed air has generally been
understood to he II most expensive
form of power, and has been given suf-
ferance only because of its utility, since
for underground work II really has no