The workingman's advocate. [volume] (Chicago [Ill.]) 1864-1877, 1874-02-28

OF the mine, and separates fiery districts
INTO distinct divisions, with separate cur
rents of air to each The law of Ohio pro
vides for 100 cubic feet per man per min.
ute, which Is sufficient if properly distribu.
ted, to ventilate any mine in the United
States in present operation.
There Is seldom adequate provision made
for the proper distribution Of air. AR
cases are often too far behind trap doors !,
are not hung where they should be, ana
too frequently when hung, they are SO
slovenly built as to leak arr at an Ii'"os
The manner of the distribution 81 the AZ
IN uine will. at all times, distinguish .,,e
gsnuipe miner from the blunder'"s
! cate :.,r,,ments used
There are a number Of instruments "'ou
-, mines in connection win 'V"'h"N"",
- .h;ah n the hands IF capable men, are 1T
NV great service III maintaining the by
Genie state Of the atmosphere The ane-
mometer is used to measure the speed at
which the air passes along the galleries.
Blranes thermometer is chiefly used in
England, while that of NJ. Cormes is mann
ly used III Belgium, France and Germany
BiTanes instrument is a portable machine,
the registering apparatus being IN front Of
the revolving wheel. There are siX small
circles, marked from ten To one hundred in
Roman numerals. The y index ascertains
i'll one revolution the amount multiplied by
itself. Each indice does the same So that
the amount of air passing Is read IN the
same manner as the hands of clock indl-
cate the time of day. In NJ Cormes' III
strument, by pulling string attached for
the purpose, the apparatus can be thrown
out of gear. The French machine is said
to give more satisfactory results than that
Of Blrane
The barometer is employed under ground
to note the pressure OF the atmosphere N
the various stages Of the weather In
mines which yield fire damp copiuusly. any
lessening of the atmospheric pressure. as
Indicated by q fall Of the barometer, Is a
sure presa5e Of an increasing escape al tire
damp. 81 long AS the barometer stands
steady there is uniform discharge VI in
tiammable alr-nothing is evolved except
the ordinary making OF tile mine ;-hut
when the pressure Of the atmosphere Is
lessened, an undue proportion III hrr damp
escapes IN proportion to the c1unterpOisiiig
pressure. Renewed attention Is forthwith
given, IN fall Of the mercurial column,
to the state al the AIR, IN mines under the
control OF capable and careful managers
and while the mightIest efforts of man
have not always been able 10 prevent eN-
plOslUns OF ire damp, 1t Is beyond any
question Of doubt that great majority "a
| these awful disasters are due to the I-uU
rance Of the laws which govern its acuu
mutation on the part of the persons cu
1 trusted with the management of mines
The barometer IA also frequently used t,
ascertain the friction Of air along the air
courses AneroId baromcters are bes
adapted to this purpose, ana are generally
preferred.
The thermometer is expected to ascer
tain the temperature Of the air Of mines
BY placing thermometer in duW meas
shaft and one in the upcast, the dItferenc,
IN the heat Of the ar is made known, from
whence the amount Of ventIlatlng pIessur,
Is calculated The thermometer serves
many other useful purposes in the mine
theNariOus temperatures If different mines
or Of places in the same mine, ard the hea
uf the column Of upcast air IN every par
~ the shaft. etc, are ascertained by it.
The water guage IS another useful III
strunent In underground lie, and is EN-
ployed to enable the superIntendents q
measure the amount Of pressure which i:
lost by the fractional resistance OF AR ii
its passage along the airway. This instru-
ment is a glass tube Of the slope Of tn,
letter I, having graduated scale of niche:
and parts Of inches marked Oh 1t, for the
purpose Of measuring the difference Of the
height Of water IN the respective tubes.
The hygrometer finds the amount 81
moisture in the air of mines, whence it:
density and heating powers are ascer,ined
The return air Is always more Or les!
saturated with the vapor If water, whict
renders it lighter than dry air, and conse
quently impairs its ventilating power
until it has reached the furnace at the up
cast shaft. In the employment Of thes,
instruments, by competent underground
superintendent, valuable aid is rendered
touching the safety Of the mine, and tn,
lives and health Of the miners.