Custer chronicle. [volume] (Custer City, Black Hills, D.T. [S.D.]) 1880-1890, 1889-12-07

NUdt COiOT " tillLs
The speaker was DIR. p. r. Clark. ply
stefan OF the g.. II. and %. railroad
A tall, gangle legged man stood before
q table on which were piled in great
confusion several hundred skeins of diff
ferent colored worsteds They were of
every shade and hue. from pea green to
Mazarin blue, from soiferino red TO
purple. gray, cherry and brown.
The doctor continued: 1.-THE object of
this test is to select the light and dark
shades. Now. I'll go on and select them
frst," and the doctor put all the light
and dark shades running from pea green
to dark green in a little pile by them
selves.
he man watched him closely. and the
greens were all thrown back into the
heap, ard the man began.
Don't let your hand run over the
worsted, hut let your eye do the work.
said the doctor. as the mar began sumb-
ling over the pile.
The man put gray and light yellow
and brown together.
"Thatu do" said the doctor.
"That man is not tit for an engineer,
fireman, brakeman, switchman, con.
ductor. or, in fact, any n who has use
for signals. He is color-blind. That test
alone is sufficient for any railroad. army
or navy.
HIS PECULIAR WEAKNESS.
Now to determine what this mans
chromatic defect is we select a pink
skein.
IF he is red blind he will pick out blues
or ~violets, or both. II he should be green
blind he will select grays and greens OF
blue greens. Sometimes. to verify the
two previous tests. we lay out the red
skein. and the party selects browns or
greens in their different shades"
"What percentage do you find, OF all
those examined. - be color blindy'
About 4 per cent. are color blind.
That is one out OF every twenty-five in
dividuals. There are more red blind than
any other color"
ut is often asked why we don't ex-
anime the men by the lamps. 1t is one
of the most difficult things to stain the
glass regularly. When the glassFis
blown it cannot be made all the same
color, Then. If the glass is thicker the
color will be darker. Again. sometimes
the wick is turned higher, and then the
light has a greater luminosity, while the
other is a very dull light There may be
dust or steam over the glass, and the
light will be darker. A dirty white flag
- .-a oalo~ hl;,,I ayo,,il Ia $~t,a, g. N
green flag. which means safety. They
would take a dirty dark green for red,
which mean danger. This would lead
to endless confusion"
"Do you believe this to be a congenital
defect?'
"Yes: but 1t may also arise from dis.
ease. injuries and the excessive use of
tobacco and alcohol. In one family !
know of four who are color blind, two
brothers and two sisters; in another
family an uncle and a nephew"
do you examine for anything else?"
"Oh. yes. 1t is just as important to
examine for vision and hearing as it is
for color blindness. In order To make the
test for vision this is the programme: A
test plate containing letters that can be
seen at 200 feet and twenty feet, twenty
feet being the normal eye. is placed at
one end of the room.
The room is darkened. The patient
placed twenty feet distant. and then Is
requested TO cover one eye while the
other is being examined. If he sees what
we call twenty twentieths-that Is, the
letters representing twenty fcet-he has
normal vision. Both eyes are put to this
t~est-first the right, her the left. If he
has a vision In both eyes of twenty
tiftieths minus-that is to say. If he can't
see at twenty feet what he ought to see
at tifty--he is rejected. provided glasses
don't improve the vision. IL a man cant
see that big B. the large letter, which he
ought to see at 200, at twenty feet with
only one eye, then he has practically only
one eye. and there have been several ex.
amined who never knew that they could
10 see out Of only one eye."
TESTING FOR HEARING.
.How do you test for hearing"
with my watch The man is requir
ed to cover up his eyes and place my
watch to his ear, gradually removing il
away until the exact distance that hs
can hear the ticking u known. He sayl
y NO when he ceases TO hear It. Now,
two-thirds Of all the engineers are hard
Of hearing, or, better. defective in thu
right ear, which is due to their leaning
out of the cab window, coming in con
slant contact with the wind; that Is t.
say, tie force of the wind coming in con
slant contact with the drum Of the ear Il
becomes affected. The constant pressure
ON the drum Of the ear has the effect Of
~retracting it. II becomes concave. The
range OF vision il also tested. This /
done by placing q man twelve or eight
cen inches from q blackboard. He is re
quested to keep his eye directly N .
chalk spot, which IL or q level with thu
eye, the other eye being closed. He I
directed TO say Yes the momen he seel
any thing moving toward that spot from
above. below. TO the right and TO the left
This constitutes his range Of vision Il
he has any disease or injury to the eys
wa ran alwaya man ont his range Of Wis