Evening star. [volume] (Washington, D.C.) 1854-1972, 1892-08-06
And Tobacco AmblyOp!a.

FROM the raj. Mali 6aZatte-
The report OF the committee Of the Royal
Society on color VISION" with the accompany
ing minutes, contains some curious reading.
The most practically important fact brought
out is that some Of the tests now used for de-
tecting defects Of vision in engine drivers
and seamen are inefficient Color-blind men
are actually educated to pass the examinations,
profession of what may be called color
coaches" having grown up to supply this wan:
The art OF examining surely never had
more strange and. one may add. q more
mischievous application than this. The
committee had before them one Of these
gentlemen. but they do not give his evidence
Another witness, however, explains their method
OF proceeding. They provide them elves with
a set OF colors similar to those used in testing
A color is shown to the pupil. 1t is say. green
and he calls i. red" Thereupon he is instructed
to answer green" when thing appears to him
red. The instruction is not. of course. SO SIM
pie as this would seem to make il out. The color
sensations are various in various individuals and
different tints make different impressions; but
the example is sufficient to chow the method of
''color coaching" The committee recommends
the universal and compulsory use Of what is
called "Holmgren's test" This consists of a
number of skeins of colored wool The exam
liner selects a skein Ct certain color-say pale
grass greenland the candidate is requested to
pick out from the heap others of the came type
of color, irrespective of shade. A color-blind
person will match drabs, pinks and yellows with
grass green, blues and violets with light pur-
pie or rose, and dark green or light green with
light red, according rs he is ''red blind or
''green blind"
That accidents have happened either from
the inefticiency of the test applied or from none
having been applied at all seems to be estab-
lished beyond doubt. In July, 1875. q steam
tug and a steamer collided near Norfolk Va
The master of the tug swore that the steamer
red light was exhibited All the officers Of the
steamer swore that the position of their vessel
was such that only the green light could have
been visible to the tug. The master of the tug
was found on examination to be color blind.
In this case the defect cost the lives Of ten par
sons. In another case an accident was narrowly
averted. The third officer of vessel, seeing
what he supposed to be green light in an APP
preaching ship, called the man at the wheel
to port" Happily the captain was on
deck and countermanded the order. It turned
out that the man.was color blind. He was re-
moved from that ship, but probably followed
his occupation elsewhere. A somewhat alarm
ing fact is that temporary color blindness may
be brought on by excessive smoking. Tobacco
amblyopia it is called and it may be brought
on or was brought on in @ cnse described, by
smoking half an ounce Of shag daily" not an
when the cause is removed.
As to the frequency Of color blindness there
seems to be variety Of opinion OF, possibly, Of
experience. Hoimgren found o percentage Of
little more that three in the 49, men that
he examined. But in 2l4 lads examined for
naval cadetships in 1888 only one color blind
was found, and in the two following years the
percentage was only l.02 and 1.8l II Is curl
Gus to be told that hundred girls can be tested
in the same time Is forty boys. Probably they
are quicker and more docile; but another Wit
ness tells us that color blindness b very rare