Dec. 13.] THE NEW ZEALAND GAZETTE. 1885
loss of time. The object of the examination is to discover
the nature of a person's chromatic sense, or sense of colour.
Now, as the fate of the candidate and that of others depend
upon the correctness of the judgment pronounced by the
examiner, and as this judgment should be based upon the
manner in which the candidate stands the trial, it is of im-
portance that this trial should be truly what it ought to be, a
trial of the nature of the chromatic sense, and nothing else--
an end that will be gained if our directions are strictly fol-
lowed. It is not only necessary that the examiner should
carefully observe them--which does not seem to us difficult--
but that he also should take care that the individual ex-
amined does thoroughly what is required of him. This
is not always as easy as one might suppose. If it were only
required to examine people familiar with practical occupa-
tions, and especially with colours, and with no other inter-
est connected with the issue of the examination than to
know whether they are colour-blind or not, the examination
would be uniform and mechanical; but it is required to
examine people of various degrees of culture, all of whom,
besides, have a personal interest in the issue of the examina-
tion. Different people act very differently during the exa-
mination, for many reasons. Some submit to it without the
least suspicion of their defect; others are convinced that they
possess a normal sense. A few only have a consciousness,
or at least some suspicion, of their defect. These last can
often be recognised before examination. They will keep
behind the others, and attentively follow the progress of
the trial, and, if allowed, will willingly remain to the last.
Some are quick, others slow. The former approach uncon-
cernedly and boldly, the latter with over-anxiety, and a
certain dread. Some have been, perhaps, already tested
and have practised in preparation for the trial; others
have never been familiar with colours. Among those already
tested some may be colour-blind. Some of these latter are
uncertain about their colour-vision, and act with great care,
whilst others, again, having been practised in distinguishing
signals, conclude that their colour-sense is perfect. They
make the trial quickly and without thought--of course, regu-
larly making the mistakes characteristic of their special
form of colour-blindness.
The majority, however, desire to perform their task as well
as possible--that is, to do what the normal-eyed does. This,
of course, assists in testing them, provided it does not lead to
too great care, as then the testing is more difficult, the
trouble being that much time is wasted.
Only a very small part have a contrary desire--namely, to
pass for colour-blind, though normal-eyed. We will speak of
these later, and now only concern ourselves with those who
stand the test in good faith with the desire to appear normal,
though perhaps they are colour-blind.
The trial generally goes on rapidly and regularly. We
will only mention those hindrances and peculiarities which
most frequently occur. The examiner must watch that no
mistake is made from not understanding. The names of the
colour need never be used except to ascertain if the name
hides the subjective colour-sensation, or to find the relation
between the name the colour-blind employs and his colour-
perception.
The person examined who thinks more of names than the
test itself (this being generally a sign of school-learning)
selects not only the wools of the same hues--that is, those
of the same colour to his eye--but all which generally have
the name of this colour; for instance, in the first test, I.,
not only the green like the sample, but all that are green;
and with the second test, not only the purple (and what are
generally called red), but all which look reddish, scarlet,
cinnabar, or sealing-wax red. This is of no importance, for
those who only do this have scarcely such defective chro-
matic sense as that with which we are concerned.
Under any circumstance it is better to correct the mis-
takes just mentioned, when arising from misunderstanding,
and it is even necessary, in reference to the mistakes we
explained might occur with the first test. It might be said
that it was sufficient if the examined confounded the test-
colour with green only; that it was indifferent whether he
distinguishes carefully between the various kinds of green.
But, in fact, this is not so unimportant. We must give full
weight as to whether the confusion arises from misunder-
standing or lack of practice with colours, or, finally, from a true
chromatic defect. To include all that is green would render
the test tedious and unpractical. In fact, no little judgment
has been exercised in the selection of the very lightest shade
of the green proposed as a test-colour, for it is exactly what
the colour-blind most readily confounds with the colours
(1-5) of the plate. If the examinee were allowed to depart
from the narrow limits, every shade of green could be in-
cluded, the result of which would be that he would prefer to
select all the vivid shades, and thus avoid the dangerous
ground where his defect would certainly be discovered. This
is why it is necessary to oblige him to keep within certain
limits confining him to pure-green specimens, and, for
greater security, to recommend him to select especially the
lightest shades; for, if he keeps to the darker shades, as
many try to do, he readily passes to other tones, and loses
himself on foreign ground, to the great loss of time, and of
the certainty of the test. What we have just said of green
applies also, of course, to purple (Test II.a).
The principle of our method is to force the examinee to
reveal by an act of his own the nature of his chromatic
sense.
Now, as this act must be kept within certain limits, it is
evident that the examiner must direct him to some extent.
This may present in certain cases some difficulty, as he will
not always be guided, and does either too much or too little.
In both cases the examiner should use his influence, in order
to save time and gain certainty, and this is usually very
easily done. This intervention is, of course, intended to put
the examinee in the true path, and is accomplished in many
ways, according to the case in point.
We will here mention some of the expedients we have
found useful:--
(A.) Interfering when the Candidate selects too many Colours.
It is not always easy to confine the candidate within the
proper limit. In the first test he easily slips a yellow-green
or blue-green skein among the others, and, as soon as there
is one, others follow usually; and it thus happens that in a
few moments he has a whole handful of yellow-green, a
second of blue-green, a third of both these shades at the
same time. Our procedure has assisted us in more than one
case of this kind.
(a.) When the person examined has begun to select shades
of one or several other colours than those of the sample, his
ardour is arrested by taking from him the handful of skeins
he has collected, and asking him whether his eye does not
tell him there are some which do not match the others, in
which case he is told he may restore them to the pile. He
then generally proceeds in one of the following manners:--

1. He rejects one after the other the incorrect skeins, so
   that only the correct remain, which is often only the sample
   skein. He is shown what mistake he has made, and he is
   told only to select skeins of the same hue as the specimen,
   although they may be lighter or darker. If his first error
   arose only from a misconception or want of practice in
   handling colours he begins generally to understand what he
   has to do, and to do properly what is required of him.
2. Or else he selects and rejects immediately the test-skein
   itself. This proves that he sees the difference of colour. He
   is then shown the test-skein as the only correct one, and is
   asked to repeat the trial in a more correct manner. He is
   again put on the right track, as just before, and the trial
   proceeds rightly, unless the error arose from a defect in
   colour-sense. Many seem, however, to experience a natural
   difficulty in distinguishing between yellow-green and blue-
   green, or the dull shades of green and blue. This difficulty
   is, however, more apparent than real, and is corrected usually
   by direct comparison. If the method requiring the name of
   the colour to be given is used a number of mistakes may be
   the result. If a skein of light-green and light-blue alone are
   presented to him, and he is asked to name them, he will
   often call blue green, and green blue. But if in the first
   case a blue skein is immediately shown him he corrects his
   mistake by saying "This is blue," and "that green." In the
   last case the same thing happens mutatis mutandis. This is
   not the place for an explanation. It must suffice to say
   that the error is corrected by a direct comparison between
   the two colours.
   (b). Another Process.--If the candidate place by the side
   of the sample a shade, for instance, of yellow-green, the
   examiner places near this another shade, in which there is
   more yellow, or even a pure yellow, remarking at the same
   time that if the first suit the last must also. The candidate
   usually dissents from this. He is then shown, by selecting
   and classing the intermediate shades, that there is a gradation,
   which will diverge widely if logically carried out as he has
   begun. The same course is followed with colours of the blue
   shades, if the blue-green were first selected. He sees the
   successive gradations, and goes through with this test per-
   fectly if his chromatic sense is correct.
   To ascertain further whether he notices the tints of yellow
   and blue in the green, we can ourselves take the yellow-green
   and blue-green and ask him if he sees any difference in colour
   between them. We can judge by his answer of his sense with
   regard to these shades, and the object of this investigation is
   accomplished.
   It results from all this that many who are finally considered
   to have a normal chromatic sense may occasionally cause
   embarrassment. In the main, the normal observer of this
   kind causes greater loss of time than the colour-blind. It is
   astonishing to see with what rapidity the colour-blind betray
   their defect. At least, it is found, in the majority of the cases
   examined by us, that the first skein of wool selected from the
   pile by the colour-blind in the first test was one of the
   "colours of confusion."