APRIL 7.] THE NEW ZEALAND GAZETTE. 593

lington, but the Examiner should report the candidate as having failed in form-vision, and in forwarding the usual papers a description of the colours of the pellets incorrectly selected as matches in the respective tests, with any remarks, should be given on the Form Exn. 17c, in the space allotted for the incorrect wools.

(12.) The result of every test in form-vision is to be reported to the Marine Department on the Form Exn. 2, and on Form Exn. 14 when the candidate is up for examination for a certificate, and on Form Exn. 2b when the candidate is up for examination in colours only.

All cases of failure to pass the test are also to be reported to the Marine Department on Form Exn. 17B.

2.—COLOUR-VISION TEST.

(1.) The colour-vision of candidates is to be tested by means of Holmgren’s wools.

The wools are always to be kept in the tins provided for the purpose, except when in use at an examination, in order that they may not become faded or dirty. Each set contains about 135 skeins of wool.

(2.) Before the examination commences the skeins should be separated from one another, but each separate skein should be kept tied up as when first received.

The three test-skeins are labelled respectively I. (light-green), IIa. (pink or light-purple), and IIb. (red), and they are always to be used in the order mentioned.

Care must be taken that the labels do not get detached.

The colour-vision test should be held only by daylight. If a good natural light is not obtainable, and artificial light has to be used, the test must be postponed. When the weather is dark or foggy, and a candidate cannot be examined in colours before his examination in navigation commences, he may be allowed to proceed with the examination in navigation provided he is examined in colours on the first available opportunity.*

Full instructions as to the conduct of the examination will be found herein.

(3.) The Examiner, as the examination proceeds, should carefully place on one side the skeins the selection of which by the candidate seems to indicate a defect in colour-vision, taking care to discriminate between those selected as matching the first test-skein, those selected as matching the second test-skein, and those selected as matching the third test-skein.

The skeins which have been correctly selected should be returned to the general heap on the completion of each of the three tests.

(4.) In every case in which the Examiner rejects a candidate, or is in doubt as to whether he should reject him or not, he is, when the examination is finished, to cut a small piece (say, an inch) off every one of the actual skeins incorrectly selected by the candidate, and to stitch the pieces cut off on to Form Exn. 17c, keeping the pieces cut off the skeins selected as matches to the first test-skein in one line, the pieces cut off the skeins selected as matches to the second test-skein in another line, and the pieces cut off the skeins selected as matches to the third test-skein in a third line on the form. The form (Form Exn. 17c), with the pieces of wool attached to it, is then to be forwarded to the Marine Department, with the Examiner’s report, on Form Exn. 17B.

The greatest care must be taken that the pieces forwarded are cut off the actual skeins selected by the candidate, in order that there may be a reliable record of the actual selections made by the candidate if any question should subsequently arise.

Pieces need not be cut off the test-skeins, but only off the skeins incorrectly selected by the candidate.

(5.) In cases in which the candidate passes the test, pieces need not be cut off the skeins he has selected.

(6.) When the candidate makes incorrect matches the Examiner should, after each of the three tests, hold up the skeins selected, and ask the candidate if he is satisfied that they all match the test-skein. If he is not satisfied he may be allowed to withdraw any of the skeins he pleases.

(7.) During the test for colour-blindness the Examiner should avoid naming the colours of any of the wools, and should explain to the candidate that he does not require them to be named to him.

In the test for colour-ignorance the candidate has to name three colours. (See under heading “Colour-ignorance Test.”)

(8.) As soon as any skein becomes discoloured, or unduly reduced in size (say by one-third) owing to pieces having been cut off it, the matter should be reported to the Marine Department.

(9.) In the remarks which follow reference is made to different kinds of colour-blindness (red-blindness and green-blindness), but the Examiner is not required to form any conclusion as to the kind of colour-blindness from which the candidate suffers, and should not offer the candidate any opinion on this point.

All that is required is that the Examiner shall conduct the examination according to the rules laid down, and from the wools selected judge whether the candidate is or is not colour-blind, the nature of his colour-blindness being immaterial.

(10.) The result of every test should be reported to the Marine Department on the Form Exn. 2, and on Form Exn. 14 when the candidate is up for examination for a certificate of competency, and on the Form Exn. 2b when the candidate is up for examination in colours only.

All cases of failure should also be reported to the Marine Department on Form Exn. 17B, to which should be attached Form Exn. 17c, containing the pieces of the wools incorrectly selected by the candidate. (See par. 4.)

Holmgren’s Method of Testing for Colour.

The method of testing consists in asking the candidate to select from variously-coloured objects those which appear of the same colour as one which the Examiner selects. The most suitable objects and at the same time the most readily obtainable are skeins of wool, which can be procured of almost every desired hue and tone. An advantage of skeins of wool, besides their portability, is that, owing to their want of gloss, they appear of approximately the same tone from whichever side they are viewed. The colours of the skeins to be selected include reds, oranges, yellows, yellowish-greens, pure greens, blue-greens, blues, violets, purples, pinks, browns, and greys. Several shades of each colour, with at least five graduations of each tint, are provided, from the deepest to the lightest greens and greys. Varieties of pinks, blues, and violets, and of light-grey, together with shades of brown, yellow, red, and pink, are well represented. The test-skeins with which the examinees are to compare the other skeins are three in number—(1) a light-green, (2) a pink or pale-purple, and (3) a bright-red. These three colours will suffice to indicate approximately the amount and kind of colour blindness which may exist. The light-green skein, which is a tolerably pure green mixed with a large proportion of white, is chosen as the colour which closely matches the spectrum colour which the red- and green-blind distinguish as white or grey. It is chosen of a pale tint, as it then becomes puzzling to the colour-blind to distinguish its colour by luminosity. A light-grey or drab skein will represent the same brightness to him that this pale colour does, and, although he may be trained to distinguish bright colours by their relative luminosities, in the case of these pale varieties he will be unable to do so. The pink or light-purple is chosen for similar reasons, and in fact it is nearly a complementary colour to the green. The purple is, according to the Young-Helmholtz theory, a mixture of two fundamental colours, the blue and the red, and, as in the green-blind it excites both the blue and red sensations, it may be confused with grey, or with a green. In the red-colour-blind it excites in excess the blue sensations mixed with what they call white. A blue or violet may therefore be matched with it.

The method of examination is as follows:—

The wools are placed in a heap on a large table covered by a white cloth or white paper, and in broad daylight. The first test-skein is taken from the pile, and laid far enough away from the others not to be confounded with them during the examination. The person examined is requested to look carefully at the test-skein, and then to select other skeins from the pile most nearly resembling it in colour, and to place them by the side of the sample. At the outset, it is necessary that he should thoroughly understand that he is required to search the heap for the skeins which make an impression on his chromatic sense or sense of colour similar to that made by the test-skein, and quite independently of any name he may give the colour. The Examiner should explain that resemblance in every respect is not necessary—that there are no two specimens exactly alike; that the only question is the resemblance of the colour; and that, consequently, the candidate must endeavour to find something similar in shade and something lighter and something darker of the same colour. If the person examined cannot succeed in understanding this by a verbal examination, resort must be had to action. The Examiner should himself pick out the skeins, thereby showing in a practical manner what is meant by a shade, and then restore the whole to the pile, except the sample skein. As it would require too much time to examine every individual in this way, it is advisable, when examining large numbers, to instruct them all at once, and to ask them to attentively observe the examination of those preceding them, so as to become more familiar themselves with the process. This saves time, and there is no loss of security, for no one with a defective chromatic sense will be able to find the correct skeins in the heap the more easily from

• When the examination in navigation precedes the colour-tests the candidates should be informed that the examination in navigation will count for nothing if they should fail to pass the colour-tests.

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