GENERAL CONCLUSIONS. The percentage difference both in the output and quality marks for the work done under the different systems appears to be too small and inconsiderable for any final decision to be given as to the relative results of the systems of lighting. On the other hand, the differences obtained in these experiments were greater than those found in the reading or spotting" test, and the opinions obtained from the workers are a useful guide in forming conclusions as to the relative merits of the different lighting systems. 66 It appears that the time worked continuously for each experiment should be considerably extended, as the steady rate of output had not been reached, and definite signs of fatigue-(sufficient to influence the output and quality appreciably) had not really set in. Also it might be desirable to have more than three operators, and thus obtain a more reliable average of output. The following extract from a letter written after the conclusion of the experiments gives the general impressions of the operators : 66 Though we made buttonholes the whole week, we did not weary of them at all; I think they were an excellent subject for experiment. Our main sensation from Monday morning till Thursday night was one of light starvation, and I think this affected the whole experiment. Even in the so-called daylight tests we were so starved of light that it was a constant strain—especially in the black work. If you look at the work we did you can see that we were half-blind all the time. Towards the end of the week our eyes ached badly-a cumulative ache which was not merely the result of the current test. 66 Another very strong impression under the direct lighting tests was that of being shut in. This was due, I think, to the extraordinary contrast between the dark surroundings and the bright patch on our work. This was more trying than one can quite explain, and affected us mentally-giving a sort of imprisoned, hypnotised, shut-in feeling which was very trying. This was, I feel sure, one reason why we did so well comparatively under the mixed lighting during the direct tests—it was not because the mixed light in itself was good, but because we could look up for a second, and relieve the eye strain without the eye having to re-adjust itself on returning to the work. On the other hand, in full artificial light, the surrounding darkness acted like a nagging foreman, and kept us at it,' with the result that for the short period of the test we increased output far above what we could have kept up in that light for any length of time. It would have been most interesting if some test for exhaustion could have been devised which could have measured our fatigue at the close of each test. We were agreed that we felt far more played out after the full artificial period than after the mixed lighting period when the light was direct. But on Friday, when the light was semi-indirect the opposite was the case. Friday was a tremendous relief, and it was not by any means because we were back on white material. It was chiefly the semi-indirect light, I feel sure, for our eyes were thoroughly tired out, and we ought to have produced less work. The relief was not merely physical, there was a change of general outlook. I wish we could have followed up the semi-indirect tests for longer, and I wish, too, we could have worked on the basis of what the girls persisted in calling 'real daylight,' as compared with the ecclesiastical gloom which was substituted for that." APPENDIX V. EXPERIMENTAL APPARATUS FOR THE LIGHTING OF An attempt was made to devise some form of apparatus which would provide a suitable light for use in the process of glass-bevelling, while avoiding all possibility of glare. All the operatives questioned agreed that the best conditions were those in which it was possible to view the glass against the clear sky, and an attempt was made to imitate these conditions with artificial light. It was found that either a dark or a very light background was necessary, the bevelling being viewed by diffused light against the background, but that the source of illumination should not have a high brilliancy-say, not more than to 1 c. per square inch. A small experimental unit was, therefore, made up, consisting of a rectangular box about 24 ins. by 12ins. (face) by 6 ins. deep, the front being of translucent glass bordered by a broad wooden frame. One or more 60-watt Tungsten Filament Lamps were placed in the box to illuminate the translucent window to about c. per square inch or less. The bevel could be viewed either against this bright translucent window, or against the dark border surrounding it. One 60-watt lamp appeared to be enough to illuminate a surface 1 ft. 6 ins. by 8 ins. süfficiently to enable the fine markings left by the grinding to be seen with ease. Some general lighting was also provided from the lower part of this unit, either by a reflector or by simply leaving the case open at the bottom. Although this apparatus was actually used with electric light, an exactly similar system could be used with incandescent gas lighting. We are indebted to Messrs. Sandwell & Sons for facilities for the trial under actual working conditions of the apparatus described. I'rinted under the Authority of HIS MAJESTY'S STATIONERY ()FFICE By HARRISON AND SONS; LTD., St. Martin's Lane, London, W.C. 2. ANNUAL REPORT OF THE FISHERY BOARD FOR SCOTLAND Being for the Year 1921. Presented to Parliament by Command of His Majesty. EDINBURGH: PUBLISHED BY HIS MAJESTY'S STATIONERY OFFICE. To be purchased through any Bookseller or directly from IMPERIAL HOUSE, KINGSWAY, LONDON, W.C.2, and 28, ABINGDON STREET, LONDON, S.W.1; 37, PETER STREET, MANCHESTER; 1, ST. ANDREW'S CRESCENT, CARDIFF ; or from EASON & SON, LTD., 40 AND 41, LOWER SACKVILLE STREET, DUBLIN. 1922. Price 8s. Net. [Cmd. 1675.] |