Report of the Coloured Labour Compound Commission appointed to enquire into the cubic amount of air-space in the compounds of the mines of the Witwatersrand.

Date:: 1905

Credit: Report of the Coloured Labour Compound Commission appointed to enquire into the cubic amount of air-space in the compounds of the mines of the Witwatersrand. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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$Can you tell me what was the area of this opening through which 400 feet per minute were passing ; was that one of 15 in. square ?— Minutes of Kvideiice That IS an intake, but, unfortunately, I have not the original copies of these ^ , ° J. R. Wtlhams. analyses. Do you happen to know the size of these intakes ?—15 in. by 17 in., I think. We measured them and made them 16 by 15 ?—It would be very simple for me to give you an actual copy of these. We have got them all on the plans. Now as far as I can make out, during the next three hours they must have had some 2,340 cubic feet per head coming in there. That would reduce it down to '34, and then to reduce it from ‘34 to '13 you must have had something near 5,000 cubic feet coming in ?—Part of that would be accounted for by the various conditions of the fires. But there are no fires ?—But there are many other things. The boys may not have been smoking, or had no candles burning and so on. In nearly all cases you will observe that after one in the morning, the air in the compound was considerably purified, which was due, I think, to the reason that on the still nights when we were sampling, there was a gentle breeze which assisted ventilation, and also the fact that all the boys were asleep and not sitting round. I have seen as many as 10 boys sitting round the fire smoking. They would not be doing that between one and three a.m. ?—Up to 12, they would. In this particular case they were constant ?—Yes. As far as I can make out, there must have been somehow or other, 5,000 feet of air per head coming into that room. There must have been an enormous number of changes of air during the hour ?—:The size of the room was 8,200. Dr. Moir has suggested that, perhaps you took that particular measure- ment at the opening of the eaves or air-holes ?—In all these cases, the anemometer was only used on the air bricks and also on the louvres over the door. Yes ; you have given 400 feet per minute, and the outside air was moving at 580. I am not cavilling at that, but it strikes me there must have been a tremendous amount of change going on in that room at that time ?—Not so very great. The size of the room was 8,200 cubic feet. Yes ; with 35 boys in it ?—Now, as, at least, 60 per cent, of the volume of the room per hour is going through the hood over the stove, it does not mean a very large amount to go over the louvres afterwards. Still, the air must have mixed with it to have reduced the CO2. If it was short circuited, as in the one instance, then it did not affect the CO2 ?—What I mean to say is that after the figures you have given there is 48,000 feet accounted for going through the louvre, which is ]ust on a level between the two bunks, and, therefore, not causing the boys any inconvenience at all. I want you to come and look at my figures and see if they are correct. (Dr. Turner explained his calculations to Mr. Williams.) Referring to the amount of air-change mentioned by Dr. Turner, the witness said, judging from the general condition of the room and the absence of anything approaching to a draught, I should say it was quite impossible. That figure w^ould mean a hurricane blow- ing. That is why I cannot understand these figures. {The Chairman.) There must be an error somewhere ?—There can be no question at all about an error in the amount of CO2 in the room. That is absolutelv final They were carefully checked, and at least three samples were taken with regard to the purity of the air. I would certainly vouch that there was no draught at all in these rooms. {Dr. Turner.) How do you account for it ?—I must say I would like to check those figures. That is particularly why I asked you ?—All right, I shall do so. The difference may, possibly, be accounted for by the condition of the outside air. Then I am to disregard that figure altogether ?—No, Sir ; but I say the outside air only gives you a fair idea of the inside air. I have had the outside air as high as 7.$