A Practical Manual On Sea Water Distillation
With A Description Of The Necessary Machinery For The Process

184 SEA WATER DISTILLATION. the 24'4 tons (in the same time) ; but the proportion of primary and secondary water would then be— 13’6 primary water (from T36 tons of coal). 10'8 secondary water (80 per cent.). 24'4 total, in a given time. Instead of, as in treble distillation— 10'0 primary water ('from 1 ton of coal). 8'0 secondary water (80 per cent.). 6'4 tertiary water (80 per cent, of 8). 24'4 total, in same time. Note.—This is perhaps as good a way of demonstrating the difference between production in point of time, and production in point of economy, as can be given. Thus, in point of time, the total production (whether by double or treble distillation) is 24-4 tons, and this may be the work of, say, ten hours, so that in 100 hours the total production would obviously be 244 tons of water; but in point of economy, the production of every 24'4 tons of water would, in double distillation, be obtained by the consumption of 1’36 tons of coal, whilst in treble dis- tillation every 24'4 tons of water would be obtained by the consumption of only 1 ton of coal, no matter whether the time during the apparatus is at work is 10 hours or 100 hours, or 1,000 hours. The rate of water production per ton of coal would be the same irrespective of time, and in, say, a 1,000 hours' working, whatever weight of water is actually recorded, the weight of coal consumed would (in double distillation) be in the ratio of 24'4 to 1’36, which equals 18 of water to 1 of coal, whilst in treble