THE YAN YEAN RESERVOIR.

Evening Star, Volume VII, Issue 1988, 18 September 1869, Page 2

THE YAN YEAN RESERVOIR.

The Australasian, of September 4, contains the following account of inves* tigations into the purity of the Yan Yean water:— “ All sorts of nasty things having been said about the Yan Yean reser* voir of late, the Government analytical chemest has been requested to report upon the disparaged fluid. Mr Johnson accoi’dingly paid a visit to the great watertank, and took samples from the centre thereof, and from two of its tributaries, viz.. Bruce’s Ci'eek and the Plenty River. He also supplied himself with a gallon from the servicepipe at St. Kilda. The results of his analyses of these samples proved to him conclusively that the water supplied to the city of Melbourne is of more than average excellence, and that there is every prospect of its improving rather in coming years. One 'of the points contained in Mr Johnson’s excellent report will go far to dissipate the groundless alarm created by the statements which from time to time have appeared respecting the impurity of some of the feeders of the Yan Yean. He says : —“ My attention having been directed to a statement that much impurity, and occasionally a dead bullock or two, were allowed to find their way into, the feeders of the reservoir, to the detriment of the latter, I have thought it

desirable to make some sort of estimate of the amount of contamination that might be communicated by this means. In round numbers the lake , holds, when full, about six thousand million gallons. Taking an ordinary fair-sized bullock at 8001b, and supposing that he was entirely dissolved, bones and all, and mixed with the waters of the lake equally, the carcase would yield less than one grain of any organic matter to every 3,000 gallons, or less than the three-thousandth part of a grain to a gallon. To contaminate each gallon of the water to the extent of one grain of such impurity more than 3,000 such bullocks must be dissolved at once and added; and even if they wei'e, such is the extraordinary power of self-purification possessed by water when well exposed to weather that it is more than probable, in a very short time indeed, the whole would become removed by oxidation and decay, and completely disappear.” As there is slight probability of 3,000 dead bullocks contaminating the Yan Yean at the same moment, we think the alarmists may rest at peace.