44- Journal of AgricuUurc . [ii July. 1910. 



Experiments on Open Dam Water. — A small water hole, containing an 

 estimated 1,000 gallons of a thick and dirty muddy water, situated on 

 the property of Mr. Ross, of Deep Creek, Templestowe, was treated on 

 the evening of 2nd May. with i Ih. of iron chloride. The concentrated 

 iron chloride solution was diluted, and just thrown out over the surface 

 of the pond, keeping the distribution as uniform as possible. The water 

 was not stirred at all, though it would have been more advisable to have 

 stirred the surface layers, so as to insure a regular distribution of the 

 chemical. 



Next morning, 3rd May, the water was clean, and every leaf and 

 twig could be seen on the bottom of the tank. 



A second experiment with a water hole on the property of Mr. Neil- 

 son, Warrandyte, was equall\ successful. The water had a surface area 

 estimated at 400 square feet, and an average depth of 9 inches. Capacity, 

 1800-1900 gallons. At 4 p.m. on 7th Mav 2 lb. of iron chloride in 

 solution were thrown out as evenly as possible o\er the whole surface 

 of the dam. ^Vith a long pole the surface layers were then gently 

 stirred. 



The water was next seen at 9 p.m., when it was perfectly clean and 

 all the mud had settled out to the bottom. The bacterial results with 

 these waters were just as satisfactory as with the tank experiments. It 

 should, however, be borne in mind that in clearing an. .open water hole 

 n heavy rain may wash fresh mud m, and so undo all the good work 

 accomplished. 



CONCLUSION.S. 



The chemical precipitation of the mud in storage tank waters has not 

 been found to fail in a single instance, so that the method should be 

 of general utility, no matter what is the geological nature of the country 

 in which the water dam is situated. 



In a country like Australia, where a clean water supply is often not 

 to be had, the case for a general use of chemical precipitation methods 

 is a very strong one indeed. 



Alum and lime are widelv obtainable, but if arrangements can be made 

 for a cheap supply, it is chloride of iron that is most strongly recom- 

 mended. From what has already been said, it is apparent how easy and 

 how eminently practical is its use. 



If the water prior to treatment is from a doubtful .source, such as a 

 .storage dam to which cattle have access, then it is recommended that it 

 should be either filtered or boiled before bemg used as drinking water in 

 the house. But if the water dam is in an enclosure and kept free from 

 pollution by cattle, precipitation alone yields an excellent water. 



It may further be added that, if desired, the flocculent mud could 

 be separated by running the water through a centrifugal machine, after 

 the addition of the chemical. This treatment, however, is hardly likely to 

 be necessary, seeing that the precipitated mud will settle down through 

 7 feet of water in a single night by the ordinary force of gravity. 



It is especially thought that clean waters so obtained should be 

 valuable in butter factories and dairies, or for use in steam-engines. Also, 

 stock are the better for a supply of clean, rather than dirty water, and a 

 liberal .supply of clean water is often acceptable for domestic purposes. 



It is for those who use or would use clean water if they could, butter 

 factory managers, dairymen, stock-owners, and others, to give precipitation 

 methods a fair trial. 



