2 Jan., 1908.] A Cheap Condenser . 39 



weighted so that it stands upright with the tube ahnost immersed when put 

 in pure water. Tlien salt may be added to the water in instalments at 

 tne rate of say i oz. per gallon until a limit of 15 oz. per gallon is reached. 

 As the salt is added and dissolved, the hydrometer will rise ; a mark 

 should be made on the tube at each point. If properly done, the hydro- 

 meter will show at a glance by the markings the amount of dissolved 

 solids m any sample of water into which it is placed. One gallon of 

 fresh water weighs exactly ten pounds. This is important as the operator 

 must be able to ascertain when the liquid in the boiler has become so 

 •concentrated as to have 15 ounces per gallon dissolved in it, as beyond 

 that density the salt or other solid matter will commence to deposit. The 

 following is an analysis of a tvpical brackish water from a well in the 

 Mallee:— 



Total solids per gallon ... 600 grains 



of which ... ... 473 grains are common salt. 



In this case, the amount of salt and solids present would be generally 

 considered too high for stock purposes, though it is quite possible sheep 

 would become accustomed to it. As there are 43 7 j grains in an ounce, 

 the sample quoted has about one and one-third ounces to the gallon, 

 consequently it may be concentrated about n times, or in other words, 

 II gallons of the saltwater should yield close upon 10 gallons of con- 

 densed water, leaving i gallon of concentrated 15-ounce liquid. If a 

 hydrometer were made as described, it would have shown in the stem, 

 approximately,, one and one-third ounces to the gallon in the above 

 sample. When the liquid shows nearly 15 ounces of solids to the gallon, 

 it should be run off and the boiler refilled, or a considerable portion taken 

 out and replaced by the original salt water. Attempts were* made to air 

 condense, dispensing with the water bath for the down pipes ; but it 

 proved a complete failure. Even on a cold night with strong winds, the 

 results were only about 3 gallons per hour though something like 30 were 

 being evaporated. 



Description of Condenser as illustrated. 



The condenser consists of a 400-gallon tank used as the boiler, set ©n 

 a brickwork foundation with a fire grate. The vapour fiom the boiling 

 water is conveyed from the top of the boiler by a bell-mouthed bend and 

 then through about 150 feet of 2|-inch down-pipe, which is laid in a box 

 kept filled with salt water. All joints of the piping must be made steam 

 and water tight. The vapour passing through them is condensed into 

 fresh water before reaching the end of the pipe projecting through the 

 side of the box and is caught in any suitable receptacle. The condenser 

 box is made from i^-inch T. and G. flooring boards. A brine cock is 

 fitted to the boiler to draw off the concentrated brine. A filler, which also 

 serves as a water gauge showing how much water is in the boiler, is fitted 

 to it with a pipe connexion. The materials for the above will cost about 

 ;^i5 in Melbourne. The plant will vield about 30 gallons of condensed 

 water per hour. 



A system for a continuous supply and on a somewhat larger scale may 

 be readily grasped from the following description. There is a windmill, 

 pump, and elevated storage tanks as well as a fresh- water tank. The 

 boiler is 8 feet long by 4 feet and may be either circular or square. It is 

 set in brickwork. The condenser box is as before; but is elevated and 

 has wrought-iron condensing pipes instead of the i8-gauge galvanized 



