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

I 2 SEA WATER DISTILLATION constant attention to the working and manipulation of the apparatus would entail expense and trouble that might be objected to for so small a supply of water. This type of apparatus will be referred to more in detail later on. Quality of Water Produced. 15. Before leaving the present general review of the purposes for which distilling machinery is used, it is well to say a few words regarding its purity, as there are grades of quality, some being good enough for one pur- pose, but not for others. Pure water means water that is absolutely pure, but a very small amount of saline matter may be carried over with the steam, by what is termed priming, so that distilled water, passable for drinking purposes—that is, not containing sufficient saline matter to condemn it for such use—might be considered very objectionable if the distilled water is required for, say, feeding water-tube boilers, or for use in connection with accumulators, where water of absolute purity is required. 16. The composition of sea water is more fully dealt with in the next chapter, but we must just anticipate matters slightly, for the purpose of dealing with the quality of the distilled water after its saline matter has been separated. This saline matter will be found to be, for the most part, chlorides generally, and particularly chloride of sodium, or common salt. Qualitative Analysis. Testing /or Saline Matter. 17. The test for chlorides is nitrate of silver, acidified with nitric acid. The chlorine attacks the silver, with