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

22 SEA WATER DISTILLATION. that on the surface, in the tropics, the sea water being more subject to evaporation, would make it salter. Ocean water may, therefore, be accepted as containing 3'5 per cent, of saline matter, of which about 3 per cent, consists of chlorides. 11. All the above analyses show the great preponder- ance of chlorides and sulphates, especially the former, in the shape of common salt. Table B also shows that the percentage of saline matter in sea water is about 3’6 per cent., of which chlorides constitute about 3-25 per cent. Note.—The specific gravity of the actual salt in sea water may be taken at 2'24. The specific gravity of sea water (containing, say, ;j\ of saline matter) would be 1*031. A saturated solution of salt and water will, when cold, hold about 36 per cent, of salt and, when at boiling point (226° F.), about 40 per cent, of salt. This equals a salinity ranging from about ?.1 to ?. H and a specific gravity of 1'32 to 1’35. See also Table C on p. 26. Salinometer Test. 12. When it is intended to ascertain the strength of sea water, or of brine, with the use of the salinometer, it is usual to deal with a specimen at a temperature of 200° F., * but as water expands by being heated, it is obvious that a cubic foot of sea water at 60° will weigh more, as it is denser, than a cubic foot of water at 200°, and this has to be allowed for when taking the record of the salinometer, as hereafter explained. A short Table (CC) on p. 2ö gives the weight of water at various temperatures, ranging from 40° (the tem- * Unless otherwise indicated, temperature is always expressed in Fahrenheit degrees in this work.