CASKS CONTAINING HYDROGEN. 79 



contains about \ a P art m 10,000 ; the Schuylkill of Phila- 

 delphia, about 1 part in 10,000; the Croton, used in New 

 York city, 1 to \\ parts in 10,000. In the Schuylkill 

 water the constituents of the 1 part of solid ingredients were, 

 chlorid of sodium 1'47, chlorid of magnesium 0*094, sulphate 

 of magnesia 0*57, silica 0*8, carbonate of lime 18*72, car- 

 bonate of magnesia 3*51, carbonate of soda and loss 16*44.* 

 The water towards the surface is always purer than that 

 below. 



Sea water contains 32 to 37 parts of solid substances in 

 solution in 1000 parts of water. The largest amount in the 

 Atlantic, 36*6 parts, is found under the equator, away from the 

 land or the vicinity of fresh water streams ; and the smallest 

 in narrow straits, as Dover Straits where there are only 32*5 

 parts. In the Baltic and the Black Sea, the proportion is 

 only one -third that in the open ocean. Of the whole, one- 

 half to two-thirds is common salt (chlorid of sodium.) The 

 other ingredients are magnesian salts, (chlorid and sulphate,) 

 amounting to four-fifths of the remainder, with sulphate and 

 carbonate of lime, and traces of bromids, iodids, phosphates 

 and fluorids. The water of the British channel affords, water 

 964*7 parts in 1000, chlorid of sodium 27*1, chlorid of pot- 

 assium 0*8, chlorid of magnesium 3*7, sulphate of magnesia 

 2-30, sulphate of lime 1*4, carbonate of lime 0*03, with some 

 bromid of magnesium, and probably traces of iodids, fluorids 

 and phosphates. The bitter taste of sea water is owing to 

 the salts ofmagnesia present. 



The waters of theT)ead Sea contain 200 to 250 parts of 

 solid matter in 1000 parts, (or 20 to 25 percent.,) including 

 7 to 10 per cent, of common salt, the same proportion of 

 magnesian salts principally the chlorid, 2^ to 3^ per cent, 

 of carbonate and sulphate of lime, besides some bromids and 

 alumina. The density of these waters is owing to this large 

 proportion of saline ingredients. The brine springs of New 

 York and other states south and west, are well known 

 sources of salt, (see beyond under common salt.) Many of the 

 springs afford bromine, and large quantities of it are manufac- 

 tured for making daguerreotype plates and other purposes. 



What proportion of solid substances in sea water, and of this what 

 proportion is common salt '? What proportion magnesian salts ! What 

 s the bitter taste of sea water owing to ? 



t — . 



* Chem. Exam, by B. Silliman, Jr , Jour. Sci., ii ser., ii, 218. 



