USE OF SALT-REFUSE. 39 



engaged to manufacture a so-called concentrated dungsalt 

 by a process which aims at, if not the entire, at least, the 

 partial exclusion of the chloride of sodium (salt) from its 

 saline constituents. The fact that the price of the Stassfurth 

 dungsalt is controlled at present by its percentage of chloride 

 of potassium, and not by that of the salt (the chloride of so- 

 dium), illustrates almost as well as anything else the drift 

 of opinion.* 



I have stated already that many reports on experiments with 

 salt speak of it as refuse-salt, or salt-refuse, or refuse of salt works, 

 designations, which apply to substances of a quite different com- 

 position and value. These substances are obviously recommended 

 because a good salt is too expensive to be economical. Salt-refuse, 

 coming from our home salt works, may be obtained from three 

 different sources ; it may be an incidental result of the manu- 

 facture of salt — a salt of an inferior color ; it may be the 

 ground-up incrustations of the boiling kettles, or the dried-up 

 mother liquors. The first kind is most properly called refuse- 

 salt ; it consists mainly of salt (80-90 per cent.), with varying 

 quantities of sesquioxide of iron, caustic, carbonate and sul- 

 phate of lime ; it is frequently used for salting hay, and 

 entirely unfit for other domestic uses. The second article, from 

 our salt-boiling establishments east of the Mississippi River, 

 consists of salt and gypsum (plaster, sulphate of lime), varying 

 from 10-90 per cent, of the former and 90-10 per cent, of tlie 

 latter ; from the brines of Kansas and Nebraslia this article 

 would consist mainly of sulphate of soda, sulphate of magnesia 

 and sulphate of lime, which imparts a much higher value to it. 

 The third article, the dried-up mother liquors, would contain 

 large quantities of the chlorides of calcium and magnesium, 

 besides chloride of sodium and smaller percentages of chloride 



* Analysis of two Specimens of Stassfurth Dungsalt. 



I. II. 



Chloride of sodium, 84 56 



Chloride of potassium, 3 18 



Sulphate of potassa, ' . . 2 1 



Sulphate of soda, - 7 



Sulphate of lime, 1 5 



Carbonate of lime, - 2 



Coal and other organic substances, 7 2 



Water, 3 9 



