656 BOARD OF AGRICULTURE. 



The above-described samples of salt have been offered of 

 late in our markets as " dairy salt," judging from communi- 

 cations received. As the recent introduction into our mar- 

 kets of various brands of salt from new salt works in western 

 New York imparts a particular interest to the question of 

 what constitutes a good dairy salt, a short discussion of that 

 question may not be without interest in connection with the 

 above analyses. 



There are three sources of supplj^ for the manufacture of 

 salt ; namely, sea water, brines and rock salts. None of 

 them yield by any current mode of manufacture a chemically 

 pure article of sodium chloride ; all three may be success- 

 fully turned to account for the manufacture of the various 

 brands of salt in our market. 



Local circumstances control the selection of the particular 

 source of supply ; and, as the particular fitness of salt for 

 different domestic applications, as meat-packing, family use 

 and dairy, depends not only on a fairly good chemical com- 

 position, but also to a considerable degree on a suitable 

 mechanical condition, it is quite obvious that the selection of 

 the mode of manufacture has to be made with reference to 

 the general character and the quality of the source on hand, 

 and to the kind of salt desired. 



Our home-manufactured salt — "coarse," "fine" and 

 " dairy salt" — has been produced, until of late, almost en- 

 tirely from natural brines, sea-water excluded. All natural 

 brines contain more or less of foreign saline admixtures. 

 Most prominent among these are the sulphates of lime and 

 magnesia, and the chlorides of calcium and magnesium. 



The general character and the industrial value of different 

 brines, considering concentration equally favorable, depend 

 as a rule not so much on the total amount of foreign saline 

 substances present, as on the relative proportion of the above- 

 stated foreign admixtures. 



The same circumstances apply with equal force to the salt 

 produced. The less chlorides of calcium and magnesium a 

 salt contains, the better will be considered its quality, from a 

 commercial stand-point. The presence of sulphate of lime, 

 within certain limits, is far less objectionable. 



A salt which contains but one-fourth of one per cent, of 



