274 STATE BOATED OF AfmiCULTUIlE. 



It makes no difTcrencc how niiiny or how much of these foreign substances are 

 contained in salt — tlie more the better, lie would find good reasons why such 

 a combination of salts would be valuable for manure because it contains so 

 many substances "absolutely essential" to plant life, and all of them in a 

 soluble and available form. In other words, the poorer the salt the better the 

 manure. We thus see that the tedious and expensive processes in the manu- 

 facture of table salt for getting rid of these foreign materials is worse than 

 thrown away in making a salt for manure: the longstanding in the settling 

 vats for oxide of iron to se])arate and subside, the removal of sulphate of lime 

 during the boiling, the prolonged draining to get rid of chloride of calcium 

 and magnesium, all these can be dispensed with, and the brine may be boiled 

 down as soon as it is pumped, without any cleansing process, and yet furnish a 

 better salt for manure than the best dairy salt. One-half of one per cent of 

 oxide of iron would make the salt so rusty that we would reject it at once for 

 table use, but it would not diminish its value as manure, and the salts of lime 

 and magnesia enhance instead of destroying its value as manure. 



We analyzed some refuse salt from Bay City to determine its value as ma- 

 nure. It is so rusty that no one would dream of using it on his table, and if 

 it were used to salt beef or fish, the results would be disastrous, yet its value 

 for manure may be seen from the results of analysis: 



Common salt 87.74 



Chloride of potassium - 2.49 



Sulphate of lime — - - 1.68 



Carbonates of lime and magnesia .75 



Oxide of iron - 87 



Water - - - - 6.38 



99.91 



Salt that contains 2^ per cent of chloride of potassium in place of the same 

 amount of chloride of sodium, is worth $1.00 a ton more for manure than 

 pure salt. 



In the remarkable results that I have already quoted in your hearing, from 

 the use of salt as manure in New York and in Canada, it was the refuse salt 

 of the salt works that was used in nearly every instance. 



I trust the salt boilers of Saginaw valley will turn their attention to manu- 

 facturing a cheap agricultural salt, by boiling down the brine directly from 

 the pump, that the farmers of Michigan may have a chance to test its value 

 as manure. The use of salt in this State has received but little attention, while 

 plaster has come into almost universal use. Our climate, and much of our 

 soil seem to be well adapted to the use of salt as manure. I hope to see a new 

 departure both in the manufacture and use of salt in our State. 



Agkicultural College, Feb. 16, 1880. 



