226 BOARD OF AGRICULTURE. 



GERMAN POTASH SALTS, 



About 1850 an effort was made to open a salt mine at Stassfart 

 in Saxony. Salt was reached in 1857 at a depth of over one thous- 

 and feet In sinking the shaft beds of potash and magnesia salts 

 were passed through; in 1861 a factory was established to purify 

 these salts and put them in commercial form. The first ot these 

 crude chemicals were brought to the United States in 1868. There 

 are several forms of these salts, the muriate, sulphate, also what is 

 called kainit, krugit, etc. 



NITROGEN. 



Nitrogen is a costly element of plant food, its use should be well 

 looked to, when we remember that every pound of nitrogen will 

 cost us not far from twent}- cents, while a pound of phosphoric acid 

 (PjOj) costs less than eight, and of potash (K^O) about five 

 cents, it is evident that we cannot afford to be so thoughtless about 

 the nitrogen as we often are about the other two. 



As has been already' said, nitrate of potash was one of the earliest 

 fertilizers used ; it contains about thirteen per cent, of actual nitro- 

 gen. The high value of nitrate of potash as a constituent in the 

 manufacture of gunpowder, prevents the use of this source of nitro- 

 gen in agriculture, but about 1820 a substitute was found in the so- 

 called Chili saltpetre, or nitrate of soda. This source of nitrogen 

 was not at first popular ; the first ship load, going begging for a 

 customer in P!ingland, was sent off to this country. At present, 

 however. Chili Saltpetre is regarded as a valuable source of nitro- 

 gen. It is dug from the ground in South America, where it has 

 accumulated in pas<^ ages. 



In 1836 "Gas Liquor" was first used in England. This is 

 the water in which illuminating gas is washed, and is found to 

 contain ammonia gas (commonly called hartshorn) ; ammonia gas is 

 made up of nitrogen and hydrogen, fourteen parts of the former to 

 three parts of the latter. The results from the use of this liquor com- 

 pared favorably with those from saltpetre, but the bulk was too great. 

 Later, by the use of sulphuric acid the ammonia gas was saved in 

 the form of sulphate of Ammonia, which to-day forms one of the 

 best sources of nitrogen. 



English farmers long ago learned the value of dried blood, and 

 for a time English speculators bought both dried blood and bones in 

 this country and shipped them to be used on English fields, but as 



