98 PEACTICAL FARM CHEMISTRY. 



potash. The only thing that might come in consid- 

 eration here is the saltpetre waste of gunpowder 

 works, but this contains much more potash than 

 nitrogen. It analyzes about two per cent of nitro- 

 gen, and twenty per cent of potash, and is worth at 

 station prices almost $1.50 per 100 pounds or $30 

 per ton. 



In sulphate of ammonia we have a valuable by- 

 product of the gas works. It looks somewhat like 

 fine salt, and not being quite so ready to absorb 

 moisture and melt away, or to form large solid 

 chunks that have to be broken up, like 



Ammonia. .^ , « t . -, . 



nitrate oi soda, is much more convenient 

 to keep on hand, or to handle, or to mix with other 

 fertilizing substances. I have somtimes used it on 

 vegetables, and often thought it gave me just as 

 good results as the nitrate of soda. An average 

 sample contains twenty per cent of nitrogen, and 

 this is rated in the station schedules at eighteen and 

 one-half cents per pound, so that 400 pounds con- 

 tained in a ton make it worth $74.5(). Its nitrogen, 

 although not as readily available, is held by the soil, 

 and thus saved for plant growth, while any excess 

 of nitrogen in nitrates would at once try to make 

 good its escape down into the soil water and perhaps 

 into the drains, to be carried away to river or sea. 



Among other sources of nitrogen, cotton seed and 

 cotton -seed meal are probably in the front rank, es- 

 pecially as these substances are accessi- 

 ^Mealetc^ ble to farmers in many localities where 

 nitrate of soda, sulphate of ammonia 

 and similar nitrogen compounds are either not 

 readily obtainable or too costly in consequence of 

 exorbitant transportation charges. I admit that the 

 nitrogen in cotton- seed meal is not quite as readily 



