THE PHOSPHATIC MARLS. 115 



cost; i. e., into fertilizers which contain ten to fifteen per cent, 

 sohible phosphate of lime — all that is really necessary. Such 

 fertilizers ought to sell readily at forty dollars a ton, which 

 would yield a fine profit. After treatment with acid the fer- 

 tilizers dry readily, in spite of the small percentage of iron, 

 which, it was predicted, would interfere with the drying. 

 Patents have been given for treating the phosphates, when 

 hot, with brine and the liquor obtained from gas-works, to 

 which sulphuric acid has been added. The reactions which 

 take place when the phosphate has been heated, and when 

 treated with concentrated brine, have not been fully studied ; 

 but it appears as if the phosphate of lime and the silica were 

 put in a form where they can be more easily seized hold of by 

 the plant. 



" Such fertilizers, containing such large quantities of phosphate 

 of lime, and other lime salts, must prove of great value to our 

 agriculture, and, if ammoniacal matter be added, will be just 

 what the planter of the South and the farmer of the North 

 needs. At some future day the immense deposits of phosphatic 

 marl of the great South Carolina marl-beds will be used for 

 agricultural purposes. This contains, on an average, ten per 

 cent, of phosphate of lime, and when roasted would prove of 

 great value as a fertilizer for farms which need lime. At present 

 there must be at least half a dozen companies in Charleston 

 which propose mining these phosphates. Some have abundant 

 means ; others hardly anything beyond a name, officers and 

 lands. Many of the Northern manufacturers of fertilizers have 

 bought land, or made contracts for the raw material. As yet 

 but little is manufactured on the spot, the larger portion being 

 sent to the North for manipulation. 



" Fertilizers which have been made of this material have been 

 successful this season, as I hear by letter." 



This paper has just been received, and this is an entirely new 

 thing. It is proposed to obtain samples of this material in the 

 raw state, and also roasted and ground, and make some experi- 

 ments with it upon the college farm ; and, moreover, to prepare 

 with acids, and in other ways, specimens of the phosphatic rock, 

 and experiment with them. As we are to have a gentleman to 

 take charge of this subject of agricultural chemistry, in the 



