254 HANDY-BOOK OF HUSBANDRY. 



Sulphuric acid 06 



Phosphoric acid i -^ 



Water 80 



Carbonic acid, etc g-g 



lOO'OO 



This is an average of three analyses copied from Professor 

 George H. Cook's report of the geology of New Jersey. Ac- 

 cording to this estimate, one ton (2,000 lbs.) of green sand 

 marl contains — 



Lime io6 lbs. 



Magnesia 32 " 



Potash 96 " 



Soluble silicic acid 648 " 



Sulphuric acid 12 " 



Phosphoric acid 26 " 



(Equal to phosphate of lime, 56^ lbs.) 



It will be seen by this analysis that the amount of phosphoric 

 acid contained is sufficient to add very much to the effect of the 

 marl, but its content of potash is so great as to account for its 

 chief value, and all regions which are within reach of the marl- 

 beds, even by the aid of a cheap water carriage, may be greatly 

 benefited by the use of the material, which is found in comparatively 

 inexhaustible supply. It is to be recommended, however, that its 

 first introduction be only in an experimental way, as it is not equally 

 efficient on all soils. As a source of potash anywhere along the 

 Atlantic coast, it will probably be found an economical fertilizer. 

 In the fall of 1867, I purchased a cargo of about 140 tons of marl, 

 which cost, delivered on the wharf at Newport, $3.60 a ton; and 

 used it in various ways in my market-garden and at Ogden Farm. 



In the garden its effect was, in every case, very decided, espe- 

 cially on one tract of three-quarters of an acre of Jersey Wakefield 

 cabbage. The land was manured very heavily, of course, with 

 stable manure, but no more so than is customary in garden culti- 

 vation — no more heavily than my cabbage fields had previously 

 been manured. After the plants had been set out, a single handful 

 of a compost of equal parts of green sand marl and clear horse 



