MARL. 



113 



There are in this country some substances used 

 largely as manure, and called marls, that have very 

 little lime in them. These are in certain parts of 

 New Jersey. The lime, in shells scattered through 

 them, varies from 10 to 20 per cent in some speci- 

 mens, in others there is scarcely any at all. The effect 

 of th s is, however, great dpon poor soils, and 



in N y they are verj- largely appliwi. The 



secret of their value lies chiefly in from 12 to 20 per 

 cent of potash, which the l)est of them contain, ac- 

 cording to the analyses of Prof H. D. Rodgers. 



It is always easy to ascertain whether any substance 

 supposcfl to he a marl, really is so or not, by trying it 

 with a littU'i lid. If there is much carlnmate 



of lime, the . iice will be strong and violent, 



owing to the bubbling up and escape of carbonic acid 

 gas. Carlwnate of magnesia and many other car- 

 bonates would, it is true, produce a like appearance; 

 but these are rnrelv found native, in very larcre quan- 

 tities. 



On some sections of the s.;i-ii.;iv,t, a s, shell 



or roral sand is to W ohtnii!' il. maiii i.; 's or 



V the act I 

 rr. On • 

 ot 1 



»«•'■ ,'■■■■ .' -•- - 



remains, which a<ld ni ■> its value. This, like 



the marls, may be sat« i\ ..un. d to the land in large 

 quantitit>s, without fear of injury to crops. 



10* 



