MANURES. 267 



'' tain a few per cent, of lime-carbonate (clay-marls) are friable 

 *' and unplastic, and a copious dressing of lime upon a clay field 

 " converts it, after a year or two, into a marl with a highly im- 

 " proved texture." 



I have found in my own practice, in the cultivation of heavy 

 moist land in garden vegetables, that an application of a single 

 barrel of air-slacked lime per acre, spread with perfect uniformity 

 by a broadcast sower, resulted in a growth of cabbages and root 

 crops which I think it would have been impossible for me to 

 have attained on such soil without it. 



As an incidental advantage of the use of lime, I am led by my 

 own experience to indorse most fully the opinion of Peter Hen- 

 derson concerning its effect on certain insects which are especially 

 injurious to vegetation. He claims that the reason why those few 

 favored market-gardeners who cultivate a little tract on the shores 

 of Communipaw Bay are able to grow cabbages year after year, 

 on the same land, is, that this region was used for ages, in the olden 

 time, as a clam-baking ground by the Indians of New Jersey, and 

 that the immense number of clam-shells that are found to the 

 depth of a foot or more in all of the land of that region, exert an 

 influence on the soil which renders it unfavorable to the " club- 

 foot " insect. That this effect exists there is no doubt, although 

 it is not in accordance with our generally-received ideas to sup- 

 pose that bits of insoluble shells should produce a result at all 

 similar to that of caustic or even more crumbling carbonate of 

 lime. 



The practice of ages has shown that, both by increasing the 

 power of the soil to admit of the filtration of water and by render- 

 ing more available its hidden stores of plant food, an application 

 of lime to heavy land is productive of the very best immediate 

 results ; and in this case, as in that of Peruvian guano, the applica- 

 tion must be made with care and judgment. It is an old saying 

 among farmers of certain districts in this country that " lime kills 

 the land ;" and there is a very old couplet current in England, 

 which runs as follows : — 



