ACTION OF GYPSUM ON CLOVEK. 321 



Pincus, of Insterburg, are the most important, both, on 

 account of the careful manner in which they were con- 

 ducted, and the conclusions drawn from them. At Dr. 

 Pincus' request, three plots of ground, each of a morgen 

 (about f of. an acre) in extent, and lying close together, 

 were selected by Mr. Eosenfeld in the beginning of 

 May, from the middle of a large clover Held in the 

 neighbourhood of Lenkeningken. The clover crop had 

 a very promising appearance, and the plants were then 

 about an inch high. One of the plots was manured 

 with a cwt. of gypsum, the second with the same quan- 

 tity of sulphate of magnesia, and the intervening plant 

 was left unmanured. The clover field from which the 

 plots were selected was one of the best cultivated and 

 most fertile in the district, and had produced in the 

 preceding summer an abundant rye crop. The plants 

 growing on the unmanured plot, when compared with 

 those on the manured, very speedily presented a differ- 

 ence of colour and condition. 



On the plot manured with gypsum, they were of a 

 deeper green, and stood higher. The difference was 

 most striking at the time of flowering, which occurred 

 in the unmanured plots four or five days earlier than 

 in the manured ; the whole field being everywhere in 

 full bloom, when scarcely a flower was to be seen in 

 the manured plots. When the manured plots also were 



Antweiler, Aldenau district (volcanic Eifel mountains), sowed a plot of 

 land, said to abound in broken shells, with esparsette. For ten years he 

 obtained good hay crops, and abundant after-grass. After this time a good 

 deal of grass began to make its appearance among the esparsette. To 

 destroy this Mr. Kirfield had his field deeply harrowed in spring, with iron 

 harrows across the ridges, and then sown over again with 8 pounds of red 

 clover seed. The red clover grew up splendidly with the esparsette, and 

 gave for three years running two full crops per annum. At the end of the 

 third year the land was again deeply harrowed and sown anew with 8 

 pounds of red clover seed. It gave again for three years running two full 

 crops per annum of an excellent mixture of esparsette and red clover. 

 The same operation was repeated twice after with the same success, so 

 that the field has now for twenty-two years, consecutively, borne clover ; 

 that is to say, the first ten years esparsette alone, the following twelve 

 years esparsette with red clover.' 



It would be interesting to get a proper analysis of this soil, with especial 

 regard to its absorptive power for potash and phosphate of lime. 

 14* 



