in Denmark, Sweden, and Russia. 409 



This happy expectation was founded on the introduction of the 

 new manure guano, Avhich was to be carried along the line in 

 such quantities as, besides remunerating the shareholders, to con- 

 vert also the barren heaths and moors of Central Holstein into 

 blooming and productive fields. 



Though much corn and rape are grown in the country around 

 Kiel, yet I believe butter is one of the principal articles of export. 

 On some of the farms 200 or 300 cattle are kept, yet on the 

 whole route between Hamburg and Kiel I did not observe a 

 single field-turnip. In Holstein much of the soil is said to be 

 now tired of rape. The cultivator of the land in almost every 

 country is under a strong temptation to raise crop after crop of 

 that kind of produce which finds the readiest sale and yields the 

 largest return. In Great Britain we grow corn as often as we can, 

 and Holstein exhausts herself to supply us with rapeseed, Jamaica 

 to send us sugar, and the United States to give us cotton, tobacco, 

 and rice. 



There is a remarkable chemical difference between the straw of 

 the corn-bearing plants and that of rape — the former containing 

 much silica, the latter much potash, soda, and lime.* It is pos- 

 sible, therefore, that a saline manure might ameliorate the soil on 

 which rape has ceased to thrive. Rape -straw spread upon the 

 fields and burned, is known greatly to promote the growth of the 

 succeeding crop. A properly adjusted mixture of the saline 

 substance of which the rape-ash consists would form a rape 

 manure, from which similar advantages might be anticipated. Even 

 where husbandry is most carefully practised, and as much as 

 possible of all the produce is again returned to the corn-fields, 

 there is always an annual loss of the saline constituents of the soil 

 and crops, carried away chiefly by the rains and. drains, which 

 must in some way or other be restored to the land, or it will ulti- 

 mately deteriorate in quality. A rational practice, therefore, as 

 well as sound, theory, indicates the trial, after previous marling, 

 of a mixture of common salt with sulphate of soda, wood-ashes, 



* Thus 1000 lbs. of ripe wheat and rape straws, though they left respectively 

 nearly the same weight of ash when burned, yet contained the several con- 

 stituents of the ash in the following very different proportions : — 



Potash 



Soda 



Lime 



Magnesia 



Alumina and oxide of iron 



Silica . 



Sulphuric acid . 



Phosphoric acid 



Chlorine 



VOL. TIT. 



