184 GUANO. 



manures none operate so speedily or can be so con- 

 veniently put on to the land. Old compost earth, 

 when sprinkled frequently with urine, would approx- 

 imate most closely to the action of guano. 



As good guano consists of thoroughly 3ecayed 

 excrements, in which the manuring constituents, 

 both the combustible or organic and the incombus- 

 tible or mineral, are all simultaneously present, it 

 can be just as properly applied alone as rotten 

 muck ; indeed, it will have decided advantages over 

 the latter in all cases where a brisk and vigorous 

 action is required. 



Its employment is of the highest benefit to oil- 

 hearing' plants of all kinds, — to rape, beet-root, 

 rocket, etc., — as also to potatoes ; next to these, to 

 wheat and rye ; then to barley^ tares^ and pease ; and 

 finally to oats. The scale of diminishing utility 

 here intimated is, however, in no respect so great, as 

 to render the application of guano to the crops last 

 mentioned otherwise than extremely advantageous.* 



* The oil-bearing plants alluded to here are : — 



1st. The Rape, Brassica napus, var. oleifera, Dec. ; this is the more 

 commonly cultivated on the continent of Europe, and particularly in 

 the eastern parts of France, where it is called Colza. It requires a 

 rich, moist soil, and will grow well on the sea-coast in marshy spots ; 

 this is the Raps of the German. 



2d. Brassica prcpcox J or Summer Rhipe. This, as its name indicates, 

 is an early variety, and is harvested in June; the land is then ready for 

 a second crop of some other vegetation. It will grow well on up- 

 lands and in mountainous districts, and is the variety alluded to 

 above, of which the cultivation has been so much extended by the 



