356 CHEMISTRY. , 



manures. From a deficiency of this knowledge mistakes 

 are made continually by farmers. For example, lime has 

 been often applied where there was already enough of it, 

 as might be shown by a chemical analysis of the soil, and 

 so has proved, not merely a waste, but a positive injury to 

 the land. A very simple test will often give valuable in- 

 formation. Suppose, for instance, we take a pound of earth, 

 and after boiling it for some time in about a pint of water, 

 so that the lumps may be all destroyed, and the earth uni- 

 formly diffused in the water, introduce into the mass a strip 

 of blue litmus paper. If this after a little time turns red 

 it shows that the soil is sour, and that the humic acid in it 

 requires the application of lime to neutralize it. Chem- 

 istry may be made use of often by the farmer in discover- 

 ing rich materials for fertilizing his land. Beds of marl 

 have been found here and there which have proved of 

 great value as furnishing a fertilizer for certain soils. We 

 will quote here some remarks of Stockhardt on these dis- 

 coveries : " Probably such treasure still lies hidden in the 

 ground in many other places ; it appears only to require 

 the divining-rod to indicate where it lies, and the touch- 

 stone by which it can be ascertained whether it really is 

 what it appears to be. Yet both are close at hand : the 

 divining-rod is called 'look for it,' and a wine-glass of 

 'hydrochloric acid' serves as a touch-stone. How many 

 accidental opportunities the farmer has of penetrating a 

 little deeper than usual into the earth ! Here a well is 

 dug, or a ditch ; there a hill is leveled or cut through in 

 road-making ; in other spots a stone-quarry, a sand or loam 

 pit, is opened. These are all excellent opportunities and 

 even deep -plowing' and ordinary work with the subsoil 

 plow not unfrequently furnish others to make acquaint- 

 ance with the kind of earth lying beneath the cultivated 

 Boil. If an earth of different character is met with under 



