372 BULLETIN OF THE BUSSEY INSTITUTION. 
tion), in his reports as Geologist of New Jersey and as Secretary 
of the New Jersey State Board of Agriculture. It is borne out 
furthermore by what is known of the use of palagonite and other 
forms of volcanic tufa in several localities. The green sand of 
New Jersey is said to be specially remarkable because of the per- 
manent improvement produced on many of the soils to which it has 
been applied. Mayer argues moreover that in certain cases, es- 
pecially when sandy soils are subjected to high culture, humus rich 
in potash is clearly indicated as a proper fertilizer — a conclusion 
which had been reached, in some part, by many New England far- 
mers of an earlier generation, as evidenced by the estimation in 
which they held ashes-compost as an application for light, leachy 
loams. He is inclined, indeed, to believe that the potassic manures 
of the future may perhaps be restricted to silicates, humate, and 
nitrate. But it is plain that this view does not duly allow for 
varying conditions as to soils and situations, and that by hold- 
ing too strongly to it a variety of useful powers and purposes 
which appertain to the carbonate, the chloride, and the sulphate 
of potash might be lost sight of; namely, their capacity to enliven 
the nitrogen of humus, to bind light loams, to improve the tilth of 
clays, and to feed leguminous plants, — as well as some kinds of 
hoed crops on poor lands. With regard to the point last named, 
Mayer commends Heiden’s plan of applying potassic fertilizers in- 
directly ; the idea being simply to use crude Stassfurt salts on 
pastures, or to apply them to clover, and to regard the dung of the 
cattle which have consumed the forage as a potassic manure spe- 
cially applicable to crops such as beets or potatoes which need 
potash, but which, for one reason or another, may not be able to 
bear the Stassfurt minerals as well as clover can. 
