2GO ANNUAL OF SCIENTIFIC DISCOVERT. 



He believes that among the landed proprietors, their agents, and the larger 

 farmers, especially the rising generation, a more extensive knowledge of the 

 sciences applicable to agriculture is needed. All these want better instruc- 

 tion. But to teach the small farmer or the laborer chemistry, is simply 

 absurd. To cither, the pursuit would be waste of time. So chemistry should 

 never be made the direct guide to the agriculturist. Science is, after all, 

 only the systematic arrangement of well-authenticated facts, and the rising 

 generation should be taught its general principles. But many professors of 

 chemistry have over-estimated their own powers, and instead of explaining 

 the experience of practical men, they set themselves up as guides to the 

 farmers; they have over-estimated the powers of the new science, and in 

 consequence stumbled. Again he says: "Agricultural chemistry, in its ap- 

 plication to farming, is altogether a new science; and hitherto it has been 

 like every new knowledge, too vague and too general in its doctrines, as 

 well as in its researches. What is required at the time are, experiments 

 made for a special purpose, researches carried on in the field as well as in 

 the laboratory. We have no need of the joint labors of practical men and 

 men of science. There are questions which can only be properly investi- 

 gated if the man of science heartily joins with the practical man, working 

 cheerfully together, each in his own department, a nearer approach be- 

 tween agriculture and science, in short, is what is required at the present 

 time. A general knowledge of the principles of farming, however useful 

 to the practical farmer, never will help him to grow a large crop of turnips; 

 he must have special training in practical matters in order to be a succes.-ful 

 farmer. So it is with chemical knowledge. Men may have excellent general 

 chemical knowledge, but if they have not special chemical knowledge in rela- 

 tion to farming, their labors will be of little direct utility to the agriculturist." 



In reference to the cultui-e of root-crops, he says that, generally, ammoni- 

 acal manures, such as guano, are thrown away on roots; and phosphates 

 are more profitable. Guano and super-phosphate of lime both rather re- 

 tard the germination of the seeds, but they push forward the young plant 

 in its early growth. This we believe to form the true value of such manures, 

 though perhaps this is over-estimated. 



SUBSTANCES EXTRACTED FROM ARABLE LAND BY RAIN-WATER. 



Dr. Fraas, of Munich, has some time been making experiments to ascer- 

 tain the nature and quantity of the constituents of soils that are removed by 

 rain-water within a given time. The instrument used by him for this pur- 

 pose is called a lysimeter, and the substances obtained have been analyzed by 

 Hr. Zoeller. They were separated from rain-water that penetrated a square 

 foot of earth, six inches deep, during the summer of 1857, from April to 

 October. Five different extracts were analyzed: 



No. 1, from cultivated and manured calcareous soil. 



Xo. 2, from cultivated and unmanured clay soil. 



Xo. 3, from uncultivated and unmanured clay soil. 



No. 4, from uncultivated and manured clay soil. 



Xo. 5, from cultivated and manured clay soil. 



The manure applied to Xos. 1, 4, and o, consisted, in each instance, of one 

 pound of cattle manure without straw. 



The residues left by evaporation were yellowish or blackish-brown, and 

 very hygroscopic. They all contained the same constituents, with the ex- 



