1846.] Art and Science of Agriculture. 149 



metria, 1760), but is commonly attributed to Count Rumford, by 

 whom it was proposed in the Phil. Trans., vol Ixxxiv. The ap- 

 paratus required is extremely simple, consisting merely of a smooth 

 perpendicular surface of uniform color, and a rod for throwing the 

 shadow. Two lights which are to be compared are so placed 

 that, when the rod is interposed between them and the screen, the 

 two shadows maybe contiguous; and, so long as the shadows are 

 of unequal depth, one of the lights must be advanced toward, or 

 retired from, the screen, until an equality in depth is procured. 

 Suppose a wax candle at the distance of two feet, and a gas jet, 

 at the distance of two feet six inches, to produce equal shadows, 

 then, according to the above rule, the relative intensity of the 

 lights is as 4 to 6.25, or as 1 to 1.5625. — ParneWs Applied 

 Chemistry. 



AGRICULTURE AS AN ART, AND AS A SCIENCE. 



[Communicated for the Western Reserve Magazine of Agriculture and Hor- 

 ticulture, by Professor Jaeed B. Kirtland, M. D.] 



The history of agriculture as a science is brief. It can date 

 back to no early times — the ancients knew nothing of it, and at 

 the present day it is only partially understood. Every succeeding 

 day is developing some principle not before known, and the 

 practical application of others, hitherto understood only in theory. 



It is scarcely a generation since Chaptal and Davy wrote upon 

 this science, and, though learned as they were, it is now evident 

 that they hardly entered on the threshold of the subject. 



For its late rapid advancement we are principally indebted to 

 modern chemistry, though it has been essentially aided in its pro- 

 gress by the discoveries that have been made in several branches 

 of natural science, particularly botany and entomology. 



The distinction between the art and the science of agriculture 

 is strikingly manifested by the course each would take in investi- 

 gating the qualities of the soil. 



Art employs only one sense, that of sight. In such a course of 

 investigation, if the soil be black and mucky, as she technically 

 calls it, the conclusion is hastily drawn that it is rich and strono- — 

 if lighter colored, yellow, brown or red, that it has less streno-th. 

 Such conclusions are guess-work after all, and trials at cultivation 

 often prove them to be erroneous. 



Science proceeds systematically in such an undertaking. She 

 analyzes the soil, and ascertains the exact proportion of each 

 principle it contains. The result is certain. There is no guess- 

 ing in the matter. 



