16 TRANSACTIONS OF THE 



to cnjo}- tlic light of the higher departments of knowledge, under the 

 investigations of such apostles as Young and Tull, Saussurc and Sir 

 llum])hre_y Davy. At length the surprising growth of all the physical 

 sciences i'lirnished the materials out of which the lahorious genius of 

 Liebeg, in eighteen hundred and forty, constructed the benificent science 

 of agi'icultural chemistry — a science which is destined to rejuvenate and 

 glorify old art forever. Ilail and welcome to the new science of agri- 

 culture ! '' The mountains and the hills shall break forth into singing, and 

 all the trees of the field shall elap their hands. Instead of the thorn, 

 shall come up the fig tree, and instead of the brier shall come up the myr- 

 tle tree ; and it shall be to the Lord for a name — for an everlasting s^ign 

 that shall not be cut otf." 



Doubtless we have found ''great spoil !'' Yet it ill becomes wise men 

 to forget that, to our imperfect faculties, knowledge, in all departments, 

 is a measurable quantity. Much which passes for science consists of 

 " names given to our ignorance." We discover certain elements whose 

 combinations constitute growth, but the mode of their combinations 

 eludes our search. "Were we possessed of exact and suftlcient knowledge 

 as to the conditions and quantitative combinations of oxygen, hydrogen, 

 nitrogen, and carbon, in the air, and potash, soda, lime, magnesia, silica, 

 sulphur; phosphorus, and chlorine, in the earth, with all the geograph- 

 ical, meteorological, mechanical, and chemical conditions involved in the 

 growth of every variety of plant, and in the qualit}^ of every soil, then, 

 indeed, we could furnish j^lant-food with mathematical exactness. But 

 this is far from being true of the most gifted and learned, while to the 

 mass of cultivators the general results of scientific research are all that 

 can be successfLilIy conveyed to them. 



Consider the difficulties which embarrass the scientific cultivation of a 

 single field. The atmosphere supplies its own appropriate elements in 

 large excess. We may, therefore, confine our attention to the food 

 which the earth j-ields to plants through the solvent agenc}" of water, 

 assisted by carbonic acid and ammonia. The natural soil usually con- 

 tains, in variable quantities, "all the varieties of telluric plant-food. We 

 must ascertain which kinds are abundant, and which deficient. This 

 necessitates an analysis, which is expensive to begin with, and extremely 

 unreliable to end with. The soil of an acre, taken to a depth of one 

 foot, weighs, say three and a half millions. An average crop of small 

 grains removes three hundred and fiftj' pounds; a root crop, six hundred. 

 It will be seen that the quantity taken up as ash matter is extremely- 

 small compared with the entire mass. This minute amount includes all 

 the varieties of telluric food, mixed with a large preponderance of earthy 

 matter. These varieties may be very unequallj^ distributed over the 

 same field. The chemist takes five, or fift}'^, or five hundred pounds from 

 diff'creiit parts of the field. The qualit}' of the water employed in the 

 analysis will aflect the result. The quantity of rain which falls during 

 the season, the nearness of water to the surface, the proximity' of a close- 

 textured substratum, the mechanical condition of the soil as to fineness, 

 and coarseness, obduracy, and friability, the lay or slope of the field, and. 

 the presence of more or less of certain cognate chemical agents, will 

 modify the efficacy of the lacking ingredients which we are instructed 

 to su])ply. 



IIuw unsatisfactory such an analysis must prove, will appear to all 

 who are capable of reflection. At the same time, the general results of 

 agi'icultural chemistry are of incalculable benefit. lii addition to the 

 novel and ennobling interest with which scientific knowledge alleviates 



