852 Transactions of the American Institute. 



moiilj unknown to tlie tillers of the soil, and to mold it into shape, 

 supply its deficiencies by research into its detail, and apply it to the 

 purposes of every-day life, common sense tillage, profitable farming. 

 We cannot, in these days, learn much more than we know of the 

 constituents of plants or the evil results of the absence of any one of 

 them, for this subject was sifted some decades of years ago by Salm 

 Ilorstmar, who found, for instance, that, although a plant might 

 vegetate without silica, it would not haye strength enough to stand 

 up alone ; that without lime it would die before producing its second 

 leaf; that without potash and soda it would scarcely grow at all ; 

 that magnesia is necessary to its strength ; and that without sulphu- 

 ric acid it will produce no fruit. "We cannot hope to add much to 

 our knowledge of how water passes repeatedly through the structure 

 of a plant, so that the quantity exhaled from it is often greater than 

 the total rain-fall on the ground whereon it grew, inasmuch as Saus- 

 sure found out all that seventy years ago. Pretty much all has been 

 learned that can be learned of how ammonia passes into the roots in 

 solution in water, and carbonic acid into the leaves in its gaseous 

 form ; and for this we have to thank such men as Boussingault and 

 Liebig, who are old now, but who taught these things ere the flush 

 of their young manhood was past. Neither can we discover again 

 the doctrine of progressed manures, for that was set forth in this 

 room from the lips of the eminent Professor James J. Mapes, in days 

 when some of the younger members of this Club were boys, busy in 

 the practical avocations of the farm. 



As we have previously intimated, the opportunity for discoveries 

 of this character is for the most part over. They constituted, as it 

 were, the plowing of the great field of scientific agriculture, and the 

 laborers who come after must be content to harrow and hoe the 

 ground thus prepared, to plant therein the seed of patient and often 

 humble research, and to gain in due time the rewards arising from 

 practical utility rather than the triumphs of purely scientific progress. 

 The agricultural chemist who schemes to make his mark, or to bene- 

 fit the world by making some high-sounding discovery, may have a 

 weary time to wait. But he who seeks to put to the best uses what 

 has already been found out ; who tries to learn and to make the true 

 application of facts and principles already known, and who strives to 

 supply the deficiencies of great systems or discoveries hitherto made 

 by working out their practical details, will achieve a true and perma- 

 nent success, lie may miss the eclat that halos the numes of the earlier 



