ENERGY AS A FACTOR IN AGRICULTURE. 87 



of them by placing pieces of marble or lithographic stone in a 

 dilute solution of chloride or sulphate of manganese. The hope 

 of success is all the more legitimate because carbonate of lime 

 has already permitted the imitation in this way of several natural 

 minerals, particularly of limonite, an iron mineral, and bauxite, 

 or the mineral of aluminum. But the experiment has not been 

 successful, and, instead of the desired black deposit, we get only 

 chocolate-brown flakes having no resemblance to the substance 

 of the dendrites. 



Seeking for the causes of this want of success, I have found, 

 by analysis, that the dendrites said to be of manganese contain 

 oxide of iron, in minute proportions it is true, but in proportions 

 that seem to be sufficient. And the addition of traces of ferric 

 salts to the solution of manganese salt has really determined the 

 deposit on the limestone surface of a perfectly black compound, 

 presenting in many cases the exact form of the dendrites of 

 Nature. I have in the museum specimens that leave no doubt 

 on the subject, the inferiority of which to the models which I 

 sought to copy is most probably due to the inferior slowness of 

 the process of producing them. Translated for The Popular Sci- 

 ence Monthly from La Nature. 



ENERGY AS A FACTOR IN AGRICULTURE.* 



By Dr. MANLY MILES. 



THE rapid development of science and its numerous applica- 

 tions in the industrial arts are leading to a general recogni- 

 tion of its importance as a factor in the material and intellectual 

 progress of the age. The aid of science is now invoked in every 

 department of human activity, and, judging from what has already 

 been accomplished, we can not perceive any indications of a limit 

 to its useful applications in the industries. 



While the general outlook encourages optimistic views in re- 

 gard to the present and prospective advantages that may be real- 

 ized from the applications of science, we should not overlook the 

 shadows involved in its progress, which seriously interfere with 

 its own advancement, and at the same time increase the difficulties 

 attending original investigations relating to many industrial prob- 

 lems. 



The scope and extended range of modern science, that necessi- 

 tate a subdivision of its lines of research into numerous branches, 



* An abstract of this paper was read at the Washington meeting of the American 

 Association of Science, and also before the Society for the Promotion of Agricultural 

 Science. 



