SKETCH OF DR. J. W. DRAPER. 361 



central forces, but to trace the differentiation and transformation of 

 material forms as determined by the differentiation and transformation 

 of the formative energy of the universe. In this connection, observa- 

 tion and experiment have brought to light a number of the most sig- 

 nificant facts, to one of which I may be permitted to draw attention 

 before the conclusion of this paper. Force, or, more correctly speak- 

 ing, energy, is not only indestructible, like mass ; it not only passes 

 through a cycle of transformations corresponding to the metamorphic 

 round of physical forms ; it is not only specialized at even pace with 

 the specialization of its corresponding material structures ; but, just as 

 the progressive specialization of these material structures is, on the 

 whole, an advance in the direction of greater definiteness and more per- 

 fect concretion (in the case of inorganic bodies, generally accompanied 

 by greater condensation) : so, also, the specialization of formative ener- 

 gy is, on the whole, characterized by an ever-increasing intensification. 

 Generally speaking, the more advanced the stage of material concre- 

 tion, the greater the intensity of its constitutive force. Faraday has 

 somewhere observed that the chemical force contained in a drop of 

 water, if transformed into heat and light, would be sufficient to illu- 

 minate the heavens. Of course, this intensification of force, in propor- 

 tion to the condensation, concretion, and differentiation of the forms 

 produced by it, is not a thickening of a substantive entity, but is sim- 

 ply an increasing complication in the relations in the establishment of 

 which all realization consists. The energy which forms and maintains 

 the higher and more definite forms of material existence has to over- 

 come and to hold its own against not only the inherent energy of the 

 primary physical form, but against the specialized energy of the inter- 

 mediate forms as well. 



I ought, perhaps, to observe here that, whenever energy is seem- 

 ingly destructive, it is in reality reconstitutive of a conservative sys- 

 tem of a lower grade. 



But I must not be led into discussions which belong to special 

 science, and are in strictness foreign to my theme ; and, so far as I am 

 at liberty to enter upon these discussions, especially in the field of 

 chemical science, they must be reserved for another article. 



♦•♦ 



SKETCH OF DE. J. W. DEAPEE. 



THE period from 1830 to 1870 is very strikingly marked in the 

 history of science. It opens with great discoveries in electrici- 

 ty, and closes with very brilliant ones in light. Its middle portion 

 is illustrated by the application of chemistry to physiology, which led 

 to a revolution in the latter science, and indeed changed the face of 



