552 THE POPULAR SCIENCE MONTHLY. 



paper on " Materialism/' contributed apparently as a part of a 

 series of " Philosopliical Researches " to the periodical " Atlan- 

 tis " in 1855 ; a memorial address on Alexander von Humboldt 

 (1859) ; the earlier papers of the " Concepts/' which were pub- 

 lished in " The Popular Science Monthly" in 1873 and 1874; and a 

 " Reply to some Criticisms on the ' Concepts/ " in a later number. 

 In introducing the first of the articles in the " Monthly " (October, 

 1873), which was on " The Theory of the Atomic Constitution of 

 Matter/' the editor of this journal. Prof. E. L. Youmans, said, 

 "The depth and force of the criticism are only equaled by the 

 clearness of the conceptions and the precision and felicity of the 

 statement." 



This work is a thoroughgoing criticism of the theories and 

 concepts by which modern scientific philosophy seeks to co- 

 ordinate the facts of physics, chemistry, and astronomy. In the 

 main this philosophy assumes all jjhenomena to be reducible to 

 mechanics, and holds that the ultimate elements at which physi- 

 cal analysis arrives are mass and motion ; the physical unit being 

 an atom, hard, inelastic, inert, and passive. Since the concept of 

 atoms defines them as absolutely simple, it follows that they must 

 of necessity be equal. Yet here chemistry at once speaks in con- 

 tradiction, for the atoms, or units, currently so named, differ radi- 

 cally in properties and characteristics. In a review of modern 

 theories of the phases of energy, or modes of motion, we are 

 shown the difficulties which attend the assumption of an ether as 

 the vehicle whereby radiant energy is transferred. From the in- 

 stantaneous propagation of gravitation through space, it is argued 

 that no medium whatever may be needful for its communication. 

 The kinetic theory of gases is next examined, which theory is 

 shown to involve greater difficulties than it clears up. Next in 

 order the author proceeds to define the conditions of true hypoth- 

 esis, which in his view should both accord with all known facts 

 and simplify them. He shows how modern theorists have neg- 

 lected this canon, and supposed they were explaining a fact 

 when they were only dwarfing it, or stating it in new terms. He 

 finds more difficulty in understanding an atom than the mass 

 which it goes to make up. 



No portion of the " Concepts " is more striking than its chapter 

 on the relation of thought to things. We are pointed to the fal- 

 lacy which makes mind the measure of nature, and conceivability 

 the test of truth. The author demonstrates how the historical 

 order in which human knowledge has arisen has largely molded 

 scientific conceptions — for example, in its being supposed that 

 the solid form of matter, the first known and most familiar, is 

 more simple than the gaseous. And because impact is the com- 

 mon mode of propagating motion, ideas as to the propagation of 



