August 18, 1905.] 



SCIENCE. 



207 



belief, and to show that the laws of increasing 

 and diminishing return are universal laws; 

 in other words, that they are laws of universal 

 evolution. In the present article I attempt 

 only to offer a tentative formulation of these 

 laws, and to present a few of the more obvious 

 and important explanations that they suggest 

 of certain specific phases of evolution, such as 

 natural selection and survival. 



In the evolutionary process ^outlay,' instead 

 of being made in terms of labor and capital, 

 as in industry, is made in expenditures of 

 energy, that is to say, in dissipations of mo- 

 tion. The ' return ' for this outlay is the 

 - total amount of compound evolution. Under 

 certain conditions an increasing expenditure 

 of the energies — original and subsequently 

 acquired — of an aggregate, results in evolu- 

 tionary changes that extend or multiply more 

 rapidly than the expenditure of energy in- 

 creases. Under other conditions, evolutionary 

 changes extend or multiply less rapidly than 

 the expenditure of energy increases. 



Chief among the conditions here referred 

 to as determining the rate of evolutionary 

 change, the important ones are, first, the 

 heterogeneity of the elements or materials 

 entering into the aggregate, and, secondly, 

 the kind or quality of the materials. 



In homogeneous bodies or aggregates con- 

 centration bears a constant ratio to the loss of 

 internal motion, but in heterogeneous bodies 

 there is no such constant ratio. Concentra- 

 tion may proceed more or less rapidly than 

 the loss of energy, according to the composi- 

 tion of the mass. 



Different forms of matter differ one from 

 another in their capacity to contain motion 

 with a given concentration of their particles. 

 That is to say, they differ one from another 

 in energy-storing, energy-conveying and en- 

 ergy-transforming capacity per unit of volume 

 and weight, as is seen, for example, in the 

 unequal capacity of woods and metals to con- 

 vey heat or to transmit electricity. 



The general laws which formulate the rela- 

 tion of these facts to the rate of evolution are 

 these : 



1. In a heterogeneous aggregate the amount 



of transformation, i. e., of compound evolu- 

 tion, increases more rapidly than the dissipa- 

 tion of motion if, in the composition of the 

 aggregate, materials of a higher are being 

 substituted for materials of a lower capacity 

 — per unit of weight and of volume — to store, 

 convey and transform energy, and are being 

 maintained in a perfect working correlation. 



2. Conversely, the amount of compound 

 evolution increases less rapidly than the dis- 

 sipation of motion if, in the composition of 

 the aggregate, materials of a lower are being 

 substituted for materials of a higher capacity 

 ■ — per unit of weight and of volume — to store, 

 convey and transform energy, or if they are 

 not maintained in perfect working correlation. 



Two or three simple illustrations derived 

 from economics must here suffice as examples 

 of innumerable facts upon which the demon- 

 stration of these laws rests. 



Increasing the returns of a factory of given 

 floor space by increasing the speed of ma- 

 chinery is possible only if for mechanisms of 

 poorer quality there are substituted boilers, 

 shafting, gearing, etc., of great cohesive 

 strength, and great tensile streng-th in pro- 

 portion to weight and volume. 



The increasing returns of a department 

 store, in proportion to capital invested, have 

 been made possible by the substitution of such 

 devices as the light and diminutive cash car- 

 rier apparatus for the relatively clumsy mech- 

 anism of a sufficiently large staff of men and 

 women, or boys and girls, to perform a like 

 function. 



The mechanically and commercially possible 

 ' skyscraper ' has been made possible by revolu- 

 tionary changes in building materials and 

 construction, including a substitution of light, 

 but immensely strong, steel frames supporting 

 the outer walls as well as the flooring, for 

 massive outer walls supporting an internal 

 structure. 



These laws of evolution are, I think, the 

 basis and exi^lanation of the phenomena of 

 natural selection and survival. 



In any finite aggregate of competing things 

 or organisms, those survive in which the total 

 amount of evolutionary transformation in- 



