700 



THE POPULAR SCIENCE MONTHLY. 



Professor Jevons has been at some pains to 

 investigate the bibliography of the subject, 

 and finds it surprisingly full and of consid- 

 erable value. 



It appears from his researches that the 

 theory, as stated by him, and in a form 

 closely resembling his, by M. Leon Walras, 

 of Lausanne, has been anticipated in its 

 chief features by Gossen, of Germany, and 

 Cournot, of France. This is somewhat re- 

 markable, as these writers worked not only 

 independently of each other, but with little 

 or no knowledge of what had been done by 

 any others. They had, in fact, to begin at 

 the beginning and work out the entire sub- 

 ject for themselves. Professor Jevons re- 

 gards this independent arrival at substan- 

 tially the same views of the " fundamental 

 ideas of economics," by four different in- 

 quirers, as strong evidence of their probable 

 truth. He appends to the present edition 

 of his work a fuller list than was possible 

 in the first of all the writers whose names 

 he has been able to discover, who treat the 

 science on this side, that future students 

 may not remain in ignorance of what has 

 been accomplished. 



The present unsatisfactory state of 

 economics is regarded by him as due to the 

 failure, on the part of economists, to dis- 

 tinguish between several branches of knowl- 

 edge which, though closely allied, are yet 

 separate. There should be a distinction 

 drawn between the abstract science which 

 has to do with the fundamental relations of 

 economic quantities and those special con- 

 crete scieAces which depend upon it. The 

 relation of this abstract science to the con- 

 crete ones he holds to be somewhat analo- 

 gous to that between the science of me- 

 chanics and the physical sciences, all of 

 which have their basis more or less in it. 

 Pleasure and pain are, according to him, the 

 ultimate factors with which economics has 

 to deal, and how to increase the one and de- 

 crease the other to the greatest extent pos- 

 sible is the problem to be solved, or, stated 

 more specifically, the problem is : " Given a 

 certain population, with various needs and 

 powers of production, in possession of cer- 

 tain lands and other sources of material; 

 required the mode of employing their labor 

 which will maximize the utility of the prod- 

 uce." In order to subject the science to his 



analysis, Professor Jevons introduces into 

 economic quantities the physical conception 

 of dimension. These quantities can then 

 be treated geometrically, and their various 

 relations expressed by formulas. A feeling, 

 such as a pleasure or a pain, he considers 

 possessed of two dimensions, intensity and 

 duration, the amount of which can be varied . 

 by varying either or both of the factors. A 

 curve whose ordinates correspond with the 

 intensity of the feeling and the abcissas 

 with its duration will express the law of 

 the variation of the intensity, when this 

 variation is continuous. 



The relations of the various economic 

 quantities involved would, in any case, be 

 known when the elements of such a curve 

 were determined, or, as the mathematicians 

 say, when the form of the function is known. 

 The agreement of the calculated result, when 

 numerical data are introduced into the for- 

 mulas, with the actual result, would be the 

 verification of the formulas. Such numeri- 

 cal data, consisting mainly in " accurate ac- 

 counts of the quantities of goods possessed 

 and consumed by the community, and the 

 prices at which they are exchanged," are 

 not now easily attainable, and formulas can 

 not, therefore, be at present verified. As 

 these data become available, however. Pro- 

 fessor Jevons thinks that the science can 

 gradually be raised to the position of an 

 exact one. 



A large portion of the present work is 

 devoted to the elucidation of the problem 

 of exchange value, which is necessarily fun- 

 damental in any economic exposition. Ex- 

 change value, or, as he terms it, " the ratio 

 of exchange," is held by him to be directly 

 dependent upon utility and only ultimately 

 upon cost of production. In his theory of 

 utility he draws a distinction between the 

 total utility of any commodity and its de- 

 gree of utility at any point of supply, the 

 person concerned being the sole judge in 

 any case considered of what is or is not 

 useful. In illustration, the total utility of 

 such a thing as food is infinitely great, as it 

 is necessary to life ; but, when we have abun- 

 dance, the utility of an addition is very small 

 and may be zero. Considering the increase 

 of supply to be made by adding increments 

 of commodity, the degree of utility of the 

 last increment added, or of that to be add-' 



