160 MORRIS LOEB 



the other hand, must recognize the difficulty of the task of 

 tracing the influence of these causes in encouraging the con- 

 centration into large centers, in depleting the older rural com- 

 munities of their more energetic elements, and in eliminating, 

 more or less completely, that element of the village com- 

 munity which formed the connecting link between city and 

 country life of the past; while he hails the gradual extension 

 of the benefits of civilization over the entire earth. Popular 

 opinion, pointing to the reduced price of food-stuffs, clothing 

 and other comforts, to the freedom of migration for the in- 

 dividual, the wage-earning opportunities for the myriads 

 employed in the carrying trades, will unhesitatingly answer 

 in the affirmative any question as to the value of these 

 modes of communication. Public opinion on this topic will 

 doubtless be justified at that time, when the increased popu- 

 lation of the earth will demand the exploitation of all its 

 resources, the tilling of every arable field, the harnessing of 

 every horse-power. 



At the present juncture, however, the physicist cannot 

 join the chorus of praise, until he has satisfied himself on cer- 

 tain points that come more closely within his ken. For him, 

 money as a standard of comparison must 'ever be secondary 

 to the amount of energy, in the dynamic sense, requi- 

 site for the attainment of a desired object. So far as this en- 

 ergy has a market value, as in the wages for day-labor or in 

 the price of fuel, coin may form a temporary expedient for 

 casting a balance, less reliable, I fear, than most schools of 

 political economy will admit. 



I have been struck, comparing the prices of certain staple 

 commodities, as a bushel of wheat, a cow, a work-horse, with 

 a laborer's wage in ancient Jerusalem, imperial Rome and 

 modern New York, by the apparent constancy of the ratios, 

 which might well lead us to look to departures from such a 



