178 



SCIENCE. 



[N. S. Vol. XXIII. No. 579. 



this element can affect water powerfully is 

 shown from the circumstance that its sul- 

 phate crystallizes with seven molecules of 

 water of crystallization. 



The values of A are not, except in the 

 cases of hydrochloric acid, magnesium sul- 

 phate, and of sulphuric acid, already cited, • 

 the same as the heat capacities of the mole- 

 cules of the solute, but are larger than they 

 are. It is hard to account for this as we 

 did in the corresponding case of the in- 

 creased heat capacity of the non-electrolytes 

 when they were in solution, by supposing 

 an increase in their own degrees of free- 

 dom. We are led rather to suppose that 

 the molecule of solute affects the surround- 

 ing water so as to increase its heat capacity. 

 On the assumption that the number of 

 water molecules affected is 8, except in the 

 case of the two compounds containing 

 potassium, and that for them the number 

 is 14, we get in general the value 3 for the 

 change in the heat capacity of each water 

 molecule affected, or an increase of one 

 sixth its heat capacity. 



Of course such statements as these are 

 merely suggestions. I hope that in time the 

 specific heats of electrolytic solutions will 

 be so accurately knowm as to make it pos- 

 sible to feel certain whether or not a law 

 really obtains in the values of the constants 

 of the formula. 



Considering the bearing of the relations 

 that have been adduced upon the general 

 question of the equipartition of energy, it 

 seems to me that their general consistency 

 with that principle, especially the way in 

 which the heat capacities of the organic 

 compounds can be portioned out among the 

 atoms by means of simple assumptions 

 about their degrees of freedom, does afford 

 some confirmation of the principle. Mere 

 chance can hardly account for so large a 

 number of successful coincidences. 



W. P. Magie. 

 Princeton University. 



TJf AN SPORT ATION AND COMBINATION} 



We are so constituted that each of us 

 looks at the problems of life from a some- 

 what different standpoint. The opinions 

 we form, the principles we uphold, the 

 policies we advocate, are all influenced 

 more or less by the work in which we en- 

 gage and the kindred range of our reflec- 

 tions. It is natural, therefore, that I 

 should find the origin of many present-day 

 questions in the facts of modern trans- 

 portation and communication, and that I 

 should entertain views, perhaps indulge in 

 fancies, which those facts suggest. 



The primitive man traveled on foot and 

 moved his scanty belongings by carrying 

 them in his arms or on his back. Even the 

 rude vehicles and water-craft which he 

 eventually learned to construct were pro- 

 pelled by his own muscle, and we can only 

 guess how long it was before he obtained 

 any other motive power for the transfer of 

 his person or his property. In every way 

 his life was meager and isolated, for he had 

 not acquired the art of writing, and inter- 

 course with his fellows was confined to 

 ordinary speech. Outside the family to 

 which he belonged, or the tribe with which 

 he gathered, he had no community of in- 

 terest, felt no friendship and desired no 

 alliance. Sis associations were as limited 

 as his means of conveyance. 



In a later but still very remote period 

 there came a great increase of motive power 

 by the subjugation of animals, and their 

 employment for transportation on land, 

 and by the use of sails and ruddei-s which 

 multiplied many times the efficiency of 

 water carriage. When these two results 

 were secured, man had added to his own 

 bodily powers the superior strength of 

 beasts of burden and the enormous energy 



' Address of the vice-president and chairman 

 of Section I — Social, and Economic Science, 

 American Association for the Advancement of 

 Science, New Orleans, 1005. 



