3 H POPULAR SCIENCE MONTHLY. 



ances would have to be provided to transport them from the place 

 where the ship might land to the station entrance. 



It must not be assumed from what has been said in the fore- 

 going that the writer regards the solution of the problems here 

 considered as of no special value, for his views are just the oppo- 

 site of this. The object aimed at has been to show that the won- 

 derful things that it is expected will be accomplished by the solu- 

 tion of these problems will never be realized with regard to some 

 because they are not possible, and are not likely to be realized 

 by the others on account of inherent defects that the solutions 

 may bring to light. The coal-battery problem will, no doubt, be 

 worked out, in some form or other, but who can tell whether the 

 objectionable features of it will or will not offset all its advan- 

 tages ? The hot-air engine is a far more perfect converter of 

 energy, in theory, than the steam engine, but its defects when re- 

 duced to a practical form are such that it is of no value except 

 for small power, and this may also turn out to be the case with 

 the coal battery. The utilization of the energy of tides, solar 

 heat, etc., is as possible to-day as at any future time; the fact 

 that they are not utilized is proof that they are not considered as 

 desirable as other forms of energy. In the future the cost of the 

 apparatus for harnessing them may be so reduced as to render 

 them available to a much greater extent than at the present time, 

 but that they will ever revolutionize the industrial affairs of the 

 world and drive the steam engine out of use is hardly a remote 

 possibility. Aerial navigation will, no doubt, be accomplished, 

 but in the opinion of the writer it will never be used for com- 

 mercial purposes, simply because it can not, even if developed to 

 the highest state of perfection, compete with transit on the surface 

 of the earth, either in speed or cost of transportation. It may be 

 used in warfare, but more than likely it will be confined to pleasure 

 purposes. 



THE highest value can obviously be given to present research by direct- 

 ing it chiefly to those departments which are undergoing most rapid changes 

 and therefore most urgently demand immediate study. The subject is thus 

 regarded by Prof. A. C. Haddon, who, trying to put himself at the point of 

 view of our successors a hundred or a thousand years hence, asks, in Nature, 

 what they would wish we had done. Studies in the structure, development, 

 and physiology of animals, polar research and deep-sea research, will not 

 suffer materially if the pursuit of them is delayed ; but u our first and im- 

 mediate duty is to earn for science vanishing knowledge ; this should be 

 the watchword of the present day." In this category are the study of 

 native fauna and flora before they are exterminated or crowded out or 

 mixed with introduced species, and the study of native man before he 

 is contaminated by contact with civilization. The opportunity for these 

 studies is diminishing, and once lost can never be recovered. 



