PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION, 641 



experiments, on which they might have been tested, accounts 

 for the cold shoulder being given to the results they disclosed ; 

 when the mode of replenishing the exhausted power was to be 

 effected with a delay and expense and under drawbacks and con- 

 ditions, which, on the face of it, would seem to counterbalance 

 whatever advantages it might otherwise be supposed to possess. 



The distance to which cars, designed to convey the same 

 number of passengers as those in common use, on our city routes, 

 may be run, by compressed air packed up before starting, in their 

 receivers, which shall be so arranged and placed as not to inter- 

 fere with the proper accommodation of that number of persons, 

 but to be out of their view, is the point to be considered, and 

 the only point to be settled in estimating the practical advantages 

 or disadvantages of the proposed system. All else, in reference 

 to it, seems to be established by the demonstrations already 

 given. 



I have, thus far, in presenting this subject, limited myself to 

 data derived from experiments and deductions of distinguished, 

 practical civil engineers in England, whose convictions and state- 

 ments are the result of close investigation and the fruit of their 

 own experience in actual practice. 



And here I might stop, but that in so doing I should do injus- 

 tice towards other parties — injustice to my own subject and 

 violence to my own feelings, were I to omit a reference to a re- 

 port drawn up, after a "careful examination" on the system we 

 are considering, by Mr. Thomas Stetson- which report was fully 

 endorsed by Mr. Henry Waterman ,* — and, especially, if I should 

 fail to advert to the remarkable agreement, and coincidence of 

 views, there is to be found in that report, in very many impor- 

 tant particulars, with the results obtained and opinions expressed 

 by those eminent English engineers ; the fruit of whose investi- 

 gations could scarcely have been known to us on this side of the 

 water, at the time that report was submitted. The length of the 

 report and great variety of its details and calculations forbid a 

 more particular reference to it, than a few extracts will afford : 



Mr. Stetson says : ** There are no mechanical impossibilities 

 involved in the system. In this respect, the question of its prac- 

 ticability may be answered without hesitation. It is practicable 

 to transport passengers and freight at speeds as high as those 

 attained by the present steam-propelled trains ; to do it by cars 

 traveling singly, so as better to accommodate the public, and to 



