448 KEPORT— 1889. 



reforms would be decided, as removing one of the principal hindrances 

 to international exchange — hindrances which, moreover, affect in some 

 degree the intei'ests of every class, and are never so dangerous as when 

 they are applied with the mistaken idea of advancing national welfare. 



Experiments upon the Transmission of Pozver by Coinpressed Air 

 in Paris {Popp's Systevi).^ By Professor Alexander B. W. 

 Kennedy, F.M.S., MJnst.G.E. 



[A communication ordered by the General Committee to be printed in extenso 



among the Reports.] 



The subject of transmission of power to a distance is one of such 

 immense importance in an industrial country like our own that I am 

 sure I need offer no apology for bringing this paper before Section G 

 of the British Association. In a case such as that which I have to 

 describe to you, where the distance to which the power is to be trans- 

 mitted is great enough to be measured in miles, the possible methods of 

 transmission are not very numerous. Steam, watei', air, and electricity 

 seem to be the only four agents practically available. All four have been 

 used to a greater or less extent, and with more or less complete success. 

 In our own country the distribution and use of high-pressure water has 

 been carried out with the greatest engineering skill, and with correspond- 

 ingly great success, by the Hydraulic Power Company in London, and 

 also in Hull. Electric transmission (for traction at least) has been at 

 work on a small scale for some time in various places, and is about to be 

 tried on a much larger scale under Mr. Greathead on the Southwark 

 Subway. In America it has been very widely used for traction on 

 tramways, and on the Continent it has also been used to a certain extent 

 for power transmission for general purposes. Steam has been used on a 

 large scale in New York, but as yet its success does not seem to be un- 

 questionable. Compi-essed air has of course been used over and over again 

 in rough and uneconomical fashion in connection with tunnelling, mining, 

 and boring work, but I think only two practical attempts have been made 

 to utilise it economically and on a large scale for industrial purposes. 

 Of these two, one has been made in Birmingham and the other in Paris. 

 The Birmingham Compressed Air Power Company has established works 

 on a very large scale, but various causes have unfortunately combined to 

 cause delay in the commencement of its operations, which indeed are 

 hardly yet fairly started. In Paris, however, the transmission of power by 

 compressed air has been in operation on a somewhat large scale and with 

 very great mechanical success for a few years past. I have recently had 

 occasion to spend some weeks in making experiments in connection with 

 the Paris compressed air plant, and having been given the fullest permis- 

 sion to publish the results of my experiments, I have pleasure in taking 

 this opportunity of bringing tliem before the members of the British 

 Association. To avoid any misunderstanding I must premise that it is 

 not my intention to institute any comparison between the different 

 methods of power transmission which I have mentioned. Such a 

 comparison, to be of any value, would require for itself a paper at least as 



• Tliis paper was published in. extenso by Kngvieering ou September 10, and by 

 The Engineer on September 20, 1889. 



