ON THE TRANSMISSION OF POWER BY COMPRESSED AIR. 449 



long as the one which I have to put before you, and is therefore, in the 

 nature of things, impossible here. On this matter I wish to say only one 

 thing, in view of a recent discussion on the Hydraulic Power Company's 

 work in London, in which some comparisons were made between power 

 transmission by air and by water. So far as I see, the two systems at 

 present practically occupy different fields, and overlap but little. The 

 work that each appears to do best is exactly that for which the other is 

 least fitted. I see as little chance for air, just now, taking the place of 

 water for lifts or cranes, as I do for water coming into common use in the 

 driving of motors. I think it would be a pity if there were to be any 

 impression that two systems were antagonistic which in point of fact 

 rather supplement each other. Having said this much, it will, I think 

 be my most useful and most interesting course to limit myself to a 

 description of the plant and methods used in Paris, and to a statement 

 of the actual results obtained there as determined by my own experi- 

 ments on the spot. The plant and methods are by no means absolutely 

 perfect ; they are not only susceptible of, but are now receiving, consider- 

 able improvements in detail in the extensions which are being carried 

 out. In what I have to say, however, I shall confine myself entirely to 

 results actually obtained with the present plant as it was working when 

 I tested it two months ago, not giving it credit for the result of any of 

 the improvements which have not yet been introduced throughout into 

 the system of working. I shall only, after having given this statement of 

 facts, state briefly my views as to the probable practical value of improve- 

 ments which may be, or are being, carried out. 



The work now carried on by the Paris Compressed Air Company has 

 developed from very small beginnings, at first slowly, lately very fast. 

 It originated in a pneumatic clock system, which was started about 1870, 

 with a small ' central station ' in the Rue St. Anne in the centre of 

 Paris. This business grew gradually, until it became far too large to be 

 carried on from such a position, and a few years since a central station, 

 with much enlarged machinery, was established in the Rue St. Pargean' 

 which is in Belleville, about 4^ miles east of the Madeleine. There are 

 now about 8,000 pneumatic clocks, public and private, in Paris, driven 

 from St. Fargeau, and regulated by a standard clock in the Rue St. 

 Anne ; but as this part of the work, although it formed the original basis 

 of the whole system, is now a comparatively very small part of it, and is 

 of an entirely special nature, I do not propose to say anything further 

 about it here. Until two years since a pair of single-cylinder horizontal 

 ngines by Farcot sufficed for the whole work ; but by that time the demand 

 tor compressed air for working motors had so increased that extension 

 had become imperative, and the present working plant of six compound 

 condensing engines, each working two air-compressors, with the necessary 

 complement of boilers, was put down. This plant, except the compressors, 

 was supplied from England by IMcssrs. Davey, Paxman & Co., of Col- 

 chester. The compressors for the English engines were made in Switzer- 

 land on the Blanched system. The demand for power is at present so 

 great that at certain hours of the day practically the whole plant, old and 

 new, indicating considerably over 2,000 horse-power, is fully at work, and 

 in consequence a dnplicate main is being laid throughout, and newenfines 

 and compressors, half of them constructed by Davey, Paxman &°Co., 

 and half by John Cockerill & Co., of Seraing, are being pushed forward 

 as rapidly as possible. 

 1889. 



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