ON THE TRANSMISSION OF POWER BY COMPRESSED AIR. 459 



point out various weak points in the arrangements adopted ; and yet, iu 

 spite of all such somewhat cheap criticism, the fact remains that no 

 one has yet carried out a compressed air transmission with anything 

 approaching to the same success on anything like the same scale. 

 The fact is that the success of the system has been essentially due 

 i-ather to the practical good sense with which the work has been carried 

 through than to any special novelty in the methods employed. The 

 air-compressing arrangements at St. Fargeau are in no respect novel 

 or specially perfect, they had been used over and over again before ; there 

 is no special advantage in M. Pojip's rotary motor that may not probably 

 be possessed by many other rotary motors ; the larger motors are simply 

 good ordinary steam engines such as can be bought any day in open 

 market, used without the slightest alteration. Of the fan meter it can 

 only be said that it works well enough to allow progress to be made 

 while it is being improved, and even of the coke stove one would not like 

 to say very much more. The plan of heating compressed air before using 

 it in a motor was first proposed many years ago. The great success which 

 has attended the work in Paris has loeen attained because its directors 

 have wisely chosen rather to set to work with imperfect apparatus, if only it 

 were simple, fairly effective, and ready to hand, than to wait for the 

 possible invention of novelties and improvements, or to risk the success of 

 their start by the use of any unknown or untried apparatus, however 

 promising its nature. They have had, moreover, the great advantage 

 hitherto of being always asked for more air than they could supply, so 

 that their works have grown and increased simply to meet a growing and 

 increasing demand, and (fortunately perhaps) the urgency of the demand 

 has left them no alternative but to meet it by the very simplest possible 

 means. 



I have already mentioned the great convenience and handiness which 

 a compressed air motor possesses. From the engineer's point of view 

 these qualities are most striking. The engine starts, for instance, without 

 the least hesitation, even with full brake load on, directly the valve is 

 opened, if the crank is just past the centre. This, of course, is impossible 

 ■with a gas engine, and hardly less impossible with any ordinary (single- 

 cylinder) steam engine. The absence of the heat and leakage, and of the 

 noise and smell which so often in greater or less degree accompany the 

 smaller steam or gas motors constitute a very much larger difference 

 than could at first be thought possible. But from the consumer's point 

 of view the advantages are even greater than from the engineer's. There 

 is, first of all, the complete absence of danger and of nuisance of eveiy kind. 

 There is then the great saving of space, even as compared with a gas 

 engine, and much more as compared with a steam engine and boiler. 

 There is reduction of insurance on account of the entire absence of fire 

 risk. Not only this, but the air motor seems to me completely to supply 

 that most important industrial want, a motor suitable for "small 

 industries," that is, for work carried on in woi-kmen's own houses, or in 

 very small workshops. For here it is not only mechanically most suitable, 

 but in the nature of things it can bo made to cool or ventilate, by its 

 exhaust, to any desired extent. The sanitary advantage of this in cases 

 where work is carried on in confined spaces can hardly bo exaggerated. 

 Even in a very large printing office in Paris I found an almost unbearable 

 atmosphere made quite pleasant as long as the motor was working, by 

 allowing a portion of the exhaust to come into the room. 



