July 12, 1889.] 



SCIENCE. 



29 



by the works being closed for three days, during which time the 

 men have absolute license to get drunk if they feel so disposed, the 

 fact being that about one per cent avail themselves of this privilege. 

 Drunkenness at another time is followed by dismissal. The mar- 

 ried workmen are provided with comfortable cottages surrounded 

 by gardens, and with rents varying from six to twelve francs a 

 month, according to their size and location. A bonus is secured 

 to them on each addition to their family, in the shape of a monthly 

 reduction in their rent ; and long service also secures a further re- 

 duction. By this arrangement the cottages gradually fall into the 

 absolute ownership of the workmen, and a most powerful induce- 

 ment for steadiness and content is thus secured. The single men 

 are also allowed to have a plot of garden if they desire it, and this 

 is found to be a great attraction in taking and keeping service un- 

 der M. Decauville. The result of this wise administration is seen 

 in the fact that the Petit-Bourg colony possess savings to the ex- 

 tent of 200,000 francs, which are not invested in savings banks, but 

 in the works themselves, where it receives a guaranteed interest at 

 six per cent. Workmen are insured against all accidents by M. 

 Decauville, who encourages and assists the several benefit socie- 

 ties, which are mainly supported by the workmen themselves. But 

 the glory of Petit-Bourg is its theatre, — a substantial and really 

 elegant building, loo feet long and 39 feet wide, capable of seating 

 about 500 persons. This theatre is nicely fitted up, and has 

 a capacious stage, with appointments that would do credit to 

 many a provincial town. Here about four performances are given 

 a year, not by third-rate actors representing sensational drama, 

 but, when it is determined that a performance shall take place, 

 subscriptions are raised among the employers, the foremen, and 

 the men, a committee is formed to negotiate with some good Paris 

 company, and every thing is arranged admirably. It may be men- 

 tioned, in passing, that the " Maitre des Forges " is a never-failing 

 favorite. But, besides theatrical performances, the theatre at Petit- 

 Bourg serves other purposes : it is the gathering-place on all politi- 

 cal occasions, at which, needless to say, M. Decauville presides in 

 his capacity as Monsieur le Maire ; it is the scene of numerous 

 concerts given by the Petit-Bourg band, formed exclusively of 

 Decauville workmen ; the corps of Sapeurs- Pompiers, also from 

 the works, hold their meetings and celebrations here ; and in the 

 theatre M. le Maire distributes prizes gained in the schools which 

 he controls. 



Altogether the Petit-Bourg colony leads a happy and prosperous, 

 though a laborious life ; and if M. Decauville can succeed in the 

 future, as he has done in the past, in saving the district where he 

 and his family have ruled for so many generations from the con- 

 tagion of discontent and communism, Petit-Bourg will continue in 

 its prosperity, and its hard-working population will remain con- 

 tented. 



THE TRANSMISSION OF ENERGY BY COMPRESSED 

 AIR. 



We have not before us any data to show the actual development 

 of the Compagnie Parisienne de I'Air Comprime, but a statement 

 of the number of installations in active work towards the close of 

 last year will serve to give an idea of the number and variety of 

 industries which have availed themselves of this means of obtain- 

 ing motive power. Since then, the number of subscribers has 

 largely increased, and one section of the great public lighting 

 scheme of Paris has been carried out by the company. At that 

 date there were, says Engineering, seven central stations fed from 

 the installation at St. Fargeau for the distribution of electric light. 

 They represented a total force of 750 horse-power given off by the 

 air-motors ; and of these, six were of 100 horse-power each. Four 

 theatres, fourteen cafes and restaurants, two hotels, the same num- 

 ber of newspaper-offices and of clubs, and sixteen private houses 

 were electrically lighted by the same means. Sewing-machines 

 were driven in thirteen different establishments, ice was produced 

 in four, and the air formed the motive power for driving machine- 

 tools in thirty-four different shops. Sixteen printing-offices availed 

 themselves of the same means, and in thirty-five other establish- 

 ments it was also employed.' Among the various applications 

 there were a number of sanitary establishments that were on the 



list of subscribers ; in six instances it was employed for raising 

 wines and spirits ; it was also used for working lifts, shearing met- 

 als, and cutting stuffs, for ventilation and for driving mills, and to- 

 a large extent for wood-working machinery. At the end of last 

 year, over 1,200 horse-power was distributed daily through the 

 mains. Of this, 478 horse-power found employment among 276 

 subscribers for various industrial purposes, and 803 horse-power 

 was absorbed in supplying 6,220 incandescent lamps and 145 arc 

 lamps. Since that date, the demands of subscribers have gone on 

 increasing until the reserve of engine-power at St. Fargeau was of 

 necessity absorbed to supply the existing demands, and it became 

 necessary to extend the main station. At the end of last year the 

 situation of the company appears to have been as follows : the 

 subscribers who had made themselves liable for periods of from 

 five to ten years brought in a revenue from various industries of 

 Si2,ooo; for lighting, of $92,000; and for the pneumatic clocks, of 

 $19,400. Besides these, there were a number of subscribers who 

 paid by the records of their counters. Of these, $14,600 was paid 

 for miscellaneous industries, and $32,000 for electric hghting. At 

 that time, also, several important installations were in progress 

 which have since been finished. Among others was the Bourse de 

 Commerce, who spent $20,000 on an installation ; refrigerating 

 companies paying $20,000 a year, and the Eden Theatre $24,000 a 

 year ; there were also a number of miscellaneous applications, 

 amounting to $16,000 a year. These sums together brought the 

 total revenues of the company to about $170,000 a year, the ex- 

 penses being $152,000 for that part of the installation which was 

 in full operation. This sum included interest on loans at 6 per 

 cent, and interest on capital at 5 per cent. At the beginning of the 

 year the works were not running at any thing like their full ca- 

 pacity, so that a large amount of capital on which interest was be- 

 ing paid was earning nothing. The financial condition became 

 more favorable a short time later, when a large number of other 

 installations were completed. It is said that this year the company 

 will be in a position to pay regular dividends of 10 per cent upon 

 its share capital ; and, if all that is claimed for the system be sub- 

 stantiated, there appears to be no reason why such a rate of inter- 

 est cannot be maintained or even exceeded. 



Engineering does not hold itself in any way responsible for the 

 figures given. They were furnished by the company, whose good 

 faith is evident, because they court investigation, and are even now 

 making arrangements for a series of trials to be conducted by 

 wholly independent experts. Naturally the most interesting fea- 

 ture of the system is that by which the efficiency of the compressed 

 air is claimed to be doubled by the application of heat and of a 

 certain proportion of water. Apart from the inconvenience result- 

 ing on the extreme cold produced at the exhaust, for large motors 

 at least, the permanent success or failure of the system depends 

 upon the high degree of efficiency that can be obtained. For small 

 motors this question is comparatively of little importance, because^ 

 even with an efficiency of 30 per cent, the balance of advantages 

 would rest with the compressed air as compared with power pro- 

 duced by other mechanical means or by manual labor. The great 

 electric-lighting installation which the company has just completed 

 between the Rue Royale and the Opera will afford, after a few 

 months, absolute data as to the relative economy of the system, 

 and a means of comparison between it and the other installations 

 of the other electric companies. Under every aspect, this great in- 

 dustry for the transmission of power, of which the station at St. 

 Fargeau is the centre, is a most interesting one ; and it may be 

 predicted with certainty, that, if the reports of independent engi- 

 neers confirm the statements by the company, applications on an 

 equally large scale will soon be at work in other cities besides Paris. 

 In a great many instances the advantage of being able to promote 

 ventilation and to obtain a supply of pure air in the workshop is an 

 advantage of great importance, and is one that is shared by no 

 other medium of energy after it has done its work. Unlike the 

 waste products from the gas-engine, or exhaust steam, or the dis- 

 charged water from a hydraulic motor, the expanded air, after 

 having done its work in the cylinder, can be turned directly into 

 the apartment where the engine is at work. There are so many 

 other purposes to which the system may find an application, that 

 its field of usefulness appears to be a very wide one indeed. For 



