THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[.January, 



vaporiser (A), which it thus keeps regularly supplied, and is 

 alternately vaporised and condensed. 



THE COMBINED VAPdlR KMUNK. 



References to Engraving. 



A, Vaporiser of the perchloijde, serving also as a condenser of the steam. 

 B, Condenser of the vapour of the perchloride. — C, Cylinder in which the 

 steam acts. — D, Cylinder in which the vapour of perchloride acts. — E, Air- 

 pump withdrawing the water resulting from the condensation in apparatus 

 A. — F, Air-pumps withdrawing the perchloride after condensation in appa- 

 ratus B, and conveying it hack to feed-apparatus A. — G, Pump re-conveying 

 the condensed steam to feed the steam-boiler. — H, Pump to supply water to 

 the apparatus used to prevent the escape of the perchloride ahout the piston 

 rods. — I, pump conducting cold water from the well to apparatus 15, to con- 

 dense the perchloride vapour. — J, Apparatus tn cunse the vacuum in the dif- 

 ferent parts of the engine where the perchloride at:ls. 



No. 1, Pipe thriiugli which the steam is supplied to cylinder C. — 2, Pipe 

 through which the perchloride vapour is supplied to cylinder D. — 3, Pipe 

 through which the steam esc.npes for condensation in apparatus A, after hav- 

 ing performed its work in cylinder C. — 4, Pipe through which the perchlo- 

 ride vapour escapes for condensation into apparatus li, after having per- 

 formed its duty in cylinder D. 



We take the followinir extr.ict from the Report of the French 

 (lommissioiuM's, apjiointed in 1846, to test the capahilities of the 

 (omhiiied \'a|>oiir Engine, wliich extract explains tlie principle of 

 the engine, and tlie mode and result of tlie experiments thereon : — 



"Tlie etiier-liydric apparatus was constructed in consequence of 

 the favourahle o]iinioii jjiven hy the Board of Works as to the 

 |)ossihility of makiii;,^ use of the calorie lost in the ordinary mode 

 of condensation to vapcu'ise ether. Two engines, of 10-liorse 

 power each, were coupled upon tlie s.ime heam: the one sup])lied 

 from a holler (for lO-horse power) nets in the usual manner, hy 

 the intro<l«ctioii of steam and its discharfre after exjiansion. The 

 condensation of this steam takes place in a receiver cimtaininp;' a 

 numher of small tuhcs previously filled with ether. This litpiid, 

 owinff to its avidity for caloric, rohs the discharged steam of its 

 heat, and is vaporised at a pressure de])ending upon the tempe- 



rature and volume of the discharged steam. The other engine, 

 identical with the former as to its diameter and the motion of its 

 piston, works under the influence of ether- vapour: it receives this 

 vapour during a portion of its motion, and discharges it after 

 expansion into a receiver, similar to the former, kept constantly 

 at a very low temperature hy a continual injection of cold water. 



"Taking care to adapt to each engine a proper expanding appa- 

 ratus, we are enahled to regulate, at will, the introduction and the 

 expansion of vapour in each cylinder, and thus combine these two 

 elements of power — expansion and volume of steam for the former, 

 and expansion and volume of ether-vapour for the latter; so as to 

 arrive at a total maximum force, with the smallest expenditure of 

 steam, or, which is nearly the same thing, with the smallest ex- 

 penditure of fuel. The working of the two engines was satisfac- 

 tory, and the apparatus fit to be employed without any alteration 

 whatever in its construction. 



''Having once ascertained the certainty of its ability to work in 

 perfect security, we have endeavoured to ascertain the force de- 

 veloped under the three following cases: 1st, of a steam-engine 

 working alone by waste steam; 2nd, engines coupled, the one 

 put in motion hy the expansion and condensation of steam, and the 

 other likewise by the expansion and condensation of ether; 3rd, 

 of an engine working alone by expansion and condensation of 

 ether. 



Force produced. — "The index was placed over the cylinders 

 during the various experiments ; a lever acted constantly on the 

 main axle. The general conclusions we arrived at are as follows : 

 — As regards the force measured upon the piston by means of the 

 index. The diagrams drawn hy the ether-vapour exhibit always 

 an excess of power over those drawn by the steam. The final 

 ]iressure of the ether is generally greater than that of the steam ; 

 rarely upon a level with it, hut never less. The two cylinders 

 being erpial, it follows that, when a volume of steam is discharged 

 at a given pressure into the ether-vaporiser, a volume of ether- 

 vapour is obtained — at the very least, equal, and of the same pres- 

 sui"e. Several times an excess of pressure was gained of 10, 20. 

 and 30 per cent., with an equality of volume. If then we con- 

 sider the combined effects of these engines proportionally to the 

 niean pressure given by the diagrams, we must conclude that, bj' 

 the em])loyment of ether, a force measured by 100 becomes at 

 at least 200, at times 210, 220, 230, with the same expenditure of 

 fuel. 



"Thus have we verified and evidently exceeded the inferences 

 drawn from the experiments made in 184-6 at M. I'hillippe's, and, 

 consequently, confirmed the faviuirahle conclusions in considera- 

 tion of which the Council proposed a more decisive trial, to as- 

 certain whether the use of ether doubles the power without adding 

 to the consumption of fuel. 



"Extract made from the diagrams of the index, taken from ob- 

 servation of the arm of the lever, placed so as to measure the 

 power of the two engines cinipled together, the lever gave 80, 90, 

 105, and even 120 kilogrammes, at 40 and +6 strokes, the weight 

 attached to the lever in the experiment being from 38 to 4-2 

 kilogrammes. The steam-engine, hy itself, was unable to lift 

 the "weight attached to the lever, being from 38 to 42 kilo- 

 grammes: it stopped immedi.-ttely upon tightening. The ether- 

 engine, by itself, lifted it without difficulty, with a load of ahout 

 200 kilogrammes and more; that is to say, that a direct and con- 

 tinual injection of steam into the ether-vaporiser, produced upon 

 the ether-engine alone the maximum of work given hy the lever." 



The inventor observes: "The Rejiort omits to take notice of 

 the vacuum, which in this engine gives a jxiwer of as much im- 

 jiortance as the power of both vapours combined. An examina- 

 tion of the gauges affixed to the engine at Mr. Home's, will ex- 

 plain my meaning. The pressure of steam on its entrance into 

 the steam cylinder, as given by the indicator, was only 5 lb. i)er 

 square inch (the piston making 46 strcdves per minute); whilst the 

 power of the vacuum, caused by the condensation of the steam, 

 and acting in conjunction with it, upon the piston in the steam 

 cylinder, as given by the indicator, was double, viz., 10 lb. per 

 square inch : total ])ower exerted in steam cylinder, 1 5 lb. per 

 square inch. — In the other or perchloride cyliiuler, the expansion 

 of the vapour was equal to a power of 21 lb. per square inch, and 

 the vacuum ot 8 lb. only: together, 29 lb.; or an average pressure 

 in the two cylinders combined of 22lh. jior square inch, without an 

 expenditure' of more fuel than is necessary to produce a power of 

 steam of 5 lb. per square inch." 



