This instrument is the invention of Mr. Alexander Morton, of Glasgow, Scotland. It has been before the public scarctly a twelvemonth. yet in that brief time it has taken rank among the mOft remarkable improvement s in steam engineering of modern times. It is seemingly p aradoxical in its op eration, and therefore its action is somewhat difficult of comprehension. The principle of its operation is, however, very plainly stated in tha following extract fi'om r, paper, by James K. Napier, F. R. S., read before the Franklin Institute, O ct. 30th: "It is well kno wn that the ordinary jet condenser requires a pump to remove the air and the water used in condensation. Mr. Morton, while experimenting on a Giffard's injector, discovered that the pump could be dispensed with ; that the ex haust steam itself could do that work, that the steam after forcing its piston to the end of the cylinder had sufficient energy left to take itself, and any air with which it might be combined, out of the cylinder and produce a vacuum equal to that produced by the best OOndens'ar and air-pump of the ordinary construction. " The apparatus which he invented to enable the steam to do this work, he calls an Ejector Condenser. It is very similar in arrangement and mode of action to a Giffard's Injector. The cold water wanted for condensing the steam, if below the apparatus, is raised by a jet of steam in the same ma.nner as in iffard's or Sellers' Inj ectors." As soon as a vacuum is formed in the cylinders of the engine the steam j et is stopped by means of a double piston valve arrangement, which is adjustable as will be shown below. The condensed steam, condensing water, and air are received into a chamber or "hot well," from which the water may be drawn to supply tlie boiler ; the surplus contents of the well being discharged as is shown in the following from the London Artisan : "'rhe large engraving, Fig. 1, is a complete longitudinal section of the conden ser, in the act of being started by a small starting and regulating steam jet shown open, but which is closed automatically by the vacuum as soon as that Is formed and enabled to draw and discharge its own injection water, the valve being used to restore the vacuum when required. This regulator is considered an important part of the practical application of the apparatus, and has been remarked. as such by most engineers who have seen it, although other arrarigements) for a regulating valve might be made, and equally well worked by the action of the vacuum, for the a.m.e purpose. "'fhe exhaust steam, entering from the exhaust steam branches, after surrounding the injection branch passes on to the parts A and B respectively, where it meets the condensing stream of water, and is condensed and carried away through the pipe C. The starting and. regulating valve is remarkably ingenious. It consists of a piston valve for regulating the admission of steam from the boiler or main steam pipe into the steam jet, for the purpose of assisting the current of injection water whon the vacuum is not so perfect as to effect this in sufficient quantity, unaided. The chamber behind the piston of tho regulating valve is connected by a small I'ipe "with one of the exhauist pipes, as shown ; so that the vacuum wli.cii ,:t]'ong enough shuts the valve a,gainst the power of a small helkal spring, which is so adjusted as to adn:,it the inithl tcam tho moment the vacuum falls below what is necessary to keep up a sufficient stream of condensing water through the condenser. Thus a jet of fresh steam is in-stan tly supplied when necessary. A small spindle on the piston passes out through the end of the chamber, with a thumbscrew on it, by which the valve may be held open to enable the engines, aft er standing still, to work with full power and vacuum at any moment, being made eelf-acting again after the engines are fairly at work. The starting steam jet, conducting the steam to the point of the water nozzle, is formed conoidltl at the point, and actuated by a handle to regulate the quantity of injection water allowed to pass through this nozzle. To prevent the injection water condensing the steam in the steam jet, it is surrounded by a hollow casing to prevent the direct metallic contact of the hot and cold surfaces. " Fig. 2 is a vertical section of a somewhat similar apparatus, constructed fur the lifting and forcing of water. This aijparatus is placed in the main range or length of pipes through which the water is to be raised, at any distance above the surface of the water within the limits of the atmospheric pressure. The hight to which the water can be raised in the pipes above it, depends wholly on the velocity of the actuating steam passing through the branch pipe, as shown, and regulated by a valve or cock attached to that branch, so as to act with any .desired lateral force through the annular narrow jet around the end of. the central nozzle. The water passes up by the inlet water pipe, and is forced or drawn in through the short induction central tube or nozzle by the annular jet of steam, and thence up through the main long curvilineal induction tube, or pipe C; the small induction tube a, by preference being cased as shown. The small portion of condensed steam on the outer surface of the tube is forced through the annular slit or jet at its end, into the neck of the induction tube, C, which expands in area in an increasing curve. The lateral branch pipe, made to lead into the main water pipe, close below the nozzle, is only for experimental purposes. " The action of this new condenser, although very different from that of the ordinary condenser and air pump is even more simple. The injection water in rushing into the condenser through the conoidal nozzle, attains a velocity proportional to the vacuum, and this velocity, which the jet of water retains, is found sufficient to enable it to discharge itself through the induction tube C, which is so formed, that its area increases inversely with the velocity of the issuing j et. As th e result of many experhuents, the inventor has adopted the parabolic curve shown in the engraving. The jet of water in passing through the" 'ejector condenser' no doubt Joses ome of its ener.g'y by friction in the nozzles, Dut thi s loss is m ade up by the alternate discha rges of exhaust insteam, from the cylinders in the same direction with, a nd sur- rounding the water jet. In maneuverin g the e ngi nes ah ead thumbor astern, the piston starting valve is set open, so that the central steam jet maintains a c o nst ant vacuum w hether th e engines be at work or not ; consequently they may be stopped for any period of time, and instantly started at full power when required. As soon as the engines arc fairly at work, the starting valve is disengaged, and the vacuum, as before described, shuts off the starting steam j et. The vacuum in the eondenser then becomes the regulator of that valve ; and should any person open a grea se cock, or oth erwise admit air into either cylinder, or into the condenser, to impair the vacuum, that instant the starting valve opens and admits a jet of steam to d ispel such air, and keep up the stream of in. j ection water until the vacuum is restored. 'l?he point of tll@ central spindle through which the startin,g steam jet passes, serves the purpose also of an inj ection valve, whereby more or less water is admitted by its insertion into, or withdrawal from the water nozzle by the hand I ever." The accompanying indicator diagrams were taken from the lower end of each of the two cylinders of a steam engine, having their exhaust pipes connected with the ejchaust steam branches of one of their instruments. It will be observed the vacuum is maintained remarkably steadily. The original form of the nozzles was somewhat derent from those shown in the engraving. With the present form no difficulty is experienced in maintaining an ave. rage vacuum of 36t inches of mercury. Professor Eankine has shown that by the use of this instrument all the power required to work an air-pump is saved. He estimates this saving at four per cent of the indicated power of the engine upon which he experimented. Reserve Power. It is not wise to work constantly up to the highest rate of which we are capable. If the engineer on the railroad were to keep the speed of his train up to the highest rate he could attain with his engine it would soon be used up. If a horse is driven at the top of his speed tor any length of time he is ruined. It is well enough to try the power occasionally of a horse or an engine, by putting on all the motion they will bear, but not continuously. All machinists construct their machines so that there shall be a reserve force. If the power required is four-horse, then they make a six-horse power. In this cast! it works easily and lasts long. A man who has strength to do twelve honest h ours of labor in t wenty-four and no mori" should do but nine or ten hours' work. The reserve power keeps the body in good repair. It rounds out the frame to full proportions. It keeps the mind cheerful, hopeful, hajpy. The person with no reserve force is always incapable of taking on any more responsibility than he already has. A little extra exertion puts him out of breath. He cannot increase his work for an hour without danger of an explosion. Such are generally pale, dyspeptic, bloodless, nervous, irritable, despondent, gloomy—we all pity them. The great source of power in the individual is the blood. It runs the machinery of life, and upon it depend s our health and strength. A mill on a stream where water is scanty can be worked but a portion of the time. So a man with little good blood can do but little work. Tho reserve power must be stored up in this fluid. It is an old saying among stock raisers, that" blood tells." It is equally true that blood tells in the sense in which we use the word. If it is only good blood, then the more of it the better. Whn the reserve power of an individual becomes low it is an indication that a change is necessary, and that it is best to stop expending and go to accumulating, just as the miller does when the water gets low in the pond. Such a C01183 would save many a person from physical bankruptcy.—l&raZfd o/ Health. DOUB,T, discontent, deceit, and dobt, are deadly fotjs to peace of mind.