On page 17, Vol. 8, of the SCIENTIFIC AMERICAN, we gave a full description and explanatory engravings of this apparatus, which was intended to be applied to sugar vacuum pans, or steam engines. SInce that time, Mr. Miller has considerably improved on his apparatus, and on the 20th of May, 1856, he obtained a patent for these improvements, which are intended for the above uses, and give a more perfect and equable action to the arrangement, save fuel, !lnd a void the sudden expansion and contraction of the metal. In our engravings, Fig. 1 represents the condenser as applied to a common engine, in which A is the boiler, sending steam through the pipe, B, into the steam chest, C, from whence it passes into the cylinder, D, and after having performed its work, the waste steam is exhausted through the exhll.ust pipe, E; into the cylindrical condenser, F. When it has arrived in F it passes down the inside of condensing tubes in its interior, (a section of which will be fonnd in the volume above referred to,) and through a plate, H, dividing the condenser into two parh, into three or more worms in G. From the condenser, steam, air and gases are drawn by the up stroke of the pump, I, through the pipe, J, and at the down stroke of the pump, ,all the above are forced through the pipe, K, into the air chamber, L, the object of which i, to afford a space in which air and other galles can accumulate, together with any oil or other impurities which are let off from time to time by the cock, l, while the pure water passes through the pipe, M, into the cyli nder, F, outside the condensing tubes, where it acts as a condensing fluid for the wasto steam that is being drawn through their interior. From F it is still forced outward through pipe N into the boiler, at only 700 Fah. less than tho original heat of the steam in the boiler Fig. 2 ill a plan of the worm in its case, G, abo showing the plan of the condensing tubes in F, above the plate, H, half of which is taken away, to show the worm. The condensing tubes are arranged as shown at a, the exhanst pipe, E, being turned round, to show the construction of the worm, around which, in G, a stream of any kind of cold water is at g. The steam entering at E, passes down the central main, D, and into the condensing tubes, a; from them the water flows into the. central tube, c, which 1I ... 88S t1aougb. plate, H, and leads to the four rows of worms, d, being now in the fluid atate, and to the ehamber, e, which is connected to J, leading to the pump. The arrangement of the four rows of worms will be understood by the section As the condenslllg tune. or cnamOllrs 01 tl118 condenser aro not like a continuous pipe in other condensers, through which the steam rushes in a continuous torrent, the steam is suspended for an instant in the chambers, in its motion; and it is claimed that this method of action allows of its more rapid condensation by being presscd ngainst the colder surf ace of the pipe, where the heat is c:uried off. While It vacuum is maintained in any part of the condenser in connection with the cylinder, as in the worm part under the tubular chamber, the condensing action may be as rapid as If the perfect vacuum chamber were nearer the cylinder, just in the lama manner that a. VIlCU1Ull is ma.intained in the hot cyUndar itself, while the condeuser mlly be removed. from it. In an inside oondenser the temperature is maintained about 100" Fah.; and the feed water taken f rom it to supply tho boiler c(lnnot be above the same heat, bocause it would boil in the vacuum, and tlie pumps conld not operate; but as thli vacuum is maintained behind the pump in this condenser, the feed water from the worm passing through the upper part of the condensing chamber to the boiler, takes up some of the heat fl'om the e'5:haust steam, all of which is saved and returned to the boiler. The last patent of Ur. Miller does not claim any mechanical arrangement except the separation of the condensor into two parts, to act as a condenser for the steam, nnd for heating the pure water of coudensation before entering the boiler. The lower part aets as a cooler to the water of condensation beforo entering the air pump, in order to prodnce a good vacuum. Further information can be obtained by addressing James M. Miller, !l2 Mniden Lane, New York, who has in his possession tho highest testimonials from many eminent practical.