A hot blast with a cool tweer fape are points so apparently irreconcilable, that at first it would seem impossible to combine them except by means of a complicated device. But it has been accomplished in the device sliown in the accompanying engraving, the simplicity of which is equaled only by its efficiency and durability, it having for two years been in successful use both in this country and England. We gave an illustrated description of a tweer on a similar plan, in Kb. 26, Vol. XV, of the SCIENTIFIC AMERICAS, but since that publication it has been greatly improved by the inventor. The advantages of a hot blast in the working of iron and steel are too well known to be questioned or described; we will therefore confine ourself to a description of the implement itself. A is a tank, either of plate iron, zinc, or of wood, of any convenient form (a barrel will do), placed back of the forge, or in any convenient situation, so the level of the water it contains is above the tweer. The length of pipes connecting with the tweer is not material. The blagt enters the drum, B, and passes through the pipe, C, impinging on the face of the tweer and reaching the fire through the pipe, D, and nozzle, E. This nozzle is a tollow casting, seen, and is filled with water from the tank by means of the pipe, F. The steam that isgenteffted in the nozzle is conveyed igk to the tank y the pipe, G, and condensed, When the forge is to be left un-lighted, as on. nights, and Sundays, or holidays, and freezing is apprehended, the water may be drawn from the nozzle by means of the cock on the pipe, F, between the tweer and tank. In this case the flexible extension of the pipe, F, seen coiled on the floor of the tank, is raised and its end allowed to hag over the edge of the tank, so that no more water can pass from tie tank ttfthe tweer. A jointed pipe of iron may be used instead of the flexible pipe, if desired. It will be seen that the water entering the tweer nozzle is kept in a constant state of circulation by means of the steam created by the heat, and the face of the tweer nozzle is kept cool while a hot blast is passing through it. The tweer box is about fourteen inches long, ten wide, and eight deep, giving an ample chamber for the heating of the air before it reaches the fire. I The London Ironmonger, of Sept.. 30, 1868, speaks in very high terms of the actual working of the device. It has also received the unsolicited commendations of a large number of practical smiths in this country and England. All concur in the statement that the iron can be heated in one third the time usually required, with a corresponding saving of fuel, and that the heat is softer and more suant, nofriburning the surface before the interior is reached. Patents for the United States were obtained through the Scientific American Patent Agency, Aug. 7, 1866, Sept. 17, and reissued Dec. 17, 1867. Letters patent for Great Britain, France, and Belgium, have also been obtained by John Baylisa, who may be addressed at the corner of Lexington avenue and Fifty-fourth street, New York city, where the tweer may be seen in constant operation. Orders may be also addressed to Hollis, Kirkup & Co., No. 2l Dey street, New York city. Adjustable Lathe Tool Post No machinist can deny the advantage of siich a tool post to his lathe or planer as will allow the cutting tool to be presented to the work at any desired angle, without the necessity of blocking up, or a resort to similar make-shifts. Such a one is certainly prr nted in the accompanying engraving. Wb have been much gratified in an examination of the model; it seems to meet every requirement, except the positions of high t and forward and back movement, and even thege it partly compensates for. The tool stock, A, is bolted to the carriage in the usual way, and is moved forward and back, and raised and lowered in the ordinary manner. The rise, B, of the stock ig bored from the under Bide, leaving a semicircular seat, as seen, for the reception of the bottom, C, of the tool post, turned to fit the seat. This arrangement constitutes a ball-and-socket joint, The Washer, or flange, I), plain on its upper surface as that on any common tool post, is hollowed on its under side to fit the semicircular apex of the rise of the tool stock, making another ball and socket joint. The set screw sejsxjs, as usual, to hold the tool in any position; and the dotted lines show various positions of the post, C, and tool, E. No machinist can fail to see the great advantage this adjustable tool post has over those ordinarily uSed, either for the lathe or the; planer. There can be no doubt about the holding of the cut- [ ter in any position, as the frictional surfaces present a very large area, and if they had a bearing only of simply a circular line, we think no resistance the tool at its point would i meet would be sufficient to overcome U. It can be applied to any lathe or planer now in upe, and we are so favorably impressed with this device-, that if we were in our old business, we should not hesitate to give it a fair trial. By a careful examination of the device every progressive machinist will see that it is one of the simplest as well as one of the most useful of contrivances yet presented to his attention. Patented May 13,1868-, by Wm. H. Leach, assignor to him-I self and Bradford Stetson. Orders should be addressed to the agents of the patentees Horace McMurtrie & Co., 80 Milk st., Boston, Mass,