MECHANICS AND USEFUL ARTS. 109 



introduced through the door, which is then closed ; motion is now 

 communicated to the horizontal cylinder, and each portion of its pe- 

 riphery in turn becomes the bottom, while the contents are rolled, or 

 turned over and over, and continually exposed to the flame which 

 passes through the cylinder on its way from the grate to the chimney. 



It is obvious that every portion of the surface of each fragment will 

 be exposed to the action of the flame, and that the mass, when melted, 

 will be continually stirred or agitated as if acted upon by the ordinary 

 rabble. I am not informed as to the fact of this furnace having been 

 practically tested, but see few difficulties in the way of its successful 

 operation, and these of such a character as may be easily remedied. 

 Another furnace of the same class, and having in view the saving of 

 the same kind of labor, has been patented by another inventor, favor- 

 ably known as a practical metallurgist. The bottom of his furnace is 

 a cast-iron table, circular in its contour, covered with brick, and re- 

 volving on a vertical axis under the ordinary fire brick roof of the re- 

 verberating furnace. Through the ordinary working door projects into 

 the furnace and over the revolving bottom a rabble connected at its 

 outer end to a slide, actuated by machinery which gives to the rabble 

 a reciprocating motion. This slide runs upon a guide whose angle 

 to the side of the furnace may be changed by the operator, and the 

 rabble is thus forced to stir over every portion of the working bottom. 



Improved Trip Hammer. An improved method of lifting the ordi- 

 nary trip hammer deserves notice, as by means of it any different 

 degree of blow within the range of the lifting cams can be attained 

 with a facility almost equal to that afforded by the steam hammer. In 

 this contrivance the cam, instead of acting directly upon a lifting leg, 

 acts upon the end of a lever, vibrating in a vertical plane, which em- 

 braces that leg. This lever is provided with a sort of toggle catch, 

 which grasps the leg firmly whenever the lever is raised, but has no 

 hold thereon when the lever is falling. A wedge enables the attendant 

 to regulate the point to which this lever shall fall. The cams in their 

 revolution strike it sooner or later, According to the distance it has 

 been permitted to drop ; and the instant that the lever commences to 

 rise, it clasps and holds the leg, forcing the hammer up a distance pro- 

 portioned to its own ascent only. 



Improvement in Anvils. A simple improvement in anvils bids fair 

 to obviate an important practical difficulty in their construction. This 

 difficulty has its origin in the heat retained for a long time in the im- 

 mense mass of metal behind, or rather below, the centre of the steel 

 face in the process of hardening, which heat prevents the rapid cool- 

 ing of the steel face, and generally leaves a soft spot near its center. 

 By forming the body of the anvil with a cavity of some size extending 

 from its bottom nearly to its face, a portion of the metal at the centre 

 is dispensed with, and facility for the introduction of a stream of cold 

 water into the centre of the mass, and almost upon the bottom of the 

 face, is afforded during the process of hardening. The center of the 

 mass is therefore cooled almost as rapidly as its exterior, and a sound 

 and equally hard face is, in consequence, a matter of easy attainment. 



