This figure is a perspective view of an im- roved clamp for tinsmiths, by the same in ventor. Its nature consists in securing the heet of tin, or it may be iron, between two liscs, which have a rotary motion communi-ated to them by the cutters or cutter, as they .ct upon the sheet of metal. The upper isc has springs connected to it, by which the perator, by an eccentric pin, makes it press jpon the sheet of metal, and also releases it to hold the plate to the cutter, and take out the cut and feed in a new plate. A is the top disc; the under one is just like it. They are placed on separate spindles, a a' ) ! with their interior smooth faces together. C i j is the stock of the clnmp ; the spindle, a, is retained in the bearing stock, c, and a' in that '- | of d. The central space between the two I discs is for the reception of the sheet of tin to i! be cut, into the bottom or lid, of boxes, pans, J i c. ; f, is a clasp around a groove, e, in the shoujder of spindle a' ; near the top, e, is a , strap, and there is a spring, F, inserted in the i I stirrup foot of this strap with its tension : jdownwards, which makes the strap, E, with : iits top plate, D, and cla?p, , act on the spindle i jor, to press down the top disc, A, firmly jagainst the face of the under disc, so as to [keep them close together and hold the sheet of tin firmly between them ; h is a pin which works in a space, G, under the top plate, D, of the spring strap, E. This pin has an eccen tric knob on it inside, by turning it therefore, the plate, D, is raised, and the clasp, , raises (the spindle, a', and thus raises the disc, A, in other words, opens, the mouth of the clamp to take out and put in a plate. The disc having separate spindles, they turn easily in their bearings ; the sheet of metal to be cut is pla ced on the lower disc ; the eccentric pin, , is burned, and the spring, F, acts to clamp the sheet at once between the discs; g is a slot ind screw to move the plate, D, backwards or brwards. This is certainly a very beautiful ind excellent clamp for holding plates of me al to be cut into circles, for the bottoms of ;in vessels. The clamp is so made that discs f different sizes can be placed in and taken ut to cut large and small discs. Measures have been taken to secure a pa-ent for these usefnl improvements, and more nformation respecting them can be obtained y letter addressed to Cowing Co., Seneca Tails, N. Y. .mdash;ses-.___ A casting took place March 19th at the 1 oundry at Wool wich dockyard, Eng., of a brass i crew propeller for the Agamamnon, 91, icrew steamship, at Portsmouth. The quan-1 ity of metal required for the casting was i bout 11 tons, and the time occupied in run-i ing it first, into an iron pot made tor the ] urpose', and subsequently into the screw pro peller mould, was about 20 minutes.