112 ANNUAL OF SCIENTIFIC DISCOVERY. 



In another machine, emanating from the same inventor, the forcing 

 of iron into a certain class of shapes, is performed with expedition 

 and certainty. In this machine a roller is mounted upon a carnage, 

 in such a manner that a large portion of its periphery projects out- 

 wards, free from the carriage. 



Two such carriages, each with a roller, are located opposite to each 

 other, and are capable of being moved by machinery back and forth 

 through a certain distance ; each roller being opposite to the other, 

 and located between its own and the other carriage. These carriages 

 are, by means of guides, forced to move in curved lines of any given 

 shape, and these guides can, while the machine is in motion, be forced 

 to approach or recede from each other. 



An iron rod properly heated is, while the carriages are in motion,, 

 placed in a check or tongs capable of revolution on a centre in such 

 manner that the rod passes between the two carriages and their 

 rollers. The carriages are now caused to approach, and as (hey ap- 

 proach they reciprocate, and their rollers touch the rod; the latlor 

 commence to revolve and draw out the iron. The rod is also revolved 

 continuously or through a given arc, and then stopped and moved 

 again. By a continuation of these motions, figures of revolution, gen- 

 erated by various curves or figures of polygonal cross section, and 

 regularly irregular longitudinal section, are forged out with great 

 speed and precision. 



Improvement in Locks. The following interesting notice of several 

 improvements jn locks is given by Mr. Ben wick, the examiner of this 

 Department : 



The lock exhibited by Mr. Hobbs at the World's Fair, which, in 

 connexion with the lock-picking achievement of the same gentleman, 

 created so great sensation in this country and in England, was pa- 

 tented in its most approved form in 1851 ; its great feature of security 

 having, however, been invented by, and patented to, the same inventor 

 several years since. The following is a brief description of its con- 

 struction and arrangement : 



In an ordinary tumbler lock and bolt, which is a sliding piece of 

 metal which has projecting from it a pin, this pin, when the lock is 

 on the door, usually projects horizontally towards the face of the lock. 

 Between the bolt and this same face lie one or more thin metal plates 

 which slide up and down vertically, but cannot move horizontally. 

 One edge of each of these tumblers abuts directly against the pin 

 above named when the bolt is shot. Now, it is clear that, to move the 

 bolt back, one must either break the pin or move the tumblers out of 

 the way ; but these are so long that they cannot be moved up suffi- 

 ciently far to let the pin pass below them, nor down far enough to let 

 the pin pass above them ; the top or the bottom of each tumbler, in 

 the one case or the other, striking the lock-rim, or some firm stops, 

 which prevents its further motion. Each tumbler has, therefore, cut 

 in it a long, nearly horizontal, slit of the precise width of the pin, 

 and if by any means each tumbler can be moved so that its slit comes 

 opposite the pin, then will the pin enter all the slits at once, when the 



