MECHANICS AND USEFUL ARTS. 73 



ingenuity and skill, consists of an arrangement of cog-wheels ; and the 

 main advantage claimed over the system now in use, is the capability 

 which this new plan imparts of varying the speed of shafting, Avhilst 

 only a pair of geared wheels is used for all the different speeds 

 required. The inventors have three models, each showing a different 

 application of the principle : one is applied to a horse-power, another 

 is for increasing the speed of a prcpsller, and the third is for an appli- 

 cation to water-wheels. A few words will explain the invention as 

 adapted to the latter use ; the motion here, however, is compound ; 

 two small wheels being employed, we should presume, to reduce the 

 dimensions to a commodious size. On the main shaft is fixed a wheel, 

 which gears into another of the same size, both resembling crown 

 wheels, although the shape of the teeth is somewhat different. Around 

 the rim of the driven wheel is another larger one, of the same descrip- 

 tion, and in fact, it is all one casting ; this last named wheel gears into 

 another fixed one of the same diameter. But now follows the main 

 departure from the old routine ; the shaft which carries the driven 

 wheels, instead of being in line, and having its further extremity to 

 revolve in a fixed bearing, is thrown, at that extremity, out of line, 

 and is attached at that end to the face of a wheel at some distance 

 from the centre on which the wheel rotates in short, it is a crank 

 motion, with the shaft acting as a connecting rod. The consequence 

 is, as the shaft is forced round by the cog-wheel, a species of rocking 

 motion is oiven to the crown-wheel on the shaft, so that the teeth are 



^5 



alternately thrown in and out of gear when the teeth on one side 

 are liberated, those on the other are thrown into gear. Such is a gen- 

 eral account of the plan ; the inventors, according to circumstances, 

 using a universal joint, &c., as may be required, to allow of the pecu- 

 liar motion. They say, in their statement, that they can vary the 

 speed as many times as the Avheel has teeth, without changing the pair 

 of wheels. Another advantage is, that the axis of the driving shaft is 

 in a line with the shafting that is to be driven. 



MACHINE FOR CRIMPLIXG IROX BARS. 



MESSRS. SLOCUM and SALES, of Lansingburgh, N. Y., have 

 recently invented a machine, for bending bars of iron into a shape 

 that is often employed, particularly for ornamental fences, house work, 

 &c., the zig-zag shape. The rolling mill employed for this purpose 

 consists of two under rollers placed side by side, and of two upper 

 rollers, the latter two running in be; rings which can slide up and 

 down in the framing, so as to recede fi o:n, or advance to, the under 

 rollers. Between these two sets of rollers there slides a bed, which 

 carries the dies intended to impress the desired form on the iron. The 

 invention particularly applies to the construction of these dies. They 

 are formed in pairs, so that the projections of the upper die fit into 

 the recesses of the lower one. Their shape, in general, is angular ; 

 and the upper die is so formed with joints, that each angular piece can 

 be forced into its corresponding cavity in the lower die, without the 



