54 ANNUAL OF SCIENTIFIC DISCOVERY. 



beams, as to move a ratchet lever the exact distance required in gath- 

 ering round the teeth of the beams to graduate the let-off and take-up 

 in unison. The stop-motion is a double-finger one, which, when the 

 thread breaks, at once detaches a crank-lever, which throws the driving- 

 belt on to the loose pulley and effectually prevents all breakage. Scien- 

 tific American. 



NEW LOOM PICKER. 



MR. GEO. W. PERRY, of Fall River, Mass., has invented a new 

 mode of combining and operating a picker for power-looms, which 

 has been in operation for some time, and has proved a valuable im- 

 provement in the weaving art. The picker moves continually in a 

 straight line in the raceway of the lathe, obviating the use of the 

 common horizontal spindle, on which the picker runs, and it is also 

 much more easily taken out and put in, besides being less complicated 

 and expensive than the "picker in general use. This picker is made of 

 a rectangular form, to slide on the raceway freely in the shuttle-box. 

 It has an opening through the middle, through which passes the 

 picker-staff, driving the picker by moving reciprocally in a longitu- 

 dinal slot cut in the raceway of the shuttle-box. The picker-staff is 

 not secured to the picker, but merely has its upper end passing freely 

 through it, and a flange is secured on the top of the shuttle-box, pro- 

 jecting inwards, so as to prevent the picker from being raised up. 

 The picker-staff has a reciprocating motion from a pivot-axis below, 

 at its base, by which it is secured to a vertical standard attached to 

 the shuttle-box. The top of the picker-staff, therefore, describes con- 

 siderable arcs, but as it passes freely through the picker it moves in a 

 straight line with but little friction, especially since the ends of the 

 openings of the picker are made in a curved form, which allows the 

 picker-staff to roll in it, but yet to move the picker according to the 

 parallel motion of Watt. The picker-staff may even be dispensed 

 with, owing to the form of the picker, and a simple tenon secured to 

 the same by passing down and being connected with a central wag- 

 staff by a cord, may answer every purpose, in a more simple manner, 

 but with somewhat more friction. Scientific American. 



IMPROVED ENVELOPE MACHINERY. 



ONE million of envelopes are daily manufactured in the British 

 Islands. Each of these requires to be cut and folded with precision. 

 The former operation is performed partly by a patent cutting-machine, 

 and partly by means of a sort of large hollow chisel, the cutting part 

 of which is exactly the shape of the required envelope. The folding 

 was, till within a recent period, entirely done by manual labor, but 

 latterly by a folding machine, the invention of M. de la Rue. By 

 means of the admirable precision and rapidity of this engine, forty-two 

 envelopes can be folded in a minute. The machine consists of, 

 1. A table, or metallic surface, of the exact size of the envelope 

 which is laid on it, and which moves on a vertical plane. 2. A cor- 

 responding surface, called the box, which, descending on this table, 



