CATALOGUE. PHILOSOPIIT AND ARTS, PnACTlCAL MECHANICS. 183 



Lambert on the winch. N. Act. Helvet. I. 

 Kastner on the velocity of a crank or winch. 



N. C.Gott. 1774. V. 119. 

 Triple crank. Corn mill. Am. tr. 

 Alternate racks. LangsdorfFs hydr. PI. 32. 

 Fulton's patent cylinder for working pumps. 



E-epert. III. 220. 



A double screw. 

 Lauden's patent mode of moving pump rods. 



Repert. XII. 145. 

 Prony on converting rotatory into alternate 



motion. M. Inst. K. 216. 

 Cranks. Banks on machines. 46. 

 Jones on Wolff's equalised crank. Nich. VII. 



133. 



Nearly f csembling a fly in its effect. 

 R. B. Nich. IX. 212. 



The distance of two centres being 3, two levers move oa 

 them of which the lengths are 2 and 4 : the shorter sup- 

 ports a third of which the length is 5, receiving the end of 

 the longer in a joint at the distance 1 ; the motion of the 

 end will be initially almost rectilinear. 



The truth of this may be shown from the properties of 

 the ellipsis, and from the comparison of the sines of the 

 evanescent angles. But, more correctly, the length of the 

 second lever being to the same length increased by the 

 fhort portion of the third a« a; to 1 , the distance of the fixed 

 points must be to the same whole length as ix^Axx to 1. 

 Thus if aftz.8, as in the case proposed, the distance of the 

 fixed points must be to the whole length as .64 to 1 , and to 

 the short levei as .64 to .36 or as 16 to g, and not as 3 to 2. 



Wheelwork. 



Leup. Th. M. G. 1. 14. Belidor. Arch. Hydr. 

 I. i. 119. E. M. A. PI. III. Horlogerie. 

 E. M. A. VII. Art. Roiie. 



Particular kinds of Wheels. 



Hook's perfection of wheelwork. Animadv. 

 on Helvetius. 



Several wheels on the same axis. 



Bevilled wheels. Enc. Br. Art. Mechanics. 



Wheels without cogs. Nich. I. 328. 

 On lantern pinions. Nich I. 522i 546. 

 fKelly's instrument for bevilling wheels. 

 Repert. VI. 106. 



Says that the angles should be as the diameters of the 

 wheels : in reality the tangent of the angle must be to the 

 radius as one diameter to the other. 



Walking wheels. See application of force. 



When a strap runs on a revolving cone, and is sufficiently 

 tight, it advances towards the base of the cone, and does 

 not slide towards the point ; for the edge of the strap near- 

 est the base is drawn more rapidly than the other, and the 

 part advancing towards the wheel is bent towards the base. 

 Hence, in order that the strap may remain on the middle of 

 a wheel, it must consist of two portions of cones joined at 

 their bases, and if rounded, must be convex, not concave, 

 at its circumference, as may be seen in many manufacto- 

 ries. Y. 



Structure and Proportions of Wheels. 



Lahire on the teeth of wheels. A. P. IX. 90. 



283. 292. 

 *Camus on the teeth of wheels. A. P. 1733. 



117. H. 81. 

 Blakey's mode of drawing wire for pinions. 



Mach. A. VII. 255. 

 Gallonde's compass for wheelwork. Mach. 



A. VII. 315. 

 *Euler on the teeth of wheels. N. C. Petr. 



V. 299. XI. 207. 



A form without friction is perfectly impracticable, al- 

 though for a single tooth possible. 



Cutting engine for wheels, Emers. mech. f. 

 304. 



Lecerf on the proportion of wheels and pi- 

 nions. Ph. tr. 1778. 950. 



Kastner on the teeth of wheels. Commentat. 

 Gott. 1781. IV. M.S. 1782. V.M. 1. Dis- 

 sert. Math. 



*tEryC. Br. Suppl. Art. Machinery. 

 Imison's elements. I. 78. 



