TRANSACTIONS OF SECTION G. 823 



The adoption of this system for the streets of every great city would effect an 

 economic revolution. There would be rapid communication between distant points 

 within the metropolitan areas; there would be rapid communication between 

 frequent stops for the convenience of local traffic and shopping ; the streets would 

 be brilliantly lighted by electricity; every bouse on the line would have access to 

 gas, steam, water, the telephone, telegraph, pneumatic tube, electric light, and 

 compressed aii' at will. Small industries would flourish because small and cheap 

 power from remote stations would be everywhere available, while the surface 

 of the streets could be maintained in a perfect state, with the minimum of cost, 

 and with complete immimity from disturbance other than for the repair of worn 

 surfaces. 



2. Transmission of Motion mid Power. By J. Walter Peabse. 



The flexible clutch is the first practical outcome of the mechanical combination 

 devised by M. R, Snyers, of Brussels, and described by the author in a paper on 

 the ' Communication of Motion between Bodies Moving at Diflerent Velocities ' 

 during the Manchester meeting of last year. While each of the fibres into which 

 the mass of one of the two bodies is split up acts separately and individually, 

 causing no shock on contact, their sum exerts a considerable mechanical eflbrt. 

 About a dozen flexible clutches and combined fast and loose pulleys are now in 

 operation, transmitting motion to dynamos, emery grinders, spinning machinery, 

 sewing machines, thus preventing that breakage of the beam or arm of the latter 

 which frequently occm-s on power being applied in the ordinary manner. The 

 amount of power transmitted is just that for which the clutch or pulley is calcu- 

 lated, the two parts slipping when that power is exceeded by the motor, or on an 

 excess of power being demanded by the machine, this property being useful in cases 

 of letting out power on hire. When, however, a clutch or pulley is of a maximum 

 capacity, any lower amount of power may be transmitted by regulating the degree 

 of penetration of the fibres between the corrugations of the other disc. Experience 

 shows that wear of the fibres, even when there is a considerable amount of slip, is 

 negligeable, the corrugated disc being made of softer material ; and this fact shows 

 the applicability of the principle to brakes of various kinds, which would exert a 

 retarding force equal to three or four times that employed to apply them, whereas 

 ordinary brake blocks never utilise more than 25 per cent, of the power exerted. 



I 



3. An Annual Winding Clock, luith Torsion Pendulum.^ 

 By W. H. Douglas. 



There is no change whatever in the wheel-work or main spring of an eight-day 

 lever clock except in the balance. The balance is removed, and in its place a lever 

 is fixed to the staff carrying the roller pin, which unlocks the lever escapement and 

 receives an impulse at each beat in the usual way, the additional lever imparting 

 impulse to a tooth attached to the pendulum, thus inducing torsion at each beat of 

 the clock. The regulating is effected by increasing the weight of pendulum to 

 make it lose, or decreasing the weight to make it gain ; it is also regulated by 

 means of a French sliding curb, moved by a screw to the right or left, as desired, to 

 make it go faster or slower without stopping the clock. 



The escapement may be described as a frictionless pendulum. The impulse, 

 given direct across the line of centres, as in the chronometer, is independent of oil, 

 and, becoming detached at each beat, the isochronal property of the pendulum is 

 not deranged by friction of any kind whatever. 



The cost of manufacture is precisely the same as in producing an eight-day 

 timepiece. 



' See Enffineerivg, vol. slvi. p. 413. 



