882 KEPOET— 1887. 



experienced in the use of electric contacts may be overcome. If the parts are 

 made to touch even in the slightest degree a thoroughly good contact is instantly 

 secured. 



The method is applicable to signalling apparatus and many other purposes, and 

 is already used with success by the inventor in automatic machinery for reehng 

 silk from the cocoon. By its use contacts have worked reliably for very long 

 periods under circumstances which would give rise to insuperable difficulties 

 without it. 



Its application to automatic machinery for reeling silk from the cocoon was 

 explained. This machinery has created a new industry, all silk having hitherto 

 been reeled by hand. 



The use of electrical appliances for reeling silk is greatly facilitated by the 

 employment of this device and is leading to important results ; and the inventor 

 considers that, as by this means a perfectly reliable contact is easily obtained, the 

 use of electricity for coatroUing textile and other machinery may be very greatly 

 and advantageously extended, especially in all cases in which light contacts must 

 be used. 



6. A new Form of Secondary Battery. By Killingworth Hedges. 



This battery is of the Plants t^-pe and designed to obtain the maximum of 

 surface for the peroxide plate, while the total weight is much reduced and the 

 available electro-motive force is increased by using a strip of zinc for the positive 

 plate instead of lead as in all modifications of the Plants form. The peroxide plate 

 is constructed on M. Bailly's method, the main conductor ramifying throughout the 

 mass of the plate. A basket work of lead wool is tightly pressed into the space 

 left between a porous pot or plate and the outside receptacle of the battery, this 

 diaphragm oftering little resistance to the passage of the current as it is made of 

 compressed sand, and it prevents any possibility of short circuit with the positive or 

 reduced electrode. The current is led from the zinc plate by causing it and the 

 'connecting wire to dip in mercury ; this plan helps to keep up the amalgamation. 

 The lead-zinc battery is not new, but this is the first in wliich ordinary zinc has 

 been employed instead of lead or copper coated with ziuc electrolytically. The 

 action is as follows : — the zinc is attacked by the sulphuric acid in the presence of 

 the peroxide of lead, the latter acting as a perfect depolariser ; the reaction is much 

 more energetic than in a lead-lead couple, the available EMF being 2'5 volts. 

 In discharging, the zinc plate dissolves in the dilute acid, and the sulphate of zinc 

 formed is decomposed on re-charging, metallic zinc being deposited on the zinc 

 plate. Thus the zinc is never consumed but is only dissolved and re-deposited. The 

 external cells are made of very thin celluloid. A basket containing six of these 

 cells, each of 60 ampere-hour capacity, which will maintain six four-candle lamps 

 for over eight hours, weighs imder one hundredweight. The lamps were shown at 

 work.^ 



G. Underground Electrical Worli, in America. By F. Brewer. 



7. Imjirovements in Lifeloats. By J. T. Morris. 



8. Li7ilc Motion for Steam Engines. By J. M. McCulloch. 



9. On the Communication of Motion between bodies moving at different 

 Velocities. By J. Walter Pearse. 



This combination, devised by M. R. Suyers, of Brussels, is described by him as 

 the ' infinitesimal division of a mass into elastic elements and their dynamical in- 



» For illustration see Electrical Review, May 24, 1887. 



