i8o 



NATURE 



\_June 22, i! 



appear to have been strong, and it may be that some of 

 the light of some of the groups may be due to this 

 substance. 



Prof. A. Herschel and Dr. von Konkoly showed long 



ago that the spectra of the periodic meteors are different 

 for different swarms, and it does not seem surprising that 

 we have now a comet, the matter of the nucleus of which 

 under the sun's heat shows an essential chemical differ- 



ence from the long series of hydrocarbon comets which 

 have appeared since 1S64. 



Mr. Hind has kindly furnished me with the distance of 

 this comet from the sun at the time the photograph was 



taken. The comet was then 42,380,000 miles distant from 

 the sun, while the comet of last year was 69,420,000 miles 

 when I obtained the photograph of its spectrum. 



William Huggins 



KABATH'S ELECTRIC ACCUMULATORS 



AT intervals since the introduction of accumulators or 

 secondary batteries by M. Gaston Plantd, various 

 modifications have been made with a view to constructing 

 cells on a commercial scale. The most renowned of 

 these modifications was that of Faure, who applied red 

 lead to the surface of the lead plates, so as to furni-.h 

 a greater thickness of the spongy mass that is the effective 

 agent in the storage process. In this development he had 

 been anticipated by d'Arsonval, who sought to increase 



the efficacy of the oxidised lead electrode by covering it 

 with a layer of lead dross. De Meritens, Tommasi, and 

 others have worked in another direction by employing 

 many sheets of lead foil presenting a large amount of 

 surface, whilst Swan, Sillon, and Volckmar have taken 

 another departure in applying perforated plates of lead 

 with disintegrated material packed into the interstices. 

 From our contemporary La Nature we have borrowed 

 the accompanying illustration of another form of accumu- 

 lator due to M. Nicolas de Kabath, whose suggestion is 



=*=- ^^ 



Kabath's Accumulat rs made of c 



Fig. 5, Labjratory Accumulator. 



Fig. 4. Co 



to employ thin plates of gauffered or corrugated lead, 

 so as to secure a large amount of effective surface. The 

 thin corrugated sheets are cut into narrow strips and 

 packed between two stouter sheets of lead pierced 

 with holes, through which the dilute acid liquor can 

 circulate freely. The details of construction will be 

 amply explained by the figures. The object of the per- 

 forated exterior is to prevent the cells from becoming 

 short circuited by the possible falling down of the thin 



corrugated strips which are rapidly disintegrated during 

 the preliminary charging or " formation " of the cell. The 

 perforated leaden cases are themselves placed side by 

 side in an appropriate cell, and are connected so thr.t 

 they serve alternately as positive and negative plate;. 

 Smaller cells arc used for laboratory work. No detai.s 

 have yet been published, so far as we are aware, of their 

 performances or capability of retaining the charge that 

 has been imparted. 



