Oct. 19, 1882J 



NATURE 



603 



minium in the first instance with a considerable amount 

 of sulphuric acid. This gave us a mixture which, on 

 analysis, was found to contain 185 per cent, of sulphate 

 of lead. This mixture, when submitted to the reducing 

 action of a current yielded a mass of spongy lead that 

 contained only a mere trace of sulphate. 



As it seemed desirable fully to establish the fact that 

 the sulphate of lead formed on the discharge of a 

 cell is reduced in the subsequent charging, we took the 

 quondam lead plate of a fully discharged cell, determined 

 the proportion of sulphate to unaltered spongy lead, and 

 submitted it to the reducing action of a current. The 

 amount of sulphate on the plate before passing the cur- 

 rent was found to be 51 per cent., but, after the passage 

 of a current, of about an ampere for 60 hours, not a trace 

 of it remained. 



Hence it may be concluded that, during the alternate 

 discharging and re-charging of a Plants or Faure cell, 

 sulphate of lead is alternately formed and reduced on the 

 lead plate, and that the plate itself is not seriously cor- 

 roded. It would, however, appear desirable not to allow 

 the whole of the spongy lead to be reduced to sulphate 

 during the discharge, for two reasons, viz. : (1) because 

 the supporting plate stands a chance of being itself acted 

 on if there is not a sufficient excess of spongy metal ; and 

 (2) because the presence of this excess tends to facilitate 

 the reduction of the sulphate. 



We have already shown that sulphate of lead is pro- 

 duced by the local action that takes place between the 

 peroxide and its supporting lead plate during repose. The 

 same local action also takes place during the charging of 

 the plate, as was pointed out in our second communica- 

 tion, and this sulphate is, in its turn, attacked by the 

 electrolytic oxygen. In this way the absorption of oxygen 

 in forming the negative plate ought never to come to an 

 end. In order to see whether this was the case, we 

 allowed an experiment to continue for 115 hours, although 

 the main action was over in about forty hours. For the 

 last two days of the experiment, the amount of oxygen 

 absorbed was pretty constant, being about 9 c c. per 

 hour, which is equivalent to 024 grms. of sulphate of lead 

 formed and oxidated. The whole charge on the plate 

 was forty grms. of peroxide. This local action also takes 

 place during the discharge, as is evidenced by the sulphate 

 of lead formed on the negative plate always exceeding in 

 amount that formed on the positive plate. 



Through this local action taking place during the for- 

 mation of the cell, during repose, and during the dis- 

 charge, the lead plate which supports the peroxide must 

 be continually corroded more and more ; and it is 

 probably due to the insolubility of the sulphate formed 

 that the destruction of this kind of secondary battery 

 is so materially retarded in practice. 



J. H. Gladstone 

 Alfred Tribe 



T 



REFLECTIONS ON READING "DEGENERA- 

 TION": AN ESS A Y, BY E. R. L., F.R.S. 



'HE Ascidian came down like a wolf on the fold 



In the ages ere Earth had grown wrinkled and old, 

 He peered through the waves with his cerebral eye, 

 Frisked his tail, and dashed after the innocent fry. 



Like the leaves of the forest when Summer is green 

 That gay host of youthful Ascidians was seen, 

 Like the leaves of the forest when Autumn has blown 

 Their helpless descendants lie glued to a stone. 



For the Angel of Darwin came, gentle and bland, 

 And lapped them in comfort and fed them by hand, 

 And their eye myelonic waxed useless and blind, 

 And their caudal appendage was cut off behind. 



And there lies the sea-squirt with gill-slits all wide 

 And through them there eddies the nutritive tide, 

 Half mollusc, half vertebrate, solve him who can, 

 A riddle, a lesson for curious Man. 



J. H. P. 



ILLUSTRA TIONS OF NE W OR RARE ANIMALS 

 IN THE ZOOLOGICAL SOCIETY'S LIVING 

 COLLECTION 1 



IX. 

 23. 'pHE PIGMY HOG {Poratla salvania).— Few 

 A additions to the Zoological Society's living col- 

 lection of late years have attracted more attention than 

 the Pigmy Hogs of Nepaul, of which the first specimens 

 ever imported into Europe reached the Gardens in May 

 last. 



For our first knowledge of the existence of this diminu- 

 tive form of the pig-family in the sub-Himalayan forests 

 we are indebted to the researches of Mr. Bryan H. 

 Hodgson, formerly Resident at the Court of Nepaul, who 

 described the Pigmy Hog so long ago as 1847, in an 

 article published in the Journal of the Asiatic Society ot 

 Bengal. He named it Porcula salvania, from the forest 

 of Saul trees {Shorea robusta), in which it is chiefly 

 found. While the Wild Boar, or a species closely resem- 

 bling it abounds all over India, the Pigmy Hog is exclu- 

 sively confined, as Mr. Hodgson tells us, to the deep 

 recesses of the primeval forests of the Terai of Nepaul 

 and Bhotan, where it roams about in herds. It is very 

 rarely seen even by the natives. A well-known hunter 

 informed Mr. Hodgson that during fifty years' abode in 

 the Saul forests he had obtained but three or four of these 

 animals to eat, partly owing to their scarcity, and partly 

 to the speed with which the females and young disperse, 

 and to the extraordinary vigour and activity with which 

 the males defend themselves while their families are 

 retreating. Dr. Jerdon in his volume on the Mammals 

 of India, tells us that the full grown males live constantly 

 with the herd, which consists from five to twenty indi- 

 viduals, and are its habitual and resolute defenders 

 against harm. These animals feed principally upon roots 

 and bulbs, but also devour birds' nests, eggs, insects, and 

 reptiles. The female has a litter of fi otn three to four young 

 ones. Dr. Jerdon adds, that whilst at Darjeeling, he in 

 vain endeavoured to procure a specimen of it from the 

 Sikkim Terai, and Sir Joseph Fayrer, who hunted many 

 years in the Terai, was also unsuccessful in meeting with 

 the Pigmy Hog. 



Under these circumstances, it will be readily under- 

 stood that the authorities of the Society have been much 

 pleased at the recent acquisition of a small herd of these 

 animals, consisting of a male and three females, of one 

 of which we give an illustration (Fig. 23). They were 

 obtained in the Western Dooars of Bhootan after vast 

 trouble and expense, and were brought to England by 

 Mr. B. H. Carew, who has parted with them to the 

 Society. They were caught by Mr. Carew's hunters in 

 snares which were set for them in hundreds, over a range 

 of country twenty miles in extent. Though on their first 

 arrival they were very wild, they are already becoming 

 tame and confidential, and are, it is hoped, likely to 

 breed. 



In its general appearance the Pigmy Hog is not unlike 

 a small variety of the common boar, but measures only 

 about I foot 2 inches in length, and has but a very small 

 tail. The colour is a nearly uniform brown, slightly 

 shaded with dirty amber. The coat of hair is thin, 

 except upon the back. The Pigmy Hogs will be found 

 by visitors to the Zoological Society's Gardens in what is 

 usually called the Ostrich House, just beyond the Zebra 

 House, where a compartment has been specially fitted up 

 for their accommodation. 



1 Continued from p. 134. 



