584 
NATURE 
[April 19, 1883 
supposed that this hydrogen compound may play an im- 
portant. part in the subsequent production of electro- 
motive force. It therefore appeared desirable to obtain 
experimental evidence as to whether hydrogen is so 
absorbed. The process we adopted for this purpose was 
founded upon the observation of Graham that hydrogen 
associated with palladium reduced ferri- to ferro-cyanide 
of potassium, and that generally in the occluded condition 
the element was mure active chemically. We had pre- 
viously ascertained that hydrogen associated with other 
elements, as platinum, copper, and carbon, was capable 
of reducing potassium chlorate to chloride, This method 
seemed to give trustworthy results, and therefore we 
applied it in this instance. As the result of several trials, 
however, we found that the amount of hydrogen asso- 
ciated with the reduced lead was almost inappreciable. 
Small as this quantity is, however, it is by no means im- 
possible that it may be the cause of the exceedingly high 
electromotive force observed for the first few moments, on 
joining up a completely formed cell immediately after its 
removal from the circuit of the charging current. This, 
however, may be due, as Planté imagined, to the gaseous 
hydrogen itself. The principal if not the only function 
of the hydrogen of the water or sulphuric acid is there- 
fore that of reducing the lead compounds. 
By a totally different process Prof. Frankland has very 
recently come to the same conclusion as ourselves in 
regard to the exceedingly small amount of occluded 
hydrogen. 
3. Evolution of Oxygen from the Peroxide Plate.— 
Planté noticed a small escape of gas from the negative 
plate of his cell immediately after its removal from the 
influence of the charging current. This he attributed to 
a decomposition of water by means of local circuits be- 
tween the peroxide and the subjacent lead plate in contact 
with it. 
The explanation we gave in our first paper (NATURE, 
vol. xxv. p. 221) of the local action which goes on at the 
negative plate does not account for the escape of any gas 
—either oxygen or hydrogen. We therefore thought 
it of interest to ascertain the nature, and if possible the 
origin, of the gas noticed by Planté. 
We found that the escape of gas from a Planté nega- 
tive plate was very slight, and soon ceased; but we 
observed that it became much more pronounced when 
the temperature of the electrolytic liquid was raised. 
order to get a sufficient quantity of the gas for examina- 
tion, we prepared a negative plate according to the pro- | 
cedure of Faure, and then heated it in dilute acid, with 
an arrangement for collecting the gas as it was evolved. 
The amount of gas was still very small in comparison with 
that of the peroxide, but a sufficient quantity was col- 
lected to enable us to ascertain that it was oxygen. We 
next heated some of the electrolytic peroxide apart from 
the lead plate, and again noticed a similar evolution of 
gas, which was also found to be oxygen. This shows, 
therefore, that it was not a result of local action. 
The gas has generally some odour of ozone, and, on 
testing the dilute acid between the plates of a Planté cell, 
we always found traces of something that bleached per- 
manganate of potassium, and which might be either 
ozone or peroxide of hydrogen. 
The origin of the gas noticed by Planté may be easily 
attributed to the oxygen which always passes off in quantity 
from the peroxide plate during the process of “ formation.” 
It is only necessary to suppose that some of this becomes 
condensed on the peroxide, and is gradually eliminated 
from it when the surrounding conditions are changed. 
But the matter is capable of another explanation. If 
peroxide of hydrogen be really formed in the liquid, it 
will exert its well-known influence on higher oxides, 
namely, that of reducing them and itself at the same 
time. 
into peroxide of hydrogen oxygen is evolved. 
In | 
As a matter of fact, if peroxide of lead is dropped | 
| reader to judge for himself. 
4. Temperature and Local Action.—Planté has recently 
pointed out that an elevation of temperature facilitates 
the formation of his secondary cell (Comptes Rendus, 
August, 1882). The character of the chemical changes 
which took place at the negative plate led us to think it 
exceedingly probable that this increase in the rate of 
formation arose from an augmentation in the amount of 
local action. Experiment showed such to be the case, 
Pairs of similar negative plates on Planté’s model were 
allowed to remain in repose at 11° C. and 50° C. respec- 
tively, and the formation of the white sulphate was visibly 
more rapid at the higher than at the lower temperature. 
The same is also true with negative plates prepared by 
Faure’s process. Thus we found that two similar plates 
kept in repose for an hour, the one at 11° C. and the other 
at 50° C., formed by local action 2°6 and 7°4 per cent. of 
lead sulphate respectively. On two other plates the pro- 
portions were 7°6 and 9'5 per cent. respectively. These 
observations of course by no means exclude the idea 
that an increase of temperature may facilitate the other 
chemical changes that take place in the formation of a 
lead and lead-oxide cell. J. H. GLADSTONE 
ALFRED TRIBE 
THE LION AT REST 
Be illustration which we give on next page, from Za 
Nature, is after a photograph of one of the lions 
in the Zoological Gardens, London. This photograph 
may be regarded as one of the numerous triumphs of 
instantaneous photography, valuable both to art and 
Science. The original was rephotographed in Paris 
directly on wood, by means of a special collodion, at 
present much used. This has assured a_ perfectly 
faithful reproduction of the original, exhibiting all the 
characteristic details of the lion at rest. The illustration 
tells its own story. 
ON THE RELATIONS OF THE FIG AND THE 
CAPRIFIG? 
HE relations of the fig and the caprifig, or the cultivated 
varieties of fig and the wild form of the Mediterranean 
region, have been variously explained by different writers, 
including those recent ones whose works are cited below. 
Intimately connected with this question is the process of 
| caprification, so often and so circumstantially described 
by ancient and modern authors, amongst the later of 
whom we may mention Gasparrini. Graf Solms-Laubach’s 
essay is an elaborate work of upwards of one hundred 
quarto pages, embodying the results of much research. 
Not the least interesting part is that treating of caprifica- 
tion, or perhaps we might say the manner in which fer- 
tilisation is effected. The author regards the cultivated 
edible varieties of fig as constituting one race, and the 
wild caprifig as another race of one and the same species; 
and the former as having developed from the latter under 
the influences of cultivation. Gasparrini, on the con- 
trary, described them as distinct genera. Dr. Fritz Miller 
takes an altogether different view. He says it appears to 
him far more likely that the fig and caprifig represent, as 
Linnzus supposed, different forms, the male and the 
female, belonging together, and not proceeding the one 
from the other, but which developed side by side, before 
any cultivation, through natural selection. An examina- 
tion of the facts adduced by Solms-Laubach himself 
seems to point to the correctness of Miller's view. But 
we will set them forth as briefly as possible, leaving the 
The responsibility of their 
accuracy rests with the author whom we are quoting. It 
= «Die Herkunft, Domestication und Verbreitung des gewéhnlichen 
Feigenbaums (Ficus Carica, L.).’’ Von Grafen 2u Solms-Laubach. (Git- 
tingen, 1882.)—‘‘ Caprificus und Feigenbaum.” Von Fritz Miller. Aessros, 
xi. p. 30 
della Societa 
Sulla Caprificazione, &c.'? G. Arcangeli. Processi Verbali 
Toscana di Scienze Naturali, November, 1882. 
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