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appreciable loss into electric light or mechanical work. How, then, is a 
Faure’s box a better store of electric energy than a little Daniell’s cell P This 
question has precisely the same answer as “ Why is a pinch of dry gunpow- 
der better than a pinch of wet P ” Not because the dry gunpowder has more 
energy in it than the wet, but because the energy stored up in the dry gun- 
powder can be all, if we wish, used up quickly, and an explosion produced, 
whereas that in the wet can only be utilized bit by bit. So seven Faure’s 
boxes will illuminate one hundred Swan lamps for six hours, while seven 
Daniell’s cells, or, indeed, twice that number, although possessing a store of 
power millions of times as great as that in Faure’s boxes, will not illuminate 
a single Swan light. 
‘ But while fully recognizing the great advance made in the subject by 
Plante, and the recent improvements introduced by Faure, I do not wish to 
give the impression that the problem is by any means completely solved, 
since, if the attempt that Mr. Perry and myself, no doubt like many other 
electricians, are making to convert at a low temperature the energy in coal 
into electric energy, meets with even a fairly satisfactory solution, then a 
fragment of coal, or, it may be, a puff of gas rich in carbon or carbonic oxide, 
will be a practical store of energy of incomparably greater value than any 
secondary* battery. w . E Aybion . 
1 The City and Guilds of London Technical College , 
1 Finsbury , June 13.’ 
Globe Lightning. — M. Trecul records that on August 25, 1880, during a 
thunder-storm in the day-time, he saw a very brilliant, luminous body issue 
from a dark cloud. It was nearly white, having only a slight yellowish 
tinge, was distinctly circumscribed, slightly elongated in form, and had the 
appearance of being 35-40 centims. long and about 25 centims. wide. The 
two ends were somewhat conical. This body was visible only for a few 
moments, when it disappeared seemingly by entering again into the cloud, 
but before its disappearance, it threw off a small quantity of its substance, 
which fell vertically like a heavy body, leaving behind it a luminous train, at 
the edges of which were reddish sparks, or rather globules, for their light 
was not radiant. The upper part of the train became sinuous. The little 
falling body divided and soon afterwards became extinguished just before it 
passed down behind the houses. No sound was heard, although the cloud 
was not distant. ( Comptes Rendus, 28th March, 1881.) 
The Speed of Thought. — It is not unusual to hear the expressions, ‘ quick 
as thought ’ and 1 quick as lightning,’ used as if they were synonymous ; but 
there is a vast difference, comparatively speaking, between them. The 
electric impulse is practically instantaneous over, say, a mile of wire ; but, 
if we may trust the experiments of Helmholtz and others, the wave of 
thought requires about a minute to traverse a mile of nerve. An electric 
shock is felt simultaneously in every part of the body, but the sensations of 
touch and of pain occupy an appreciable time in making their impressions 
on the sensorium. The interval between the reception of an impression by 
the brain, and its perception by that organ, is, doubtless, inexpressibly 
short ; but as we can only test the speed of thought by noting the time 
elapsing between the application of the cause of the thought and the 
