474 
its removal from the tomb and exposure to the air—proving 
that these lamps were not supplied from any bituminous 
source, or volcanic fire. He considers the requisites for 
an everburning lamp to be,—a perpetual wick, which 
might be made of gold wire, or asbestus; and a perpetual 
supply of fuel, which he imagines the bituminous springs 
of Pitchford, in Shropshire, or the inflammable gases is- 
suing from fissures in coal mines, would afford. That such 
could supply fuel for a flame, so long as the bituminous 
spring existed, or the gas continued to exhale from the 
mines, is evident; but itno more deserves the appellation of 
an everburning lamp, than does a fire arising from any 
voleanic source. ‘The desideratum for such a lamp is, that 
it should contain, within itself, a renovating principle, such 
as, probably, does the luminous atmosphere encompassing 
the body of the sun, supposed by Sir William Herschel 
to be electrical. , 
**That electricity was the principle upon which such a 
lamp could be constructed having occurred to me some 
years ago, I reflected upon the different means by which a 
constant light could be produced from this source, and 
concluded that, if by an arrangement of metals a thermo- 
electric current could be produced of sufficient intensity 
to decompose water, the heat produced by the burning of 
the two gases arising from the decomposition, would be suf- 
ficient, when applied to the alternate metallic junctions, to 
continue the electrical current of the thermo-electric pile; 
while the gases, which in burning become aqueous vapour, 
might be condensed by passing through a long tube, through 
which being conveyed to the closed vessel in which the 
water had been originally placed, they would again under- 
go decomposition, recombination, and condensation. Sucha 
thermo-electric arrangement has been discovered by Prof. 
Botto of Turin, who has obtained decomposition of water 
from a series composed of a great number of wires of 
