Professor Owen on the Megatherium. 91 
Two pieces of charcoal, one of which is less heated than the 
other by the flame, deport themselves exactly as a pair of plati- 
num wires under the same circumstances. Silver, copper, brass, 
and zinc, have also been examined, all of which exhibited the 
same electrical deportment as platinum when brought into con- 
tact with heated aur. re 
he following conclusions are drawn from the experiments 
above described :— 
1, Gaseous bodies which have been rendered conductible by 
strong heating, are capable of exciting other conductors, solid as 
well as gaseous, electrically. 
2. When a thermo-electric circuit is formed of air, hydrogen or 
carburetted hydrogen, alcohol vapor, charcoal, or finally a metal, 
whether combustible or incombustible, an electric current is de- 
veloped, which proceeds from the hottest place of contact through 
the air to the less warm place. 
3. The development of electricity which has been observed in 
processes of combustion, and particularly in flame, is due to ther- 
mo-electric excitation, and stands in no immediate connection 
with the chemical process. 
4. The products.of combustion do not therefore by any means 
occupy the relation ‘te, the burning body which has been assumed 
by Pouillet ; ifspositive electricity rises with the ascending gases, 
itis only in. t degree in which the burning body and the air 
exterior to the place of combustion, or rather exterior to the place 
of hottest contact, are connected by a proper conductor. 
< 
_——— 
il 
‘ XVII.—Comparison of the modifications of ‘the Osseous 
structure of the Megatharium with that in other known exist- 
mg and extinct species of the class Mammalia: being an ab- — 
Stract of a Memoir read by Professor Owen, to the Royal So- 
ciety of London.* 
Havine completed the description of the skeleton of the Me- 
ium, which was illustrated by an extensive series of accu- 
rate and highly finished drawings, the Professor compares the 
modifications of the osseous structure of this gigantic extinct 
animal, with that in other known existing and extinct species 
the class Mammalia, in the following terms :— 
other known existing and extinct species 6f Mammalia.—The 
teeth agree in aaenen, kind, mode of implantation and growth, 
With those of the sloth, and their structure is a modification of 
that peculiar to the sloth tribe. All the modifications of the 
geese * Cited from Jameson’s Edinb. Jour., li, 350, 
Sseous Structure of the Megatherium, cones with that in — 
J 
