TELLUBIUM. 
great and almost incurable unsoundness. See 
the article QuippIne.—Caries, though incom- 
parably rarer in the horse than in man, yet some- 
times occurs with such virulence as not only to 
destroy one tooth, but to communicate the rot- 
ting to neighbouring teeth and even to the jaw; 
and every carious tooth should be extracted,— 
not with the hammer and the punch, but with a 
keyed instrument similar to that used upon the 
human subject, but of a larger size. 
TELEPHIUM. See Onpine. 
TELLURIUM. A rare metal, discovered to- 
ward the close of last century. It occurs in its 
proper metallic state chiefly in combination with 
silver and gold. It has a lamellated texture, a 
strong metallic lustre, and a tin-white colour 
merging toward lead-grey. It is very brittle, 
fuses at a heat below redness, volatilizes at a red 
heat, and has a density of 6115. It ignites be- 
fore the blow-pipe, burns with a greenish-blue 
flame, and disappears in grey, pungent, inodor- 
ous fumes. An oxide is formed during combus- 
tion, possessing the properties of a grey colour, 
fusibility at a red heat, and violent decomposa- 
bleness before the blow-pipe. A soluble nitrate 
of the oxide results from the action of nitric acid 
upon the metal; and a volatile chloride, consti- 
tuting a white crystalline solid at common tem- 
peratures, is formed by passing chlorine over 
moderately heated tellurium. 
TELOPEA. A small genus of ornamental, 
exotic, ligneous plants, of the proteaceous order. 
The most showy species, 7’. spectosisstma, was in- 
troduced to Britain in 1789 from Australia; and 
is one of the most lovely evergreen shrubs of the 
greenhouse or the conservatory. It has com- 
monly a height of about 10 feet, and carries 
splendid scarlet-coloured flowers from May till 
July. Its habit of growth is firm and upright; 
and its general appearance, at all seasons, is hand- 
some and imposing. It loves a soil of sandy peat, 
and is propagated from cuttings; but it is very 
liable to perish from too great cold in winter, or 
from excess or deficiency of water at any season, 
or from other causes which assail it in common 
with other proteaceous plants,—and, in conse- 
quence, it occurs in comparatively few collec- 
tions, and is often found in a sickly state. 
TEMPERATURE. The subtle principle or 
imponderable fluid whose degrees and fluctua- 
tions constitute temperature, is noticed in the 
article Canoric; the instrument by which the 
scale, the intensities, and the changes of tem- 
perature are measured, is described in the arti- 
cle THERMOMETER; the part which temperature 
acts in the general phenomena of weather, is 
noticed in the article Murxoronogy ; the connex- 
ions which it sustains to the most conspicuous of 
particular meteorological phenomena, are pointed 
out in the articles Evaporation, CLoup, FREEz- 
ING, Hoar-Frost, Dew, and Ratn; the offices 
which it performs upon the constituents of the 
air, and the relations which it bears to their va- 
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TEMPERATURE. 
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415 
rious conditions, are mentioned in the article 
ATMOSPHERE; the control which it exercises 
over the aggregate adaptations of different zones 
and localities to the sustenance of organic exist- ° 
ence, is discussed in the article Crimatz; the 
part which it plays in the interior and vital eco- 
nomy of animals is described in the article Ant- 
MAL Heat; the offices which it serves in the 
exterior circumstances of animals, are mentioned 
in the articles Frepina or ANIMALS and SHELTER; 
the resistances which it makes to the healthy 
transmigration of any of the lower animals from 
their native region to a hotter or a colder one, 
are pointed out in the article AccLIMATATION OF 
Animaus; the relations which it sustains to dif- 
ferent latitudes of the globe and to different ele- 
vations above the level of the sea, and the deter- 
mination which it exercises over the geographical 
distribution of plants, are treated in the article 
AutitupE ; the offices which it performs upon 
plants, or the relations of stimulation, chemical 
action, growth, and resistance which it sustains 
to them, are noticed in the articles Organic 
CHEMISTRY, AGRICULTURAL CHEMISTRY, GERMINA- 
TIoN, Manure, SHELTER, BarK-Bep, Acciimata- 
TION OF Puants, and many others; the artificial 
raising and regulating of it in horticultural build- 
ings, are discussed in the articles HotHouss and 
GREENHOUSE; and the increasing and maintain- 
ing and modifying of it within the soil of fields, 
are pointed out in the articles Drarnine, Farm- 
Yarp Manure, and some others. Only three 
additional branches of the subject require to be 
discussed,—the general relations of temperature 
to the soil and to the meteorological conditions 
of the atmosphere,—the relations of the grasses 
to the temperature of different climates and of 
different years,—and the relations of exotic plants 
to the different temperatures of the soil and the 
air of gardens; and the second and the third of 
these are topics of great practical interest, to re- 
spectively the farmer and the gardener, and the 
first to all classes of persons whatever who are 
resident in the country; and we shall notice the 
second in the words of a writer in the 10th volume 
of the Quarterly Journal of Agriculture, and the 
third in those of a writer in the 13th volume of 
the Gardener’s Magazine. 
Humboldt, La Place, and many other modern 
philosophers, consider the fact of an internal heat 
in the earth as fully established, and they ascribe 
to it the origin and phenomena of volcanoes in 
connexion with metallic bodies, and with access 
of water to supply oxygen and hydrogen. At 8 
feet deep, the annual temperature varies only 
from 5° to 7°; and at 4 feet, from 10° to 12°; 
while at one foot it ranges from 19° to 20°,—and 
in the open air it varies from 50° to 60°. At the 
depth of about 40 or 50 feet, the temperature of 
the earth is the same in winter and summer, ap- 
parently colder in summer, and warmer in win- 
ter; and the earth is believed to increase in heat, 
a degree in every 15 or 20 yards depth. In the 
