ICE 
ICE 
Spirit of wine makes no impression on this 
substance, but it dissolves in ether and 
linseed oil, or in nut oil digested gently in a 
sand bath : there are also other fat and oily 
substances which affect it very sensibly. 
The Chinese have been long acquainted 
with the art of dissolving it, and of giving 
it various colours. 
JAUNDICE. See Medicine. 
JAY, in ornithology, the variegated eor- 
vus, with the covering feathers of the wings 
blue, variegated with black and white. See 
Corvus. 
IBERIS, in botany, dandy-tuft, a ge- 
nus of the Tetradynamia Siliculosa class 
and order. Natural order of Siliquosae, or 
Cruciformes. Cruciferae, Jussieu. Essen- 
tial character: corolla irregular, with the 
outer petals larger ; sllicle emarginate, 
many-seeded. There are fourteen species, 
IBEX, in zoology, an animal of the goat 
kind, witli extremely long nodose horns, 
which bend backwards, and are of a black- 
ish colour, and annulated on the surface. 
The body is of a dark dusky colour, and is 
less in proportion to the height than that of 
the common goat: it has a great resem- 
blance to the deer kind ; the legs are also 
perfectly like those of the deer, straight, 
elegant, and slender. It is frequent in 
many parts of Europe, and, notwithstanding 
its vast horns, runs and leaps with surpris- 
ing force and agility. See Capra. 
ICE, water in the solid state. When 
, water is exposed to a diminished tempera- 
ture, it assumes the solid state, by shooting 
into crystals which cross each other in an- 
gles of 60 degrees. During this process of 
solidification, the temperature remains con- 
stant, being 32 degrees of the scale of Fah- 
renheit. See Caloric ; also Freezing. 
During congelation most of the gasiform 
fluids, which may have been contained in 
the water, are separated in the elastic 
form, and exhibit bubbles in the ice, unless 
the congelation may have been gradually 
effected from the bottom, or one of the 
sides ; in which case the bubbles are driven 
out, and the ice is much clearer. 
Ice is considerably lighter than water, 
namely, about one-eighth part; and this 
increase of dimensions is acquired with pro- 
digious force, sufficient to burst the strong- 
est iron vessels, and even pieces of artil- 
lery. It does not arise from the extrication 
of the gases ; for the refractive power of 
ice is less than that of water, as Dr. Hook 
long ago shewed, and has since been con- 
firmed by Wollaston. 
M. Provost observes, that congelation 
takes place much more suddenly than the 
opposite process of liquefaction ; and that, 
of course, the same quantity of heat must 
be more rapidly extricated in freezing, than 
it is absorbed in thawing; that the heat thus 
extricated being disposed to fly off in all 
directions, and little of it being retained by 
the neighbouring bodies, more heat is lost 
than is gained by the alternation : so that 
whei;e ice has once been formed, its pro- 
duction is in this manner redoubled. This 
circumstance must occur wherever it freezes, 
that is, on shore, in latitudes above 35 de- 
grees ; and it appears, from 30 degrees to 
the pole, the land is somewhat colder than 
the sea, and the more as it is farther distant 
from it ; and nearer the equator the land is 
warmer than the sea : but the process of 
congelation cannot, by any means, be the 
principal cause of the difference, and it is 
probable that the different capacity of earth 
and water for heat is materially concerned 
in it. 
Since the atmosphere is very little heat- 
' ed by the passage of the sun’s rays through 
it, it is naturally colder than the earth’s sur- 
face ; and for this reason, the most elevated 
tracts of laud, which are the most promi- 
nent, and the most exposed to the effects 
of the atmosphere, are always colder than 
situations nearer the level of the sea. 
The northern hemisphere is somewhat 
warmer than the southern, perhaps because 
of the greater proportion of land that it 
contains, and also in some measure on ac- 
count of the greater length of its summer 
than that of the southern ; for although, as 
it was long ago observed by Simpson, the 
different distance of the sun compensates 
precisely for the different velocity of the 
earth in its orbit, with respect to the whole 
quantity of heat received on either side of 
the equinoctial points, yet M. Prevost has 
shown, that in all probability, the same 
quantity of heat must produce a greater ef- 
fect when it is more slowly applied ; be- 
cause the portion lost by radiation from the 
heated body is greater, as the temperature 
is higher. Since, therefore, on account of 
the excentricity of -the earth’s orbit, the 
north pole is turned towards the sun seven 
or eight days longer than the south pole, 
the northern winters must be milder than 
the southern ; yet the southern summers, 
though shorter, ought to be somewhat 
warmer than the northern ; but, in fact, 
they are colder, partly perhaps from the 
much greater -proportion of sea, which, in 
