HOR 
portion of gelatine, with a small part of 
phosphate of lime. The fixed alkalies rea- 
dily and totally dissolve horn into a yellow 
saponaceous liquor. 
Hern and tortoise-shell are applied to 
mechanical purposes, which require them 
to be bent and united in various ways ; this 
is performed by the aid of heat, applied 
either dry, with wanned irons or burning 
charcoal ; or, by softening the horn in boil- 
ing water, or in a weak solution of alkali: 
when thus softened, they will easily adhere. 
Mr. Aiken gives the following process for 
making the horn-ring that surrounds a com- 
mon opera-glass: “Aflat piece of horn is 
cut out, of the requisite shape, the ends to 
be joined are thinned down by a file, the 
piece is then put into boiling water till suf- 
ficiently supple, and is then rolled round a 
warm iron cylinder, and held in that posi- 
tion by a vice, so that the ends over-lap 
each other : another piece of iron, heated 
and grooved, is then laid upon the seam of 
the joined ends, and pressed upon the cy- 
linder, and there confined by an iron wire ; 
and the heat of the two, partially melts that 
portion of the horn, and cements the ends 
so completely, that no seam or joining can 
be observed when cold.” For the manner 
of making horn to imitate tortoise-shell, see 
Comb. 
Horn is also a musical instrument of the 
wind-kind, chiefly used in hunting, to ani- 
mate the hunters and the dogs, and to call 
the latter together. 
The French horn is bent into a circle, and 
goes two or three times round, growing 
gradually bigger and wider towards the 
end, which in some horns is nine or ten 
inches over. 
Horns of insects, the slender oblong 
bodies projected from the heads of those 
animals, and otherwise called antennae, or 
feelers. The horns of insects are extreme- 
ly various; some being forked, others plu- 
mose or feathered, cylindrical, tapering, 
articulated, & c. As to the use of these 
parts, some have imagined they served to 
wipe and defend the eyes ; others, that 
they served as feelers, lest the creature 
should run against any thing that might 
hurt it ; and others there are, who think 
them the organs of smelling. 
Horn ore, in mineralogy, is one of the 
species of silver ore ; its most frequent co- 
lour is pearl- grey, of all degrees of inten- 
sity, which borders sometimes on milk- 
white, and sometimes approaches to laven- 
der and violet-blue. It passes also, though 
HOR 
but rarely, into green. It is found massive, 
disseminated in thick membranes, in round- 
ish hollow balls ; also crystallized : specific 
gravity 4.8. When heated on charcoal be- 
fore the blow-pipe, it melts quickly, and 
leaves a globule of silver; it is even fusible 
by the flame of a candle ; it takes a polish 
by friction ; and its constituent parts, ac- 
cording to Klaproth, are 
Silver 
Muriatic acid 
Sulphuric acid 
Oxide of iron 
Alumina 
Lime 
97.00 
Loss 
100.00 
It occurs in veins, and generally in their 
upper parts, and is usually accompanied 
with brown iron ochre, and with silver 
glance, but seldom with native silver and 
red silver ore. It occurs in considerable 
abundance in the mines of South America, 
in some parts of France, and in Hungary. 
It derives its name from its property of cut- 
ting like horn ; and is, of course, soft, flex- 
ible, and ductile, when obtained in thin 
plates. 
Horn stone, or Horn steen, in minera- 
logy, a species of the flint genus, divided by 
Werner into three sub-species: the splin- 
tery, the conchoidal, and the wood-stone. 
The most common colour of the splintery 
horn-stone is grey ; it is found in veins, in y 
the shape of balls, in lime-stone, and form- 
ing the basis of porphyry, in several parts 
of Germany, and also in the Shetland 
islands. It appears to differ from quartz in 
containing a greater proportion of alumina ; 
when it contains a very large quantity, it 
passes into jasper. It sometimes borders 
on chalcedony and flint. The best mill- 
stone, called French burr, is cellular-splin- 
ter hornstone. Conchoidal hornstone oc- 
curs in beds, accompanied with agate, and 
is distinguished from the splintery by the 
lightness of its colours, its fracture, and its 
inferior translucency and hardness. 
In the woodstone several colours occur 
together, and it commonly exhibits colour- 
ed delineations, as clouded and striped, and 
these arrange themselves in the direction of 
the original woody texture. Its shape is 
exactly conformable to its former woody 
shape, so that it occurs in the form of trunk, 
branches, and roots. It is found in sandy 
