ORE 
may be separated by the addition of an 
acid. 
“ Aiitinionial ores.” Dissolve a given 
weight in three or four parts of muriatic, 
and one of nitric acid. Tliis will take up 
the antimony, and leave the sulphur, if any. 
On dilution with water the oxide of anti- 
mony is precipitated, and the iron and mer- 
cury remain dissolved. Lead may be de- 
tected by sulphuric acid. 
“ Ores of cobalt” may be dissolved in 
nitro-muriatic acid. Then add carbonate 
of potash, which, at first, separates iron and 
arsenic. Filter, and add a further quantity 
of the carbonate, when a greyish-red preci- 
pitate will fail down, which is oxide of co- 
balt. The iron and arsenic may be sepa- 
rated by heat, which volatilizes the arsenic. 
Cobalt is also ascertained, if the solution of 
an ore in muriatic acid give a sympathetic 
iqk. See Klaproth’s Essays. 
To analyze ores in the dry way, a me- 
thod which atfords the most satisfactory 
evidence of their composition, and should 
always precede the working of large and 
extensive strata, a more complicated appa- 
ratus is required. An assaying furnace,with 
muffles, crucibles, &c. are absolutely neces- 
sary. See Assaying ; Laboratory, &c. 
The reduction of an ore requires fre- 
quently previous roasting, to expel the 
sulphur aud other volatile ingredients; or 
this may be effected by mixing the pow- 
dered ore with nitre, and projecting the 
mixture into a crucible. The sulphate of 
potash, thus formed, may be washed off, 
and the oxide inust be reserved for subse- 
quent experiments. As many of the me- 
tals retain their oxygen so forcibly, that the 
application of beat is incapable of expelling 
it, the addition of inflammable matter be- 
comes expedient. And, to enable the re- 
duced particles of metal to agglutinate and 
form a collected mass, instead of scattered 
grains, which would otiterwise happen, some 
ftisible ingredient must be added, through 
which, when in fusion, the reduced metal 
may descend, and be collected at the bot- 
tom of the crucible. Substances that an- 
swer both these purposes are called fluxes. 
The alkaline and earthy part of fluxes serve 
also another end; viz. that of combining 
with any acid which may be attached to a 
metal, and which would prevent its reduc- 
tion, if not separated. The ores of differ- 
ent metals, and different ores of the same 
metal, require dift'erent fluxes. See Fl.nx. 
The ore, after being roasted, if necessary, 
is to be well mixed with tliree or four times 
ORG 
its weight of the flux, and put into a cru- 
cible, with a little powdered charcoal over 
the surface. A cover must be luted on, 
and the crucible exposed to the necessary 
heat in a wind-furnace. Ores of iron, as 
being difficultly reduced, require a very in- 
tense fire. Those of silver and lead are 
metallized by a lower heat. The metal is 
found at the bottom of the crucible, in the 
form of a round button. Tlie volatile me- 
tals, as mercury, zinc, arsenic, tellurium, 
and osmium, it is obvious, ought not to be 
treated in the above manner, and require 
to be distilled with inflammable matters in 
an earthen retort. See Kirwan’s Minera- 
logy- 
ORGAN. Having, under tlie article 
Musical instruments, given a pretty full 
account of this instrument, we shall here 
only give a description, with figures, of the 
barrel-organ. See Plate I. Barret Organ, 
and Plate II. parts of ditto. 
The barrel-organ is generally portable, 
and is so contrived, that the same action of 
the hand, which turns the barrel, supplies 
the wind, by giving motion to the bellows ; 
it consists of three principal parts : 1, The 
pipes, by which the sound is produced. 
2. The bellows, supplying them with air. 
3. The barrel and keys, by which the pipes 
are sounded at proper intervals. The pipes 
are of two kinds, of metal and of wood : the 
wooden ones are a square trunk of deal 
wood, A B, (fig. 5) closed at one end by a 
plug of wood, D, and at the other by a 
piece of wood, E, containing a crooked 
passage to bring air to the pipe, through the 
short tube, F;\aisapiece of oak board, 
glued to the block, E, and hollowed out to 
communicate with the crooked passage in 
it, and leaving a small crack, between it and 
the edge of the block, E, through which the 
air issues in oqe continued stream ; in its 
passage it is divided by the edge of one side 
of the trunk. A, which is cut as sharp as 
possible for that purpose, and which is exact- 
ly in the same line witli the orifice whence 
the air is emitted. 
The sound is produced by the vibration 
of the air which is contained in the trunk, 
A, and by increasing or diminishing the 
length of the pipe, the tone is altered at 
pleasure to bring it to the proper note it is 
to perform when placed in the instniment: 
this is done by sliding the plug, D, up or 
down in the pipe. 
A metal pipe, a section of which is shown 
in fig. 6, is nearly the same in its operation, 
though different in its construction. It is a 
