M U C 
M U C 
23 L 
M O U 
the argillaceous part, or between it and the 
limestone. 
Confused mountains consist of stones heap- 
ed together without order, their interstices 
tilled with clay, sand, and mica. They 
scarcely ever contain any ore. 
Besides these, there are many mountains ' 
in different parts of the world, which derive 
their origin from volcanoes; but of these it; 
will be necessary to treat in a succeeding 
article. 
The height of mountains is usually calcu- 
lated by means of the barometer. For this 
purpose two columns of mercury, or baro- 
meters, are provided, and one is kept at the 
foot of the mountain while the other is carried 
to its summit. The degree of heat, if not 
equal, is reduced by calculation to an equa- 
lity, and for this purpose a thermometer is 
attached to each of the barometers. The 
degree of heat to which botlj are reduced, is 
55°. if, however, either of the barometers 
stands at 30 inches, and tire annexed thermo- 
meter at 35°, no reduction is to be made in 
the degrees indicated by that barometer ; but 
if either of them is at 30°, and the thermo- 
meter below 55°, we must add the expansion 
tire mercury in the barometer would have 
experienced at the heat of 55°. If the heat 
should, on the contrary, be above 53°, we 
must abstract the degree of expansion which 
it gains by that heat. Every degree of Fah- 
renheit’s scale produces an expansion of 
00.304 of the barometrical inch, when the 
barometer is at 30 ; when, therefore, the 
thermometer is at 1 1° below or above 55°, we 
must add in the former, or subtract in the 
latter case, eleven times that number from 
the barometrical height. In the same man- 
ner it may be calculated, whatever is the 
height of the barometer. When this matter 
is ascertained, the height is easily found by 
comparing the twp barometers, and calculat- 
ing the density of the air in the higher regions 
according to the principles of geometrical 
progression. 
The highest mountains are those which are 
situated at or near the equator; and the 
Andes are generally allowed to be the high- 
est of these. Catopaxi, one of the Andes, 
which was measured by Ulloa and the 
French academicians, was found to be some 
miles above the level of the sea; whereas the 
highest point of the Alps is not above a mile 
and a half. Mount Caucasus approaches 
n arest to the height of the Andes, of any of 
the Asiatic mountains. The Peak of Tene- 
rit'f, which has been so much celebrated, is 
about a mile and a half in height. It is an ex- 
traordinary circumstance, that the moon, 
which is a body so much smaller than our 
earth, should have been thought to exceed it 
in the irregularities of its surface; some of 
the mountains in that planet being formerly 
supposed to exceed nine miles in height : 
but Dr. Herschel has proved that the highest 
of them is not equal to one mile. 
The line of congelation, or of perpetual frost, 
on mountains, is calculated at 15,400 feet, at 
or near the equator ; at the entrance of the 
temperate zone, at 13,428; on Teneriff, at 
1,000; in Auvergne (lat. 45) 6,740; with us 
(lat. 52) 5,740. On the Andes, vegetation 
ceases at 14, 697 feet ; and on the Alps, at 
9,585. The air is so dry in these elevated 
situations, that M. d’Arcet observed, that on 
the Pic de Midi, one of the Pyrenees, salt of 
tartar remained dry for an hour and a half, 
though it immediately moistened in the same 
temperature at the bottom of the mountain. 
MOUNTING, in military affairs, signi- 
fies going upon duty. Thus, mounting a 
breach, is running up to it ; mounting the 
guard, is going upon guard; and mounting 
tiie trenches, is going upon duty in the 
trenches; but mounting a cannon, mortar, 
&c. is the setting it on its carriage, or the 
raising its mouth. 
MOUSE. See Mus. 
MOU ITL See Anatomy. 
MUCILAGE, a glutinous matter obtained 
from vegetables, transparent and tasteless, 
soluble in water, but not in spirit of wine, it 
chieily consists of carbon, hydrogen, and a 
small quantity of oxygen. See Gluten. 
MUCILAGINOUS GLANDS. See Ana- 
tomy. 
MUCOR, in botany, a genus of the order 
of fungi, m the cryptogainia class of plants. 
The fungus has vesicular heads supported by 
footstalks. There are 17 British species: 
the most remarkable of which are: l.The 
sphairocephalus, or grey round-headed mu- 
cor, growing upon rotten wood, and some- 
times upon decayed plants and mosses. The 
stalks of this are generally black, about a line 
in height, bearing each at the top a spherical 
ball aoout the size of a pin’s beau ; its coat 
or rind is covered with a grey powder, and 
containing within a black or fuscous spongy 
down. The coat bursts with a ragged, irre- 
gular margin. 2. The lichenoides, or little, 
black, pin-headed mucor. This species grows 
in groups near to each other, in chasms of 
the barks of old trees, and upon old park- 
pales. The stalks are black, about two lines 
in height, bearing each a single head, some- 
times a double or treble one, of the size of 
mustard or poppy seeds, of a roundish figure 
at first, but when burst, often fiattish or trun- 
cated, and of a black colour. The internal 
powdered down is black, with a tinge of 
green. 3. The mucedo, or common grey 
mould, grows on bread, fruits, plants, and 
other substances, in a putrid state. It grows 
in clusters; the stalks a quarter of an inch 
high, pellucid, hollow, and cylindrical; sup- 
porting each a single globular head, at first 
transparent, afterwards dark - grey ; which 
bursts with elastic force, and ejects small 
round seeds discoverable by the microscope. 
4. The glaucus, or grey cluster-headed 
mould, is found on rotten apples, melons, 
and other fruits; as also upon decayed \tfood, 
and the stalks of wheat. These are of a pel- 
lucid grey colour; the stalks are generally 
single, supporting a spherical ball, which, 
when magnified, appears to be compounded 
of numerous, fine, moniliform, necklace-like 
radii. 5. The crustaceus, or fingered mould, 
is frequent upon corrupted food of various 
kinds. It is of a white aqueous, colour ; the 
stalks single, each supporting at the top four 
or five necklace-like radii, diverging from 
the same point or centre.. 6. The septicus, 
or yellow frothy mucor,.is found on the leaves 
of plants, such as ivy and beech, &c. some- 
times upon dry sticks, and frequently upon 
the tan or bark in hot-houses. It is of no cer- 
tain size or figure, but of a fine yellow colour, 
and a substance resembling at first cream 
beaten up into froth. In the space of 24 
hours it acquires a thin filmy coat, becomes 
dry, and full of a sooty powder adhering to 
downy threads. The seeds under the micro- 
scope appear to be globular Haller ranks 
it under a new genus, which hd terms fuligo ; 
the characters of which are, that the plants 
contained under it are suit, and like butter 
at first, but soon change into a black sooty 
powder. 
MUCOUS ACID. See Salactic acid. 
Mucous gland. See Anatomy. 
MUCUS, a fluid secreted by certain 
glands, and serving to lubricate many of the 
internal cavities of the body. In its natural 
state it is generally limpid and colourless; 
but from certain causes, will often assume a 
thick consistence and whitish colour like pus. 
As it is sometimes of very great importance 
in medicine to distinguish these tw>o fluids 
from each other, tiiis was lately proposed as 
the subject of a prize disputation by the 
iEsculapian Society of Edinburgh. The prize 
was gained by Mr. Charles Darwin, student 
of medicine from Litchfield.. 
The conclusions drawn from his experi- 
ments were, 1 . Pus and mucus are both so- 
luble in the vitriolic acid, though in very 
different proportions, pus being by far least 
soluble. 2. The addition of water to either 
of these compounds decomposes it.. The 
mucus thus separated either swims in the 
mixture, or forms large fiocculi in it; whereas 
the pus falls to the bottom, and forms, on. 
agitation, an uniform turbid mixture. 3.. Pus 
is diffusible through a diluted vitriolic acid, 
though mucus is not. The same also occurs 
with water, or with a solution of sea-salt, 
4. Nitrous acid dissolves both pus and mu- 
cus. Water added to the solution of pus 
produces a precipitate, and the fluid above 
becomes clear and green, w hile water and the 
solution of mucus form a turbid dirty-coloured 
fluid. 5. Alkaline lixivium dissolves, though 
sometimes w ith difficulty, mucus, and gene- 
rally pus. 6. Water precipitates pus from 
such a mixture, but does not mucus. 7. 
Where alkaline lixivium does not dissolve 
pus, it still distinguishes it from mucus, as it 
then prevents its diffusion through water. 
8. Coagulable lymph is neither soluble in 
concentrated nor diluted vitriolic acid. 9. 
Water produces no change on a solution of 
serum in alkaline lixivium, until after long 
standing, and then only a very slight sedi- 
ment appears. 10. Corrosive sublimate co- 
agulates mucus, but does not pus. 
From the above experiments, it appears 
that strong sulphuric acid and water, diluted 
sulphuric acid, and caustic alkaline- lixivium 
and water, will serve to distinguish pus from 
mucus; that the vitriolic acid can separate it 
from coagulable lymph, and alkaline lixivium 
from serum. Hence, w hen a person has any 
expectorated matter, the decomposition of 
which he wishes to ascertain, let him dissolve 
it in vitriolic acid, and in caustic alkaline 
lixivium; and let him add pure water to both, 
solutions. If there is a fair precipitation in 
each, he may be assured that some pus is 
present. But if there is a precipitation in 
neither, it is a certain test that the mixture is 
entirely mucus. If the matter cannot be 
made to dissolve in alkaline lixivium by time 
and trituration, we have also reason to believe 
that it is pus. 
Mucus, nasal: this name is given to ^ 
liquid which is secreted in the cavities of the 
nose, and is discharged outwardly, either by" 
the nostrils in the form of drops, or in that of 
masses more or less thick ; or by the fauqe# 
