BMI 
(founts for the phenomenon of bine shadows, 
by the diminution of light ; having ob- 
served, that of two shadows which were 
cast upon a white wall, from an opaque 
foody illuminated by the moon, and by a 
candle at the same time, that which was en- 
lightened by the candle was reddish, and 
that which was enlightened by the moon 
was blue. However, the true cause of this 
appearance seems to be that assigned by 
M. Bougner, which agrees with the solution 
given of it about the same time by Mr. 
Melville. But, instead of attributing the 
different colours of the clouds, as Sir Isaac 
Newton does, to the different size of those 
globules into which the vapours are con- 
densed; Mr.Melvhle supposes, that the clouds 
only reflect and transmit the sun’s light ; and 
that, according to their different altitudes, 
they may assume all the variety ot colouis 
at sun-rising and setting, by barely reflecting 
the sun’s incident light, as they receive it 
through a shorter or longer tract of air : and 
the change produced in the sun’s rays by 
the quantity of air through which they pass, 
from white to yellow, from yellow to 
orange, and lastly to red, may be under- 
stood agreeably to this hypothesis, by ap- 
plying to the atmosphere what Sir Isaac 
Newton says concerning the colour of tran- 
sparent liquors in general, and that of the 
infusion of lignum nephriticum in parti- 
cular. 
BLUSHING, a suffusion or redness of 
the cheeks, excited by a sense of shame on 
account of a consciousness of some failing 
or imperfection. 
Blushing is supposed to be produced 
from a kind of consent or sympathy be- 
tween the several parts of the body, occa- 
sioned by the same nerve being extended to 
them all. Thus the fifth pair of nerves be- 
ing branched from the brain to the eye, 
ear, muscles of the lips, cheeks and palate, 
tongue and nose ; a thing seen or heard 
that is shameful aftects the cheeks with 
blushes, driving the blood into their minute 
vessels at the same time that it affects the 
eye and ear. Mr. Derham further observes, 
upon this subject, that a savory thing seen 
or smelt affects the glands and parts of the 
mouth ; if a thing heard be pleasing, it 
affects the muscles of the face with laughter ; 
if melancholy, it exerts itself on the glands 
of the eyes, and occasions weeping, &c. 
To the same cause is, by others, the pleasure 
of kissing ascribed. 
B MI, in music, the third note in the 
modern scale. 
BOA 
B MOLLARRE, or MolLe, one of the 
notes of the scale of music, usually called 
soft or flat, in opposition to b quadro. 
BOA, in natural history, a genus of ser- 
pents, of which the generic character is, 
plates on the belly and under the tail, with- 
a rattle. Gmelin mentions ten species only, 
but Dr. Shaw and others enumerate as 
many as eighteen. B. contortrix is found in 
Carolina, and has about 150 plates on the 
belly, and 40 on the tail ; it is broad with a 
convex back ; colour cinereous, with late- 
ral round spots; has a poisonous bag, but 
no fangs ; tail from one third to a hail the 
length of the whole body : it is very slow 
in its motions. B. constrictor, is very re- 
markable for its vast size, some of the prin- 
cipal species which are met with in India, 
Africa, and South America, have been seen 
between 30 and 40 feet long, and possessed 
of so much strength as to be able to kill 
cattle by twisting around them and crush- 
ing them to death by pressure, after which 
they devour them, eating till they are almost 
unable to move ; in that state they may be 
easily shot. Dr. Shaw observes that these 
gigantic serpents are become less common, 
in proportion to the increased population of 
the parts where they are found ; they are, 
however, still to be seen, and will approach 
the abodes in the vicinity of their residence. 
This species is beautifully variegated with 
rhombic spots; belly whitish; is of vast 
strength and size, measuring 30 and 36 feet 
long. With respect to age, sex, and climate, 
it is subject to considerable variations. It is 
supposed that an individual of this species 
once diffused terror and dismay in a whole 
Roman army, a fact alluded to by Livy in 
one of the books that have not come to us, 
but which is quoted by Valerius Maximus, 
in words to the following effect: “Since 
we are on the subject of uncommon pheno- 
mena, we may here mention the serpent so 
eloquently recorded by Livy, who says, 
that near the river Bagrada in Africa, a 
snake was seen of so enormous a magnitude 
as to prevent the army of Attilius Regulus 
from the use of the river ; and after snatch- 
in 0, up several soldiers with its enormous 
mouth and devouring them, and killing 
several more by striking and squeezing them 
with the spires Of its tail, was at length 
destroyed by assailing it with all the force 
of military engines and showeis ot stones, 
after it had withstood the attack of their 
spears and darts : that it was regarded by 
the whole army as a more formidable enemy 
than even Carthage itself; and that the 
