I N D 
I N D 
I N F 
u 
By giving out oxygen. Of course it owes its 
bine colour to that principle. This theory 
was first suggested by Mr. Haussman, and 
still farther confirmed by Berthollet. Now 
it is only when green that it is in a state en- 
able of being held in solution by lime, al- 
alies, &c. in which state it is applied as a 
dye to cloth. The cloth when dipt into the 
vat containing it thus dissolved, combines 
with it, and the blue colour is restored by ex- 
posure to the atmosphere. It may be re- 
stored equally by plunging the cloth into 
oxy-nmriatic acid. Hence the restoration 
cannot but be ascribed to oxygen. Hence, 
then, the reason that sulphurous acid, the ve- 
getable acids, sulphat of iron, give sulphat of 
indigo a green colour. 
From these experiments we see also that 
the colour of indigo is destroyed by the addi- 
tion of those substances which part with oxy- 
gen very readily, as the black oxide of man- 
ganese. In that case the indigo is destroyed, 
for its colour cannot be again restored. 
Nitric acid attacks indigo with great vio- 
lence, the evolution of abundance of heat, 
and nitrous gas. When of the specific gra- 
vity 1.52, it even sets fire to indigo. When 
the acid is diluted the indigo becomes brown, 
and crystals make their appearance, doubt- 
less consisting of oxalic acid. What remains 
behind is a brown viscid substance of a very 
bitter taste, probably analogous to the yellow 
bitter principle of Welter. 
Muriatic acid does not act upon indigo in 
its common state, but it readily dissolves in- 
digo precipitated from the sulphat, and forms 
a blue coloured solution. The same pheno- 
mena are exhibited by the phosphoric, acetic, 
tartaric acids, and probably l-.y all, except the 
acid supporters. 
Oxymuriatic acid destroys the colour of 
incHgo as readily as nitric acid, and obviously 
for the same reason. 
Indigo is not acted upon by alcohol, ether, 
nor oils. The two first solvents, indeed, ac- 
quire a yellow colour when digested on com- 
mon indigo by dissolving its resin. 
When indigo is mixed up with bran, woad, 
and other similar substances, which readily 
undergo fermentation, it assumes a green co- 
lour during the fermentation, and is then ea- 
sily dissolved by lime or potass. It is by this 
process that it is usually rendered proper for 
dyeing. 
When indigo is distilled, it yields products 
different from any other vegetable substance, 
if the accuracy of Bergman, who alone has 
made the experiment, is to be trusted. He 
distilled 576 grains in a small retort connect- 
ed with a pneumatic apparatus. He obtained 
the following products : 
19 grains carbonic acid gas 
173 of a yellow acid liquid, contain- 
ing ammonia 
53 oil 
331 charcoal 
■#76. 
INDIVISIBLES, in geometry, the ele- 
ments or principles into which any body or 
figure may be ultimately resolved; which' ele- 
ments are supposed infinitely small: thus a 
line may be said to consist of points, a sur- 
face of parallel lines', and a solid of parallel 
and similar surfaces ; and then, because each 
of these elements is supposed indivisible, if 
in any figure a line be drawn through the ele- 
ments perpendicularly, the number of points 
in that line will be the same as the number 
of the elements ; whence we may see that a 
parallelogram, prism, or cylinder, is resolva- 
ble into elements or indivisibles, all equal to 
each other, parallel and like to the base ; a 
triangle into lines parallel to the base, but de- 
creasing in arithmetical proportion ; and so 
are the circles which constitute the parabolic 
conoid, and those which constitute the plane 
of a circle, or surface of an isosceles cone. 
A cylinder may be resolved into cylindri- 
cal curve surfaces, having all the same height, 
and continually decreasing inwards, as the 
circles of the base do on which they insist. 
The method of indivisibles is only the an- 
t(ent method of exhaustions, a little disguised 
and contracted. It is found of great use in 
shortening mathematical demonstrations, of 
which take the following instance in the fa- 
mous proposition of Archimedes, viz. that a 
sphere is two-thirds of a cylinder circum- 
scribing it. 
Suppose a cylinder, a hemisphere, and an 
inverted cone (Plate Miscel. fig. 133) to have 
the same base and altitude, and to be cut by 
infinite planes all parallel to the base, of which 
dg is one. It is plain the square of dh will be 
every where equal to the square of kc (the ra- 
dius of the sphere) ; and consequently, since 
circles are to one another as the squares of the 
radii, all the circles of the hemisphere will be 
equal to all those of the cylinder, deducting 
thence all those of the cone : wherefore the 
cylinder, deducting the cone, is equal to the 
hemisphere ; but it is known that the cone is 
one-third of the cylinder, and consequently 
the sphere must be two-thirds of it. 
INDORSEMENT, in law, any thing 
written on the back of a deed, as a receipt for 
money received. See Bills of Exchange. 
INDUCEMENT, in law, what is alledg- 
ed as a motive or incitement to a thing, and 
is used specially in many cases ; as, there is 
an inducement in actions, to a traverse in 
pleadings, a fact or offence committed, &c. 
Inducements to actions need not have so 
much certainty as in other cases : a general 
indebitatus is not sufficient where it is the 
ground of the action ; but where it is the in- 
ducement to the action, as in consideration 
of forbearing a debt till such a day (for that 
the parties are agreed upon the debt), this 
being but a collateral promise, is good with- 
out shewing how due. 2 Mod. 70. An in- 
ducement to a traverse must be such matter 
as is good and justifiable in law. There is an 
inducement to a justification when what is 
all edged against it is not the substance of the 
plea. Moor. 847. 
INDUCTION, in law, is the giving a clerk 
instituted to a benefice the actual possession 
of the temporalities thereof, in the nature of 
livery of seisin. It is performed by a man- 
date from the bishop to the archdeacon, who 
commonly issues out a precept to some other 
clergyman to perform it for them ; which 
being done, the clergyman who inducts him 
indorses a certificate of his induction on the 
archdeacon's mandate, and they who were 
present testify the same under their hands, 
and by this the person inducted is in full and 
complete possession of all the temporalities of 
his church. 
INDULT, in the church of Rome, the 
R 2 
power of presenting to benefices granted to 
certain persons by the pope. Of this kind is 
the indult of kings and sovereign princes, in 
the Romish communion, and that of the par- 
liament of Paris granted by several popes. 
By the concordat for the abolition of the 
pragmatic sanction, made between Francis I. 
and Leo X. in 1516, the French king had the 
power of nominating to bishoprics, and other 
consistorial benefices,, within his realm. At 
the same time, by a particular bull, the pope 
granted him the privilege of nominating to 
the churches of Brittany and Provence. 
INERTIA of matter, in philosophy, is 
defined by sir Isaac Newton to be a passive 
principle by which bodies persist in their mo- 
tion or rest, receive motion in proportion to 
the force impressing it, and resist as much as 
they are resisted, it is also defined by the 
same author to be a power implanted in alt 
matter, whereby it resists any change endea- 
voured to be made in its state. See Me- 
chanics. 
INFAMY, which extends to forgery, per- 
jury, gross cheats, &c.. disables a man to be 
a witness or a juror ; but a pardon of crimes 
restores a person’s credit to make him a good 
evidence. 2 Haw. 432. 
INFANCY, management and diseases of. 
We have been induced to treat of those dis- 
orders which are peculiar to infancy sepa- 
rately from other affections, partly by the 
difference of character which such ailments 
assume from those of the adult periods of 
life, and partly by the opportunity the sub- 
ject will ali’ord of introducing some prelimi- 
nary observations on the management ot in- 
fants ; observations which we shall endeavour 
to make familiar and intelligible to the heads 
of families, or those engaged in conducting 
the hitman frame through its more tender and 
dependant states of existence. 
It would be altogether superfluous to urge 
the importance of this subject. It has been 
calculated that more than a fourth part of the 
human race die in the first year after birth ; 
and we have nearly the same evidence that 
this remarkable mortality originates not ia 
the unchangeable dispositions of nature, but 
principally from erroneous and perverted ma- 
nagement ! 
in the first division of this article we pro- 
pose, therefore, to suggest a few hints re- 
specting infantile diet ; the regulation of tem- 
perature, or external heat ; clothing ; air, and 
exercise. 
PART I. 
Sect. I. — Diet of infants. 
In the proper nourishment of children we 
are faithfully instructed by the almost unerr- 
ing counsels of nature. Where mothers are 
capable of suckling their offspring, this 
ought, in no instance, to be omitted : it is, 
indeed, equally a cause of astonishment and 
regret that such an obvious and important 
principle could at any time be neglected or 
questioned. “ See the infant (says a modern 
writer, while addressing himself to mothers) 
nourished by your fluids, and brought to a 
certain degree of perfection while yet in the 
womb. See him separated from it, and then 
see his nourishment flowing in another chan- 
nel. See the secretion and preparation of the 
milk, the increasing size of the breast, and 
