DI V 
hardness. We shall now add some in- 
stances of the wonderful tenuity of certain 
bodies, which have been produced either 
by art, or discovered by means of micros- 
copical observations amongst the stupen- 
dous works of nature. 
The spinning of wool, silk, cotton, and 
such-like substances, affords no bad speci- 
mens of this sort ; since the thread winch 
has been produced by this means, has often 
been so very fine as almost to exceed the 
bounds of credibility, had it not been suf- 
ficiently well authenticated. Mr. Boyle 
mentions that two grains and a half of silk 
was spun into a thread 300 yards long. A 
few years ago, a lady of Lincolnshire spun 
a single pound of woollen yam into a thread 
of 168,000 yards long, which is equal to 
95 English miles. Also a single pound 
weight of fine cotton-yarn was lately spun, 
in the neighbourhood of Manchester, into 
a thread 134,400 yards long. 
The ductility of gold likewise furnishes 
a striking example of the great tenuity of 
matter amongst the productions of human 
ingenuity. A single grain weight of gold 
has been often extended into a surface 
equal to 60 square inches. If every square 
inch of it is divided into square particles 
of the hundredth part of an inch, which will 
be plainly visible to the naked eye, the 
number of those particles in one inch 
square, will be 10,000 ; and multiplying 
this number by the 50 inches, the product 
is 600,000 ; that is, the grain of gold may 
be actually divided into at least half a mil- 
lion of particles, each of which is perfectly 
apparent to the naked eye. Yet, if those 
particles are viewed in a good microscope, 
they will appear like a large surface, the 
ten-thousandth part of which might by 
this means be easily discerned. An inge- 
nious artist in London has been able to 
draw parallel lines upon a glass plate, as 
also upon silver, so near one another, tliat 
10,000 of them occupy the space of one 
inch. Those tines can be seen only by the 
assistance of a very good microscope. An- 
other workman has drawn a silver wire, 
the diameter of which does not exceed the 
750th part of an inch. But those prodigies 
of human ingenuity will appear extremely 
gross and rade, if they are compared with 
the immense subtilty of matter which may 
every vfhere be observed amongst the works 
of nature. The animal, the vegetable, and 
even the mineral kingdom, furnish nume- 
rous examples of this sort. What must be 
the tenuity of the odoriferous parts of musk, 
DIV 
when we find that a piece of it will scent 
a whole room in a short time, and yet it 
will hardly lose any sensible part of its 
weight ! But supposing it to have lost one- 
hundredth part of a grain weight, when 
this small quantity is divided and dispersed 
through the whole room, it must so expand 
itself as not to leave an inch square of 
space where the sense of smell may not 
be affected by some of its particles. How 
small must then be the weight and size of 
one of those particles! The human eye, 
unassisted by glasses, can frequently per- 
ceive insects so small as to be barely dis- 
cernible. The least reflection must show, 
that the limbs, the vessels, and other parts 
of such animals, must infinitely exceed in 
fineness every endeavour of human art. 
But the microscope has discovered won- 
ders that are vastly superior, and such in- 
deed as were utterly unknown to our fore- 
fathers, before the invention of that noble 
instrument. 
Insects have been discovered so small as 
not to exceed the 10,000th part of an inch : 
so that 1^)00,000,000,000, of them might 
be contained within the space of one cubic 
inchj yet each animalcule must consist of 
parts connected with each other ; with ves- 
sels, with fluids, and with organs necessaiy 
for its motions, for its increase, for its pro- 
pagation, &c. How inconceivably small 
must those organs be ! and yet they are 
unquestionably composed of other parts . 
still smaller, and still farther removed from 
the perception of our senses. 
DIVISION, in general, is the separating 
a thing into two or more parts. Although 
the mechanical division of bodies separates 
them into smaller parts, it cannot extend 
to the primary particles of any body, and 
is, consequently, incapable of breaking 
what is called the aggregation, Division is 
also reckoned among the terms in che- 
mistry, but not very properly, as it is 
merely used preparatory to other opera- 
tions, particularly solution: for this it is 
useful, as it increases the quantity of sur- 
face, and the points of contact of any body. 
Division. See Algebra and Arith- 
metic. 
Division, among logicians, is the expli- 
cation of a complex idea, by enumerating 
the simple ideas whereof it is composed; 
in which sense it is nearly allied to defini- 
tion, only that this last regards names and 
things, whereas division is employed wholly 
about ideas. 
When the parts of an idea are divided, 
