and makes the basis of the glazing of all the earthen and pottery
wares.

_Refining_, cleansing, purifying.

_Varnishes_, preparations for beautifying and preserving
various articles.

What is peculiar to the ore of Lead?

The ore of this metal is so poisonous, that the steam arising from the
furnaces in which it is smelted infects the grass of all the
neighboring places, and kills the animals which feed on it: culinary
vessels lined with a mixture of tin and lead, are apt to convey
pernicious qualities to the food prepared in them. There are various
preparations of lead, serving for different purposes.

_Infects_, corrupts.

_Culinary_, adapted to the purposes of cooking.

_Pernicious_, hurtful, dangerous.

_Ore_, the mineral soil, earth, or stone dug out of the
mines, which contains the metal.

What is Black Lead?

It is a kind of mineral, of a deep shining black or bluish color, soft
and unctuous to the touch; it is insoluble in acids, and infusible by
fire. Black lead has been found in many parts of the world, in a state
of greater or less purity, but it is the English black lead which is
the most esteemed.

_Insoluble_, incapable of dissolving.

_Infusible_, not capable of being melted.

Is Black Lead a proper term for this mineral?

No; because, in reality, there is not a particle of lead in it. On the
spot where it is procured, it is called by two or three different
names, but the most usual is Plumbago.

Where is the best Black Lead found?

The best and greatest quantity is found in England, in a mine near
Keswick, in Cumberland. It is much used for pencils or crayons, for
writing, drawing, &c.; for this purpose it is sawn into slips, and
fitted into a groove in a strip of soft wood, as cedar, &c., over
which another is placed and fastened with glue.

What is Platina?

A metallic substance, more recently discovered than the metals already
described; and analogous to the perfect metals, especially gold,--many
of whose properties it possesses.

_Analogous_, bearing a resemblance.

Whence is its name derived?

It is the diminutive of _plata_, silver, to which it appears very
similar; platina being a silver-colored metal, in small grains.

_Diminutive_, a word lessening the meaning of the original.

Whence is it obtained?

Mostly from Russia, and, also from South America. Its color does not
tarnish by exposure