133 
TAB. CCLXVIL. 
CARBO /- ferriferum. 
Plumbago. Black Lead. 
Class 1. Combustibles. | Order 1. Homogeneous. 
Gen. 6. Carbon. 
Syn. Graphites plumbago. Linn. ed. 13. 3.284. 
Plombagine. De Lisle, 2. 500. , 
———_—_—-- Carbure de fer. De Born, 2. 395. 
Phlogistique saturé de l’acide aérien. Plombagine, 
‘Sciagr. 2. 8. 
Graphit. Emmerl. 2.97. : 
Fer minéralisé par le Carbon. Daubenton, 49. 
Carbon combined with one tenth or one eighth 
of its weight of Metallic Iron. Kirw. 2. 58. 
Tuts curious substance, so extensively used by artists of 
all descriptions, is nowhere found in greater perfection 
than at Borrodale near Keswick in Cumberland. It is also 
found at Crumnock in Ayrshire, and at Kilkenny Well in 
Ireland, besides some other parts of Europe. That from 
Borrodale is made into the finest Black Lead pencils of 
any in the world, and there is a regular sale of it once a 
month in London for that purpose. Jameson says that the 
finer kinds are first boiled in oil, and then cut into tables or 
pencils. He is surely mistaken ; and I think a proper ex- 
amination of the substance in the best pencils is enough to 
prove it*. 
The Plumbago is sold under the title of Black Lead : and 
the larger lumps, above six inches in length, are bought at 
40s. per pound—the middling, from about four inches 
long, for 35s. per pound: and smaller, about the size 
of walnuts, are called pints, and sell at 25s. per pound. 
The buyers or their agents attend and try its goodness 
by scraping it, always rejecting it when sandy, spongy 
or powdery; and it is curious to observe the singular 
shining appearance the examiners make. Sir Joseph 
Banks generally has a few pencils of the best kind 
made for himself and a friend, and no art is used to alter 
the genuine nature of the best Lead. It is, however, said, 
that there is an art known to one or two pencil-makers, by 
* We have boiled various fragments in oil, and find them in no way 
changed :—a red heat softens Plumbago considerably, at the same time 1t 
Loses 6 or 7 per cent. of its weight, 
