1825.] 
The heat of the electric fiuid is suffi- 
cient to make a metallic wire red hot, 
or to fuse and disperse it; thin slips of 
copper, therefore, nailed to the masts 
of vessels, afford no security; but this 
heat scarcely alters the temperature of 
a bar hardly more than half an inch 
square, on account of its mass; thus, 
the thickness of a lightning-rod need 
not be great; but as the stem should 
overtop the building by eighteen or 
thirty feet, the dase will acquire addi- 
tional support :, yet an iron bar, about 
three-quarters of an inch square, will 
be sufficiently thick for the conductor 
of a lightning-rod, which may be de- 
fined, as preferred, by the electric mat- 
ter, to the surrounding objects, and is 
commonly elevated on buildings intend- 
ed to be protected, descending, with- 
out break or division, to the ground, 
which must be moist, or at once into 
water, into which the conductor should 
be sunk, at least two feet below the 
lowest water mark, if practicable; if 
there be no well convenient, a hole, at 
least six inches in diameter, must be 
dug, ten or fifteen feet deep, into the 
centre of which the conductor must be 
brought, down to the bottom, and the 
hole, then, carefully filled up with char- 
coal, rammed down as tight as possible. 
Should the adjacent soil be dry and 
rocky, a long trench must be dug, hav- 
ing transverse trenches crossing its end, 
to be filled up in the same manner. 
Still, if gutters and drains can be so 
directed as to keep up a continual dis- 
charge of moisture, it is desirable: it is 
plain, however, that iron thus placed 
in immediate contact with moist earth, 
will soon be consumed by rust; but 
the following process will prevent this 
in a great degree:—Having made a 
trench about two feet deep, a row of 
bricks is to be laid in on the broad side, 
and covered by another row, placed on 
the edge; a stratum of charcoal, two 
inches thick, is then to be spread, on 
which the conductor is to be laid; and 
the trench is then to be filled up with 
charcoal, with a row of bricks on the 
top. The conductor, thus guarded, 
will remain unhurt for thirty years. 
A lightning-rod consists of two parts ; 
the stem, which has already been de- 
seribed as projecting above the roof 
into the air; and the conductor, passing 
uninterruptedly from the stem to the 
ground, It (the conductor) should be 
united to the stem, by being firmly 
jammed between the ears of a collar, 
by means of abolt. It should be sup- 
Informasion obtained from a Mandingo Negro. 
197 
ported, parallel to the roof, six inches 
above it, by fixed stanchions; and, be- 
ing bent over the cornice, without 
touching, should be fastened down the 
wall by cramps: at the bottom of which 
it should be bent at right angles, and 
carried, in that direction, for fifteen or 
eighteen feet. 
Iron bars, being brittle and difficult 
to. bend, according to the projection of 
a building, metallic ropes have been pro- 
posed in substitution: fifteen iron 
wires, twisted together, forming one 
strand, and four of these a rope, about 
one inch in diameter. To prevent 
Tusting, each strand is well tarred sepa- 
rately, and after they are twisted to- 
gether, the whole rope is carefully tar- 
red over again. Brass or copper wire 
will, however, be found a still better 
material.— Yours, &c. 
29th August. THERMEs. 
J ——a 
To the Editor of the Monthly Magazine. 
Sir: 
NAVAL officer recently arrived 
from Jamaica, has obtained the 
following information respecting the in- 
terior of Northern Africa, from an intel- 
ligent negro, and has obligingly permitted 
me to hand it over to you. 
InFoRMATION obtained from a ManvIn- 
co Nrcro, at Friendship Grove, on the 
north side of Jamaica, the property of 
Joun Mowatt Bucknor, Esg. - 
“ Hz knows a river called Coara, 
which runs from Cotena into the sea; 
knows not the Joliba, but thinks it is 
in the Coromantee country; knows 
nothing of Timbuctoo, but knows of a 
kind of morass called Cudee ; knows a 
river called Wateree, that runs near the 
Coromantee country to the sea. 
** They take six months to come from 
their country to the sea-side, crossing 
two rivers in the route: the first, called 
Gilboa, one day’s walk distant from the 
second, which is named Neefé: they 
also pass ‘ one big hill’ (a lofty moun- 
tain), called Hoppa. 
“ The names of the towns through 
which they pass in their way to the sea- 
side: first, Gago, half a day’s walk to 
Chocheno ; from thence one day’s journey 
to Apon; thence half a day to Neefé ; 
thence two days to Madadow ; thence 
one day to Labage ; thence half a day 
to Aquail; thence half a day to Raoa, 
and trom thence into the Nago country. 
Never saw a white man before they 
came to the sea-side: they have a king, 
whom they call Surkee. | 
The 
