Axtivucive Coul of Rhode-Island. 83. 
Many pieces resemble, Hed strongly, | the compact mag- 
netic iron stone; others in the kind of lustre, approxi ximate 
more to pitch stone and semi nell 
The hardness is moderate: it is scratched by a knife, and 
the powder is black ; by intense ignition, it it becomes hard 
—— to seratch glass 
mean specific gravity is os 75, but there is considera- 
ble paskety in different specim 
ecomes electric by heat, 8 so asto move a delicate needle, 
suspended by a thread, b 'y friction: 
ts structure is slaty and columna 
in the direction of the schistose =e betwee which it 
lies, the structure is slaty, but it is ae in the opposite 
direction, into innumerable columnar masses, so that a con- 
siderable piece has a strong ccoomiionse to a group of basalt 
er trap rocks, presenting a series of verti ical fronts and ir- 
regular columns retreating, by escarpements. In conse- 
quence of this structure, this coal b into 
ments and parallelopipeds. and not into wedge-chaped 
pieces.* 
It appears probable that the seams, a to the slaty 
structure of this coal, have been rendered more numerous and 
more evident, by the injuries which time = efiactads upon 
the upper strata, but it is searcely credible, that they should 
have been produced in that way, and they therefore belong; 
as it would seem, to the original structure of this mineral. 
. racture ts compact. In using the word fracture I 
here refer to the aggregation of the parts, na are ee 
pn = the seams depending on the structu po: 
ed out. These parts present a multitude ‘of small solids 
which have a different structure in opposite 
eihah-tetbe slaty: structure, the fracture ale ndhaahenmeats 
very granular, ‘like the most compact 
iron ores ; ree in the o direction it is smooth, éven, al- 
most specular, and not unfrequently —— to flat con- 
* This peculiarity of structure has an important effect on the combnstibili- 
y of the coat. When it is thrown into the faroncé, ts: not prone to 
choked : the pieces lie so that the air readily finds its way among them, and 
ronepeg . 
EE 
3 
2 
# 
fp 
° 
e 
#2 
ee 
a 
rus readily, the 
'y, that ee aa of air andes freely. Very lle of this coal i ig in the 
peaking: reduced to powder, and for this reason there is not m hb loss in 
ing 
VOL. INO. 1; 12 
