154 Scientific Intelligence. {Auc. 
they were employed in this operation, the gas backed against the 
current of atmospheric air, and exploded at the lights which were 
placed to windward of the foul part of the workings. Mr. George 
Fogget being ill, was obliged to leave his two brothers and their 
companions before the accident happened, and nearly reached the 
bottom of the pit, accompanied hy .Robt. Copeland, who was em- 
ployed in the rail-way, when they felt the shock of an explosion. 
They immediately returned, and had proceeded to within 200 yards 
of the place where Geo. -Fogget: had-left his brothers, when Cope- 
land found it impracticable to go further with safety, on aecount of 
the after-damp. He then advised Geo. Fogget to return with him 
to give the alarm; but this hé réfused to do, and persisted in going 
in-by to look after his brothers, and James Young, his son-in-law. 
He unfortunately fell a victim to his exertions; he died of suffoca- 
tion, and his body was found lying beside those of his two brothers. 
John Ledger, the only survivor, was within 20 yards of the candles 
at which the gas fired, and saw it fire; he was slightly hurt, but, 
from the effect of the after-damp, lay about ten hours in a state of 
insensibility before he could be rescued from his perilous situation. 
The above accident forms another powerful reason of the necessity 
for the establishment of some general and permanent fund for the 
relief of the survivors of those who suffer in the mines. 
xX. Nickel-Antimonerz. 
This new ore of nickel has been lately analyzed by Dr. John. 
He found the constituents as follows :— 
Nickel oo... p00 cpyee ces eas nore ce me 23°38 
Antimony, with arsenic, and a trace 61-68 
OL TOD) so) 0 area: side: «sete viiniei e,euere sic . : 
BOAT ae ae as 0 BSR win wee me Ses 14°16 
Unknown body, probably lead or} 08 
silver, with silica ....+.ees+eee- 
A; 100°00 
XI. New Curve. 
(Lo. Dr. Thomson.) 
SIR, 
By presenting to the readers of the Annals of Philosophy the 
following curve, which I denominate a radiatrix, you EN 
Genesis of the Curve.—If one extremity, O, of the radius of.a 
etircle be made to trace the circumference, the other extremity, V, 
moving always in the direction of a given point, F, in the circum- 
ference will describe a curve called a radiatrix. 
Definitions.—1\. The directing point, F, is the focus. 2. Any 
estraight line, F P or F P’, drawn from the focus to any point in 
-the curve is a chord. 3. The chords F V and FV’, which pass 
sthrough the centre of the circle, are the interior and exterior axes. 
