314 Companications respecting Sir H. Davy’s Safe-Lump. 
fire-damp from a stratum of stone. In approaching the con- 
fines of the foul air, the flame of the wick increased in bulk, 
and by progressively advancing, the wire cylinder first became 
filled with flame from the explosive mixture, and at last the 
whole extinguished without producing the least flame on the 
exterior of the wire. These experiments were frequently re- 
peated with the same effect. We then proceeded to the Triak 
Inbanks, where we have for many months been working with 
steel-mills, not daring to introduce a candle on account of the 
quantity of fire-damp generated. In these places the same 
safety and effects were found as in Russia drift, to the great as~ 
tonishment of the workmen employed. 
«© The simplicity of the lamp is beyond description, and, ex- 
cept from the repeated proof of its security, to look at, it ap- 
pears incredible. 
‘* In all places where danger is the least suspected, there can 
be no doubt the lamp will be absolute security if properly ap- 
plied, and in a little time it will become in general use. The 
light produced from the lamp (trimmed with spermaceti oil) was 
quite sufficient for the ordinary purposes of working, The thanks 
of miners must ever be given to Sir Humphry Davy for this 
momentous discovery. I have the honour tobe, &c. 
“* Joun PEILE.” 
We have great pleasure in stating that the coal-trade has libe- 
rally presented 100 guineas to Mr. Stevenson, of Killingworth 
Colliery, for his ingenious lamp described in a preceding number 
of the Philosophical Magazine, which, though superseded by Sir 
Humphry Davy’s more perfect invention, not only evinced great 
ingenuity, but promised much comparative safety to the miners, 
The public have been amused within the last few weeks, by a 
boy with extraordinary calculating powers, who is exhibited by 
his friends in the Great Room at Spring Gardens: Perhaps the 
following short account of the calculating phenomenon of Eng- 
land, as he is called, will be a satisfaction to our readers. 
' George Bidder was born in a cottage at Morton Hampstead, 
twelve miles from Exeter, Devonshire, on the 14th of June 1806. 
His father William Bidder, a hard-working mason, principally 
occupied in making the stone fences with which that country 
abounds, has seven children, four boys and three girls: the boys 
assist the father, girls at service ; George, the youngest but two, 
whose time was employed as country children’s are, went toa 
three-halfpence a-week school till seven years old, when the first 
proof he gave of his extraordinary abilities was in reckoning the 
nails in a horse’s four shoes, and by degrees doubling them from 
a farthing 32 times; this brought on other questions, when je 
ready 
