276 
MINES, METALS, AND GEMS. 
■L/M iviii,*,., , ,UjS 
water colder. Hence arises the superiority of ’ 
for making mechanic instruments or tools, hy 
other metals, and even itself, are filed, drillcO,^ 
to 
The various degrees of hardness given ^ 
on the quantity of ignition it possesses at the 
being tempered, which is manifested by the soc ^ 
colours exhibited on the surface of the imtal, in 
of its receiving the increasing heat, 
lowish white, yellow, gold-colour. 
IOW1311 VVlilLt:( j 
deep blue; — after the exhibition of which tu 
ignition takes place. These colours proceed fron 
These arc. , 
puqde, 
i^AXl LiUli LCliW..t) ^AlCAA.,Vy. A »1V"0^ I . 
scorification on the surface of the heated metal. , oj) 
- - . . . T-i » 1 . .V« 
The lararest iron works' in England are cam 
^ - .- 5 — wbi^V 
CoLEBiioox Dale, in Shropshire. This ca'‘'j|)j 
situated between two towering and variegated In \>e 
with wood, possesses peculiar advantages, the v 
obtained from the adjacent hills, the coals . 
and abundance of limestone frdm the quairies in j 
-r,, .. 1 ..vhibitSi 
The romantic scenery which 
....... - nature here exhib'l^®^ 
works which are carrying on, seem to realize fi' 
' fable of the Cyclops. “ The noise 
&c.” Mr. Young observes, with 
all 
chinory, the flames bursting from the f'arnaceSjj^jjps, 
burning of coal, and the smoke of the jm' 
* altogether horridly sublime.” To coraple c , i j, 
-y — 
liarities of this spot, a bridge, entirely constru p;i^ 
IS here thrown over the Severn. In one placet 
and a chasm is formed ; but such is its firm b*'’ ’ ,j) 
fissure has neither injured its strength nor titihv'^j.|,,t ^ 
The great superiority of Swedish iron 
other countries, for the manufacture of steel, is 
and is a.scribed to the great purity of the ore j^ers / 
the iron is smelted. Hitherto the British steel ml 
oroc^’- , t> 
not been able to employ British iron in theii I ' (-ioi' ’ 
having been found too brittle to bear cevne'’^^^^^.] , 1 ^ 
Its are now makinff bv some very spirited ^ . gd, 
naviu^ uccu luuiui cuu uuutc uaj ut..uA f 
attempts are now making by some very spirited .• r ,|^ 
at Sheffield ; and from the products already od 0'^^ 
Slopes are entertained of ultimate success. ^ j,jni ^,'j 
snost remarkable of the Swedish mines, if ^ ’^^uiC'*'' f 
with propriety be applied to it, is Tabern, a n)0 ^ |i 
considerable size, composed entirely of pt'm ' 
occurring in a large tract of sand ovei whic 
