852 Messrs Burstall and Hill’s Steam Carnage. 
It only remains for us to say, that the object of the paten- 
tees is, in the peculiar construction of a boiler, to make it a 
store of caloric, they proposing to heat it from 250 to 600 or 
800 degrees of Fahrenheit ; and by keeping the water in a se- 
parate vessel, and only applying it to the boiler when steam is 
wanted, they accomplish that great desideratum in the applica- 
tion of steam to common roads, of making just such a quantity 
of steam as is wanted ; so that when going down hill, where 
the gravitating force will be enough to impel the carriage, all 
the steam and heat may be saved, to be accumulating and given 
out again at the first hill or bad piece of road, when, more be- 
ing wanted, more will be expended. 
The engines are what are called High-pressure, and capable 
of working to 10-horse power, and the steam is purposed to be 
let off into an intermediate vessel, that the sound emitted may 
be regulated by one or more cocks. 
Art. XXX.— On the Formation of Ores by the Action of the 
Atmosphere and of Volcanic Heat. 
In the last Number of this Journal, page 190., we men- 
tioned the formation of brown hematite by the action of wa- 
ter on cast-iron pipes. We have now to enumerate some 
other facts of the same description. Noggerath, in the third 
volume of his work, entitled, 46 Das Gebirge in Rheinland, 
Westphalen,” notices the formation of crystals of red copper-ore 
on a fragment of a Roman copper vessel, which was dug up near 
to the city of Bonn. The inner and outer surface of the vessel 
was covered, next to the copper, with a delicate layer of red 
copper in small but beautiful dodecahedral and cubo-octahedral 
crystals, and immediately over this was an extremely thin layer 
or film of a green colour, and which might be considered as ma- 
lachite. Noggerath also observed, in a collection of antiqui- 
ties at Triers, some wrought pieces of copper, several inches 
long and pretty thick, which were found amongst Roman 
ruins, and appeared to have served as architectural ornaments. 
They were so corroded on the surface, that little of their ori- 
ginal form could be observed. In some places traces of gilding 
