288 Votatility of Metals. [May, 



trunk, yet is by no means difficult in many instances. The ex- 

 amples given in the plate will, I think, be sufficient to prove that 

 there is much in the doctrine I have attempted to establish, and 

 the reader can if he pleases compare several other kinds of wood 

 which may be at hand, and thus satisfy himself of its value as a 

 means for discriminating genera and species. 



VOLATILITY OF METALS. 



Few persons are aware that the metals are volatile. Mercury, 

 lead, copper, zinc, etc., are all more or less susceptible of assum- 

 ing a state of vapor. Zinc at a red heat flies off' into the air, and 

 condenses in cooling into white downy matter, like the lightest 

 of cotton. Lead also rises into vapor in the process of smelting, 

 and is diffiised in invisible particles thiough the atmosphere. It 

 becomes a poison in this state, and is injurious to workmen. Mer- 

 cury is surrounded by an atmosphere of its own particles at the 

 common temperature, and wastes slowly. That copper is volatile 

 at a comparative low temperature, may be proved by holding a 

 slip of the metal in the flames of a lamp, when the flame is co- 

 lored green by the escape and volatilization of the metal. Hence 

 in the reduction of the ore, much escapes, and is wasted in the 

 process when conducted in the ordinary way. 



A few metallurgists being aware that much was lost in this 

 way, have devised plans lor condensing the volatilized metal. 

 Thus it is stated in a Merthyr paper, that Messrs. Vigors & Co., 

 in Cwm Avon, have constructed a tunnel for consuming and con- 

 veying copper smoke, 1,100 yards in length, viz., from the smelt- 

 ing furnaces to the top of the high hill towards the north-west, 

 called Molly Mynyddau. In this elevated spot the small quantity, 

 if any, that will escape precipitation, will find its way into the 

 air. Few persons, probably, are aware of the immense quantity 

 of copper thus saved to the proprietors, which in former times 

 was deposited in the neighboring lands, subjecting them to most 

 expensive actions. In a tunnel not long since made by Messrs.Wil- 

 liams & Co., in their works on the Swansea river, 200 tons of 

 copper w^ere taken out, which had been precipitated in the short 

 space of one year — the value of this was =£2,000, and much was 

 still left in the tunnel. Chambers are made in the tunnel for at- 

 tracting the smoke, which is further promoted by the use of steam, 

 so that little of it is allowed to reach the place of exit till it has 

 deposited in transitu all its substance. This material, therefore, 

 which not only was formerly lost, but did serious mischief to the 

 adjoining lands, thereby entailing law-suits of ruinous expense, 

 becomes now a matter of profit. 



