270 GEOLOGICAL SURVEY 
Fig. 39 isa plan and section, a the plan, and 6 a longitudinal section ; e the fire place, d the bridge, 
f the doors through which the furnace is charged and the lime withdrawn, g the ash pit, / the door 
of fire place, and c the chimney. 
The marl is to fill the whole space a, to the level of the top of the bridge, over which the flame 
is reverberated, producing intense heat, that is sufficient to calcine the sand in 6 hours. 
Tcannot see why any demand for lime may not be supplied, by such a process, from the inex- 
haustible beds of rich marl of the State. 
METALLURGY. 
With the exception of the manufacture of iron, there is scarcely any operation in the State that 
comes under this head; for the extraction of gold from the ores can scarcely be ranked with metal- 
lurgic processes. 
Iron, on account of its connexion with the progress and arts of civilization, as well as for the vast 
value it receives from labor and skill, has, in every country, raised at all above barbarism, excited 
the greatest attention. 
Malleable or native iron is of doubtful existence, on our globe; it is always combined with oxygen 
in certain proportion, and is further mixed with such foreign substances as silica, alumina, &c. To 
remove these impurities, and to obtain the iron in the malleable state, in the greatest quantity and 
of the best quality of which the ore will admit, and at the least possible expense, is the problem, to 
the successful solution of which the skill and attention of the Iron Master must always be directed. 
The preliminary steps, of course, must always be an accurate knowledge of the materials opera- 
ted upon, in all their relations. We have as yet no schools in which the practice and principles of 
Metallurgy are taught; the consequence is, that we have the principles without the practice, or more 
frequently the reverse of this. New establishments, that commence with untried materials, suffer 
most from this cause. What is called a ‘practical man’ is employed, who is perfectly skilled in 
carrying out all the processes that long experience has taught him were best adapted to the mate- 
rials on which he was accustomed is operate. He finds himself placed under new circumstances, 
and with materials entirely different from those to which he was accustomed; his old processes he 
discovers are inapplicable, and his want of knowledge of principles prevents the introduction of the 
proper modifications. Alteration after alteration is made, often at vast expense, the profits of the 
company are swallowed up, or their means exhausted, and doubt or mistrust hangs over the whole 
