1864. | Mining, Mineralogy, and Metallurgy. 147 
mines, the engincering difficulties of which are rapidly augmenting 
with the increasing depth. 
The uncertainty which attends the conditions of any of our 
mineral lodes or veins, is one of the causes which has led to the 
unfortunate spirit of gambling which marks too many Mining specu- 
lations. It may never be possible to pronounce with certainty, 
whether a mineral lode shall prove rich, in the metalliferous ores, in” 
depth. But it is certainly within the limits of human knowledge to 
be able to pronounce on the high probabilities of any subterranean 
exploration being remunerative or otherwise. 
The Philosopher who stands upon the surface of the Earth, and 
frames his hypothesis, as to the laws by which the metals have been 
deposited in the fissures of the rocks, is as likely to run wildly wrong, 
as the untaught miner, who, without a knowledge of one of the Physical 
Forces, persuades himself that he has an unfailing rule for determining 
the value of the hidden treasures. Neither the one nor the other will 
ever advance knowledge by his guesses. Teach the Miner to observe 
carefully, and to record his observations correctly—then call in the 
aid of the Philosopher, and his deductions from a sufficient number of 
well-observed facts will possess a high value. It is an important and 
a most favourable feature of the present time, that several practical 
miners are employed in endeavours to determine if any constant law 
can be discovered in relation to the accumulation of the Metalliferous 
ores in lodes. 
M. Moisenet, Ingénieur des Mines,—who has himself examined 
with great industry the Metal Mines of this country,—has endeavoured 
to refer the conditions of our mineral deposits to actions influenced 
by the direction of our great mountain ranges. In this country 
Mr. Lonsdale Bradley has published a valuable set of sections of 
the strata, in the lead-bearing rocks of Swaledale; and given careful 
explanations of the actual conditions observed in the veins. 
Those sections instruct us on some points, which from their almost 
constant occurrence, assume the conditions of a law. These are that 
Limestoves and Cuerts are the beds which are productive of lead, and 
that the Grits and Pats are wholly unproductive. All mineral veins 
must be regarded as lines of dislocation; the strata seldom being pre- 
cisely similar on both sides of the fissure or lode. Those disturbances 
are locally termed “ throws.” The sections published by Mr. L. Brad- 
ley appear to prove, amongst other facts, “ That veins of simple throws 
are the most productive of lead-ore from having ore-bearing or ore- 
producing beds on each side of the veins, opposite or nearly so to each 
other ;” “that veins of large throws are invariably unproductive, because 
the ore-bearing beds are thrown past each other, and that cross veins 
of large throws when productive of lead ore are usually so in the 
Limestones.””* 
fully drawn to scale—in Mr. Bradley’s book, these conditions are 
clearly shown. The accompanying lithographed examples of two 
lands of “throw” will fully illustrate this position. 
* «An Inquiry into the Deposition of Lead Ore in the Mineral Veins of Swale- 
dale, Yorkshire.” By Lonsdale Bradley, F.G.S8. Edward Stanford, London, 1862. 
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