[3] See for some interesting information on the system of Cornish
Mining, an article in No. 42 of the present series.
[4] On this point, we refer all who are desirous of pursuing the
subject, to a valuable memoir in the _Annals of Philosophy_, by John
Henry Vivian, Esq., F.R.S., the proprietor of the Hafod Works. This
paper, we may add, is the standard authority on the subject; and is,
with some modification, copied by Drs Ure and Lardner, and by most
popular works upon metallurgy.
[5] The production of this curious substance is explained in an
article on the 'Value of Rubbish,' No. 385.
[6] Notwithstanding this, we were assured by a gentleman connected
with the copper-works, that there is no specific disease arising from
copper-smelting, as in the case of lead. Asthma, rheumatism, and
colds, are the prevailing affections among the men; and even these are
in a great measure due to their own carelessness.