ANY persons hold the opinion that the metal industries are fortuitous and that the occupation is one
of sordid toil, and altogether a kind of business
requiring not so much skill as labour. But as for
myself, when I reflect carefully upon its special
points one by one, it appears to be far otherwise.
For a miner must have the greatest skill in his
work, that he may know first of all what mountain
or bill, what valley or plain, can be prospected most
profitably, or what he should leave alone ; moreover, he must understand the
veins, stringers1 and seams in the rocks2. Then he must be thoroughly
familiar with the many and varied species of earths, juices3, gems,
stones, marbles, rocks, metals, and compounds4. He must also have a
Fibrae—" fibres." See Note 6, p. 70.
*Cùmmissurae saxorum—" rock joints," " seams," or " cracks." Agricola and all of
the old authors laid a wholly unwarranted geologic value on these phenomena. See description and footnotes, Book III., pages 43 and 72.
*Succi—" juice," or sweet concreti—" solidified juice." Ger. Trans., safftt. The
old English "translators and mineralogists often use the word juices in the same sense,
and we have adopted it. The words " solutions " and " salts " convey a chemical significance
not warranted by the state of knowledge in Agricola's time. Instances of the former use of
this word maybe seen in Barba's " First Book of the Art of Metals," (Trans. Earl Sandwich,
London, 1674, p. 2, etc.,) and in Pryce's Mineralogia Cornubiensis (London, 1778, p. 25, 32).
•In order that the reader should be able to grasp the author's point of view as to his
divisions of the Mineral Kingdom, we introduce here his own statement from De Natura
Fossilium, (p. 180). It is also desirable to read the footnote on his theory of ore-deposits on
pages 43 to 53, and the review of De Natura Fossilium given in the Appendix.
" The subterranean inanimate bodies are divided into two classes, one of which, because
" it is a fluid or an exhalation, is called by those names, and the other class is called the
" minerals. Mineral bodies are solidified from particles of the same substance, such as pure
" gold, each particle of which is gold, or they are of different substances such as lumps which
" consist of earth, stone, and metal ; these latter may be separated into earth, stone and
" metal, and therefore the first is not a mixture while the last is called a mixture. The first
" are again divided into simple and compound minerals. The simple minerals are of four
" classes, namely earths, solidified juices, stones and metals, while the mineral compounds
" are of many sorts, as I shall explain later."
" Earth is a simple mineral body which may be kneaded in the hands when moistened,
" or from which lute is made when it has been wetted. Earth, properly so called, is found
" enclosed in veins or veinlets, or frequently on the surface in fields and meadows. This
" definition is a general one. The harder earth, although moistened by water, does not at
" once become lute, but does turn into lute if it remains in water for some time. There are
" many species of earths, some of which have names but others are unnamed."
" Solidified juices are dry and somewhat hard (subdurus) mineral bodies which when
" moistened with water do not soften but liquefy instead ; or if they do soften, they differ
" greatly from the earths by their unctuousness (pingue) or by the material of which they
" consist. Although occasionally they have the hardness of stone, yet because they preserve
" the form and nature which they had when less hard, they can easily be distinguished from
" the stones. The juices are divided into 'meagre' and unctuous (macer et pinguis). The
" 'meagre' juices, since they originate from three different substances, are of three species.
"They are formed from a liquid mixed with earth, or with metal, or with a
" mineral compound. To the first species belong salt and Nitrum (soda) ; to the second,
" chrysocolla, verdigris, iron-rust, and azure ; to the third, vitriol, alum, and an acrid juice
" which is unnamed. The first two of these latter are obtained from pyrites, which is
" numbered amongst the compound minerals. The third of these comes from Cadmia (in
" this case the cobalt-zinc-arsenic minerals ; the acrid juice is probably zinc sulphate). To
" the unctuous juices belong these species : sulphur, bitumen, realgar and orpiment. Vitriol
" and alum, although they are somewhat unctuous yet do not burn, and they differ in
" their origin from the unctuous juices, for the latter are forced out from the earth by heat,
" whereas the former are produced when pyrites is softened by moisture."