e
of Jalisco, long before the advent of Cortes and the Spaniards.

Regarding the subject of the mining and metallurgy of the Aztecs and
their predecessors in prehispanic days, it must be recollected that
historical knowledge about it is exceedingly meagre, and the details of
their operations in this field of industry are buried in much
obscurity.

The Spanish advent wrought a marked change in the history of mining in
the country. The Spaniards began to work mines as early as 1526, and
continued their exploitation until 1810, the time of the War of
Independence, at which period the value of the yearly output was
27,000,000 dollars. There was a general expulsion of the Spaniards in
1829. It was, however, in 1700 that the most marked period of Spanish
mining began. The production of gold and silver from 1522 to 1879,
according to the most reliable authorities, is given approximately as
3,725,000,000 dollars, of which gold formed 4 to 8 per cent. Indeed,
the staple product of Mexico has ever been silver, in those remote
times as it is to-day, and it has been calculated that possibly
one-third of the existing quantity of silver in the world has come from
the lodes of the Sierra Madre of Mexico.

The early Spaniards, whilst they did not despise the indication left or
given by the Aztecs in the discovery of rich mines, struck out for
themselves and found the great lodes which yielded fabulous fortunes in
silver to their fortunate owners. These adventurous spirits spread over
the whole of the country bordering upon the Sierra Madres, stimulated
by the rich finds of silver mines successively made in one region or
another. They have left old workings in almost every region where
minerals exist, and they extracted great _bonanzas_ with their crude,
old-fashioned appliances. Ancient corkscrew-like workings, analogous
more to the burrowings of animals than the excavations of man,
honeycomb the crests of lodes and veins in every part of the country.
After yielding fortunes to their workers these mines were abandoned,
not because they were worked out, but for lack of appliances for
drainage and hoisting, and in this condition, flooded or caved-in,
remain innumerable of their old treasure-chambers to this day.

But not all the Spaniards' workings were of this nature. Magnificent
tunnels were run by them into the bowels of hills, tunnels whose
enormous dimensions excite the wonder of the mining engineer of to-day.
In some instances