Chap. X. AND ITS SILVEE MINES. 357 
which are visible at the foot of the rocks enclosing the 
valley. Water fails greatly during the dry season, and 
the smelting operations, for which it is indispensable, 
cannot be carried on. It was principally on this account 
that thesmelting-works were transferred from hence to Chi- 
huahua, where there is a sufficient amount of water-power. 
Good drinking-water is also much needed at Santa Eulalia, 
that of the place being rendered poisonous by metallic 
particles. I can offer no opinion as to the correctness of 
this assertion. Two facts are however certain, — first, that 
gentlemen from Chihuahua, who are obliged to remain 
there, drink no water but what is fetched from Chihuahua ; 
and second, that I fell ill the day after my arrival, with 
gastric fever, which my companion attributed to my having 
incautiously drank some of the water of the locality. The 
greater number of the inhabitants, however, are too poor 
to have water fetched twelve miles daily. They have 
probably other springs nearer in the mountain. 
This illness must be my excuse if my remarks upon this 
interesting place are few and insufficient. I was taken 
ill the day after my arrival, but during the forenoon visited 
the Guadalupe mine, which had been shortly before opened 
high up the mountain. The silver-ore, consisting princi- 
pally of chloride and bromide of silver, 1 appears in a layer 
which enters the mountain almost horizontally among 
caverns and stalactitic formations, between the limestone 
strata of the mountain. The composition of these ores was 
as little understood here as at Chihuahua ; my previous 
definition of their chemical nature has, however, since been 
confirmed by an analysis undertaken by Dr. Genth in 
Philadelphia. To what period the limestone strata belong 
Partly the pure chloride, partly Ernbolit. 
