50 Dr John Davy on Oxide of Arsenic. 
most delicate, the most sensitive of noxious influences of all 
the Salmonide. It is an established fact, that in the two 
or three instances in the Lake District, that mines have 
been opened in the vicinity of lakes, their drainage entering 
the lakes, the charr has either entirely disappeared, as at 
Ulswater, or has become very scarce, as at Coniston-water, 
the trout, a hardier fish, remaining. J have examined the 
water flowing from the Coniston copper mines into the lake 
of the same name, and have detected in it distinct traces of 
arsenic ; and I have obtained a like result from the examin- 
ation of the water flowing into Ulswater, which receives the 
drainage of an adjoining lead mine. 
Recently, much alarm has been felt from apprehension 
of arsenic-poisoning, owing to the great use made of some 
of its compounds, especially of Scheele’s green—the cuprio- 
arseniate—in colouring paper and articles of dress. Pro- 
bably the apprehension is an exaggerated one; but yet there 
~geems some foundation for it, especially in the case of 
women employed in making artificial flowers, and in that 
of ladies wearing those flowers in ball-dresses, coloured by 
the arsenic compound. If there were only a risk of injury, 
and that there certainly is in these instances, of a poisonous 
effect, ought it not to act powerfully as a prohibition to the 
further use of articles so coloured? Even the most insen- 
sate votaries of fashion who may defend crinoline, asserting 
that, with caution, they are safe from combustion, will hardly 
venture to defend the use of a poisoned dress, from the slow 
effects of which, undermining health and spoiling beauty, 
no ordinary precautions can be effectual. 
When we reflect on the abundance of arsenical pyrites 
in most of our mining districts, and the numerous springs 
issuing from mineral strata, the water of which is used by 
the inhabitants, it may be asked how is it that arsenicated 
water is not of common occurrence, and its poisonous 
qualities well established? The answer to this, I appre- 
hend, is not difficult, resting on two facts—one, the slight 
solubility of the oxide of the metal in cold water; the other, 
its harmlessness in very minute quantities. As to the first, 
so slowly is it soluble at ordinary temperatures, that we learn, 
on good authority, it may be digested for many days with 
