494 
SILVER. 
Sir Hugh Middleton is said to have cleared from 
them 2000 pounds in a month. The same mines 
yielded, about the year 1745, eighty ounces of silver 
out of every ton of lead. The lead ores from 
Brunghill and Skekorn produced also a considera- 
ble quantity of silver. The lead only, in one of the 
smelting-houses at Holywell in Flintshire, produced 
no less than 31,521 ounces, or 3 1264 pounds of sil- 
ver, from the year 1754 to 1 7 7^* “ There are some 
lead-ores in this country,” says Dr. Watson, “ which, 
though very poor in lead, contain between three 
and four hundred ounces of silver in a ton of that 
metal. It is commonly observed, that the poorest 
lead-ores yield the most silver, so that a large quan- 
tity of silver is probably thrown away in England, 
from not having the poorest sort of lead-ores pro- 
perly assayed.” 
Besides the native silver, which is found in a 
metallic state, there are several combinations of this 
metal with different substances, such as sulphur, 
arsenic, &c. When mineralized by the former sub- 
stance alone, it forms the glass, or vitreous silver 
ore, which is subject to great variety of colour. 
Again, when united to both sulphur and arsenic, 
the mass becomes the red, or ruby-like silver ore ; 
the colour of w hich varies from deep red to dark 
gray, in proportion as either of these substances 
prevails. 
According to Brogniart, silver in its mineral 
state is chiefly found in primitive earths, especially 
in those which are deposited in beds, though it is 
