70 The Naturalist in Nicaragua 
The gold-mines of Santo Domingo are in veins or lodes of 
auriferous quartz that run parallel to each other, and are so 
numerous that across a band more than a mile in width one 
may be found every fifty yards. All that have been worked 
vary greatly in thickness; sometimes within a hundred yards 
a lode will thicken out from one to seventeen feet. Their 
auriferous contents vary still more than their width. The 
richest ore, worth from one to four ounces per ton, occurs in 
irregular patches and bands very small in comparison with 
the bulk of the ore stuff, which varies in value from two to 
seven pennyweights per ton. The average value of all the 
ore treated by the Chontales Mining Company, up to the end 
of 1871, has been about seven pennyweights per ton, and 
during that time small patches have been met with worth 
one hundred ounces of gold per ton. The gold does not 
occur pure, but is a natural alloy of gold and silver, contain- 
ing about three parts of the former to one of the latter. 
Besides this metallic alloy (to which, for brevity, I shall, in 
the remarks I have to make, give its common designation of 
gold), the quartz lodes contain sulphide of silver, peroxide of 
manganese, peroxide of iron, sulphides of iron and copper, 
and occasionally ores of lead. 
The quartz is generally very friable, full of drusy cavities, 
and broken up into innumerable small pieces that are often 
coloured black by the peroxide of manganese. The gold is 
in minute grains, and generally distributed loosely amongst 
the quartz. Pieces as large as a pin’s head are rare, and 
specimens of quartz showing the gold in it are seldom met 
with, even in the richest portions of a lode. The fine gold- 
dust can, however, easily be detected by washing portions of 
the lode-stuff in a horn. The quartz and clay is washed 
away, and the gold-dust sinks to the bottom, and is retained 
in the horn. This is the usual way in which a lode.is tested 
by the mining agents, and long practice has made them very 
expert in valuing the ore by the wash in the “ spoon.” 
Although most of the gold occurs loose, amongst the soft 
portions of the lode, the hard quartz also contains it dissemi- 
nated in minute grains throughout. These can be obtained 
in the horn by pounding the quartz to powder and then 
washing it. 
One feature in the distribution of gold in the quartz lodes 
