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Geology as a Science and an A rt. 
[August, 
conclusion that pure science does not pay ; that is not at all 
an unlikely conclusion for him to come to, and he may 
therefore make it his profession to apply his knowledge to 
practical ends. He may become an assayer, and connecting 
himself, say, with the Cape Copper Company, may determine 
for them the amount of copper and other materials in their 
ores. Now I call assaying an Art, not a Science, and I think 
the assayer should be considered a professional man, not a 
man of science ; for the man of science applies his know- 
ledge to the widening the boundaries of our knowledge, or 
making our existing knowledge more completely organised 
or more rigidly exadt, not immediately to the practical ends 
of every-day life. In the same way the navigator, the land- 
surveyor, the engineer, the medical practitioner are men who 
have to learn some of the fadts and principles established by 
Science, for the sake of their professional work ; but unless 
they are extending the boundaries of our knowledge, or con- 
tributing to the organisation of that knowledge, they are not 
men of science, in what I believe to be the true sense of the 
term. Nevertheless they will be successful in so far as they 
employ the method of science : that method is to proceed by 
observation and experiment , by guarded hypothesis and careful 
verification from the known to the unknown , on the well-founded 
assumption of the uniformity of Nature. Let me give you an 
example of the application of this method. The lead ob- 
tained from certain English and other ores contains a varying 
quantity of silver, often several ounces to the ton. Up to 
the year 1833, however, no method was known by which 
lead, containing less than 8 ounces of silver to the ton, could 
be desilverised. Thus not only was a large quantity of valu- 
able metal lost, but the lead itself was rendered by the silver 
harder, and therefore for certain purposes less valuable. In 
1833, Mr. H. L. Pattinson, among others, was endeavouring 
to solve this problem of the separation of these two metals, 
and it chanced that he dropped a crucible containing molten 
lead rich in silver. Such an accident might happen a hun- 
dred times and nothing come of it. But Mr. Pattinson’s 
keen eye detected crystalline grains in the spilt metal, and 
he carefully picked some of them out for special examina- 
tion. I do not know what thoughts were in his mind when 
he did so, but he may not improbably have said to himself 
something of this sort : — “ When sea-water freezes the ice 
formed is comparatively free from salt, while the water re- 
maining is comparatively rich in salt ; it may be that these 
solid grains are comparatively free from silver, while the lead 
remaining is comparatively rich in silver.” If he argued thus 
