ss
weeds and old stones, may do real service to their country and their
countrymen, as I hope you will some day.

There was a clergyman named Henslow, now with God, honoured by all
scientific men, a kind friend and teacher of mine, loved by every little
child in his parish. His calling was botany: but he knew something of
geology. And some of these Coprolites were brought him as curiosities,
because they had fossils in them. But he (so the tale goes) had the wit
to see that they were not, like other fossils, carbonate of lime, but
phosphate of lime--bone earth. Whereon he told the neighbouring farmers
that they had a mine of wealth opened to them, if they would but use them
for manure. And after a while he was listened to. Then others began to
find them in the Eastern counties; and then another man, as learned and
wise as he was good and noble--John Paine of Farnham, also now with
God--found them on his own estate, and made much use and much money of
them: and now tens of thousands of pounds' worth of valuable manure are
made out of them every year, in Cambridgeshire and Bedfordshire, by
digging them out of land which was till lately only used for common
farmers' crops.

But how do they turn Coprolites into manure? I used to see them in the
railway trucks at Cambridge, and they were all like what I have at
home--hard pebbles.

They grind them first in a mill. Then they mix them with sulphuric acid
and water, and that melts them down, and parts them into two things. One
is sulphate of lime (gypsum, as it is commonly called), and which will
not dissolve in water, and is of little use. But the other is what is
called superphosphate of lime, which will dissolve in water; so that the
roots of the plants can suck it up: and that is one of the richest of
manures.

Oh, I know: you put superphosphate on the grass last year.

Yes. But not that kind; a better one still. The superphosphate from the
Copiolites is good; but the superphosphate from fresh bones is better
still, and therefore dearer, because it has in it the fibrine of the
bones, which is full of nitrogen, like gristle or meat; and all that has
been washed out of the bone-earth bed ages and ages ago. But you must
learn some chemistry to understand that.

I should like to be a scientific man, if one can find out such really
useful things by science.

Child, there is no saying what you might find out, or of what use you may
be to your fellow-men. A