analysis is easier than synthesis and that creative chemistry is the
highest branch of his art.

This explains why chemists discovered how to take rubber apart over
sixty years before they could find out how to put it together. The first
is easy. Just put some raw rubber into a retort and heat it. If you can
stand the odor you will observe the caoutchouc decomposing and a
benzine-like liquid distilling over. This is called "isoprene." Any
Freshman chemist could write the reaction for this operation. It is
simply

C_{10}H_{16} --> 2C_{5}H_{8}
caoutchouc isoprene

That is, one molecule of the gum splits up into two molecules of the
liquid. It is just as easy to write the reaction in the reverse
directions, as 2 isoprene--> 1 caoutchouc, but nobody could make it go
in that direction. Yet it could be done. It had been done. But the man
who did it did not know how he did it and could not do it again.
Professor Tilden in May, 1892, read a paper before the Birmingham
Philosophical Society in which he said:

I was surprised a few weeks ago at finding the contents of the
bottles containing isoprene from turpentine entirely changed in
appearance. In place of a limpid, colorless liquid the bottles
contained a dense syrup in which were floating several large
masses of a yellowish color. Upon examination this turned out
to be India rubber.

But neither Professor Tilden nor any one else could repeat this