around the benzene ring changes the character. The two derivatives of
phenol, which we are now considering, have two substituting groups. One
is--O-H (called the hydroxyl group). The other is--CHO (called the
aldehyde group). If these are opposite (called the para position) we
have an odorless white solid. If they are side by side (called the ortho
position) we have an oil with the odor of meadowsweet. Treating the
odorless solid with methyl alcohol we get audepine (or anisic aldehyde)
which is the perfume of hawthorn blossoms. But treating the other of the
twin products, the fragrant oil, with dry acetic acid ("Perkin's
reaction") we get cumarin, which is the perfume part of the tonka or
tonquin beans that our forefathers used to carry in their snuff boxes.
One ounce of cumarin is equal to four pounds of tonka beans. It smells
sufficiently like vanilla to be used as a substitute for it in cheap
extracts. In perfumery it is known as "new mown hay."

You may remember what I said on a former page about the career of
William Henry Perkin, the boy who loved chemistry better than eating,
and how he discovered the coal-tar dyes. Well, it is also to his
ingenious mind that we owe the starting of the coal-tar perfume business
which has had almost as important a development. Perkin made cumarin in
1868, but this, like the dye industry, escaped from English hands and
flew over the North Sea. Before the war Germany was exporting
$1,500,000 worth of synthetic perfumes a year. Part of these went to
France, where they were mixed and put up in fancy bottles with French
names and sold to Americans at fancy prices.

The real vanilla flavor, vanillin, was made by Tiemann in 1874. At first
it sold for nearly $800 a pound, but now it may be had for $10. How
extensively it is now used in chocolate, ice cream, soda water, cakes
and the like we all know. It should be noted that cumarin and vanillin,