the circles are three-quarter black; this means
that a very minute crack is left open.

It is important to remember that each pipe has its individuality. For
instance, in one of my instruments G must have the thumb hole completely
open, and the alternate fingering (with the index hole closed) is quite
out of tune. The note E is sometimes sharp; in the pipe, the fingerings
of which are given in fig. 6, this fault is corrected by means of a thin
metal lining to the lower hole.

VIII
STEPHEN HALES {115}
1677-1761

In attempting to give a picture of any man's life and work it is well to
follow the rule of the _Dictionary of National Biography_, and begin with
the dates of his birth and death. Stephen Hales was born in 1677 and
died in 1761, having had experiences of the reigns of seven sovereigns.

The authorities for his life are given in my article on Hales in the
_Dictionary of National Biography_. Botanists in general probably take
their knowledge of the main facts of his life from Sachs' _History of
Botany_. It is therefore worth while to point out that both the original
and the English translation (1890) contain the incorrect statement that
Hales was educated at Christ's College, Cambridge, and that he held the
living of Riddington, whereas he is one of the glories of Corpus, and was
perpetual curate of Teddington. These inaccuracies, however, are trifles
in relation to the great and striking merits of Sachs' _History_, a work
which, to my thinking, exhibits the strength and brilliance of the
author's mind as clearly as any of his more technical writings. Sachs
was no niggling biographer, and his broad vigorous outlines must form the
basis of what anyone, who follows him, can write about the botanists of a
past day.

To return to Hales' birth. It is of interest to note how he fits into
the changing procession of lives, to see what great men overlap his
youth, who were his contemporaries in his maturity, and who were
appearing on the scientific stage as he was leaving it.

Sir Isaac Newton was the dominant figure in English science while Hales
was developing. He died in 1727, the year in which Hales published his
_Vegetable Staticks_, a book, which like the _Origin of Species_,
appeared when its author was 50 years of age. Newton was at the zenith
of his fame when Hales was a little boy of 10--his _Principia_ having
been published in 1687, and when Hales went up to Cambridge in 1696 he
must h