STEPHEN HALES (1759)
[STEPHEN HALES]
1677-1761
By FRANCIS DARWIN
An error corrected—Hales' scientific contemporaries—Physiology or Physics—Hales the Founder of the experimental method in Physiology—His style—Cambridge days—Teddington—Vegetable Staticks—Experiments described—Transpiration—Root Pressure—Assimilation—Practical application to greenhouses—Distribution of growth first measured—Hales' other activities—Sachs' tribute.
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 the life of Hales are given in my article on him 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, has to say 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 have seen the great man coming from his rooms[17] in the N.E. corner of the Great Court of Trinity—that corner where Newton's and other more modern ghosts surely walk—Macaulay who used to read, pacing to and fro by the chapel[18], and Thackeray who, like his own Esmond, lived "near to the famous Mr Newton's lodgings." In any case there can be no doubt that the genius of Newton cast its light on Hales, as Sachs has clearly pointed out (Hist. Bot., Eng. Tr., p. 477). Another great man who influenced Hales was Robert Boyle, who was born 1627 and died 1691. John Mayow again, that brilliant son of Oxford, whose premature death at 39 in 1679 was so heavy a blow to science, belongs to the same school as Hales—the school which was within an ace of founding a rational chemistry, but which was separated from the more obvious founders of that science by the phlogiston-theory of Becchers and Stahl. I do not find any evidence that Hales was influenced by the phlogistic writers and this is comprehensible enough, if, as I think, he belongs to the school of Mayow and Boyle.