viii PREFACE.
I may add that four of the scientific men who replied to my questions have passed away since I began to write. Of these, two had sent me complete returns, namely, Professor Phillips, the geologist, and Sir William Fairbairn, the engineer. As regards the other two-Sir Henry Holland, the physician, had published his autobiography, but he gave me much help colloquially, and promised more ; and Sir Edmund, better known as Count Strzelecki, the Australian traveller and meteorologist, furnished me with very suggestive information, but too incomplete for statistical use.
FRANCIS GALTON. 42 RUTLAND GATE, November, 1874.
P.S.-I have to apologise for some faults of style in the earlier pages, due to my not having had as full an opportunity as I had counted upon of correcting that portion of the press.
After I had sent the above to the printer, <a friend happened to point out to me the fol-
