lyo 



NATURE 



[AucjusT 4, 1923 



with the influence of the ordinary forces of Nature 

 which are constantly n\odifying the animal life of a 

 country. There is a constant ebb and flow within a 

 fauna, a swing of numbers due largely to seasonal 

 changes and fluctuating about a mean — the " balance 

 of life " ; and where man's interference is temporary 

 in its incidence it falls into this category. But there 

 is, besides, a definite faunal evolution, a faunal drift ; 

 and where man's influence is persistent in one direction 

 it must be reckoned as sharing with the great secular 

 forces of Nature in propelling a fauna upon a path 

 along which there is no return. 



The nature of man's interference, directly or indirectly 

 exercised upon the animal life of Scotland, is of great 

 complexity, but it may be conveniently grouped 

 according to results. In some ways man has reduced 

 the numbers of animals, in some ways he has increased 

 their numbers, and in some ways he has modified their 

 habits and even their structures. Reduction of the 

 fauna, which, commencing with a mere cutting off of 

 the numbers of a species, may proceed to a marked 

 limitation in the range of distribution and finally to 

 extinction, has been brought about directly by deliberate 

 destruction, as in the cases of the polecat and the urus, 

 and indirectly by cultivation, which has destroyed 

 feeding grounds and breeding haunts, driving away 

 such as the great bustard and the bittern, as well as 

 by destruction of the forest, with which disappeared the 

 capercaillie and the red squirrel, both since reintroduced. 

 Increase in the quantity of the fauna is largely due to 

 an intensive cultivation which has provided bounteous 

 food-supplies for such as rabbits and sparrows, and to 

 deliberate protection of other creatures for food, sport, 

 or amenity. The quality of the fauna has been 

 increased by the addition of new elements from other 



lands, either introduced deliberately, like pheasants 

 and the common rabbit, or carried hither by mis< liance 

 of international commerce, like the black and brown 

 rats and many an insect pest. Habits liave been 

 changed : the one-time cliff-dwelling swallow has been 

 converted into an inhabitant of houses ; and structures 

 have been changed in converting wild into domesticated 

 animals, and by the alteration of habitats, whereby 

 the red deer has lost many points from its antlers 

 and several cubits from its stature. 



It must not be imagined, however, that a simple 

 enumeration of first effects exhausts the tale of man's 

 interference. The story of the effect produced, by 

 protecting a few black-headed gulls, upon the vegetation 

 of a heather moor and its fauna (which I have described 

 elsewhere) illustrates how the slightest interference with 

 wild life may produce complicated and far-reaching 

 results, and that in a remarkably short space of time. 



A final comparison of the modern fauna of Scotland 

 with that found by Azilian man on his arrival on 

 these shores, shows that the modem fauna is much 

 more rich in numbers than the old fauna, and that 

 in addition, in spite of the extermination of many 

 forms, it is also more varied in species. The consistent 

 tendency throughout the period of man's presence has 

 been for the larger animals, which formed the most 

 impressive contingent of the wild life, gradually to be 

 rooted out ; while the additions consist largely of 

 lesser creatures, many of which have gained entry only 

 because their minuteness has enabled them to escape 

 detection. The great change therefore has been a 

 notable diminution in the standard of size of the wild 

 fauna, and this tendency is still strongly marked in 

 the evolution of the Scottish fauna at the present 

 day. 



Obituary. 



Mr. S. S. Hough, F.R.S. 



MR. SYDNEY SAMUEL HOUGH, H.M. Astro- 

 nomer at the Royal Observatory, Cape of Good 

 Hope, died on Sunday, July 8, at Garrard's Cross. He 

 had visited Europe last summer and had attended the 

 meeting of the International Astronomical Union at 

 Rome, but after his return to South Africa he was in 

 poor health and ultimately cancer was diagnosed. He 

 came back to England under the care of a nurse in 

 the spring of this year and succumbed to the disease 

 after a painful illness. 



Mr. Hough was born at Stoke Newington on June 11, 

 1870. After distinguishing himself at Christ's Hospital 

 School, he proceeded to St. John's College, Cambridge, 

 as a foundation scholar. At Cambridge he had a 

 brilliant career and graduated as third wrangler in 

 1892. He was awarded the first Smith's prize in 1894, 

 and soon after was elected to an Isaac Newton student- 

 ship and to a fellowship at his college. 



After taking his degree, Mr. Hough devoted himself 

 to research work in astronomy and geophysics. It 

 had recently been found by Kiistner and Chandler 

 that the free period of the variation of latitude differed 

 from that predicted by Euler, and the investigation 

 of this subject was undertaken by Mr. Hough. He 

 passed on under the guidance of Sir George Darwin 

 to an investigation of the tides on dynamical prin- 



NO. 2805, VOL. I 12] 



ciples, and succeeded in deriving a more complete 

 solution of the tidal problem than had been previously 

 obtained, and indeed in making the most important 

 contribution to this theory since Laplace. In his 

 work he introduced the mutual gravitation of the 

 water, and he determined the periods of free oscilla- 

 tion of the ocean. At this time he also did some work 

 on periodic orbits. 



When Mr. Finlay, chief assistant at the Cape Observa- 

 tory', retired in 1898, Sir David Gill, who was then 

 H.M. Astronomer, pointed out to the Admiralty the 

 importance of selecting as his successor a man with 

 the highest scientific qualifications who might be 

 expected ultimately to become director of the observa- 

 tory. In accordance with this plan Mr. Hough was 

 selected for the post and he proceeded at once to 

 take up his duties. He became H.M. Astronomer in 

 1907. 



Mr. Hough threw himself into the work of the 

 observatory and made valuable contributions to 

 astronomy in organising and discussing observations, 

 particularly those relating to the exact positions of 

 the stars. This work is of a kind which does not 

 attract much public notice, but it is absolutely funda- 

 mental to astronomy. Soon after his arrival at the 

 Cape he was entrusted with the reduction of a tri- 

 angulation of close circumpolar stars made with the 



