January 7, 191 5] 



NATURE 



521 



tates the addition of lead ballast. The suit consists 

 of a series of articulated sections having sliding or 

 rotating- joints, sealed sufficiently by means of leather 

 and rubber packing ; there are fifty-six of these flexible 

 joints. Roller bearings working upon steel rings pre- 

 vent jamming of the joints under high water pressure. 

 The various parts of the suit are strengthened by 

 internal and external ribbing. The diver in the Mac- 

 duffee armour breathes air at ordinary atmospheric 

 pressure, no matter how deep he goes, and this 

 differentiates the new suit from the ordinary flexible 

 diving dress. Every part of the diver is enclosed, and 

 this necessitates the addition to the dress of ingenious 

 mechanical hands operated from the interior of the 

 dress. Dangerous accumulations of water due to 

 leakage are dealt with by means of a small pump 

 attached to the dress and worked by compressed air ; 

 suction pipes lead from the pump to each foot. 



GEOPHYSICAL MEMOIRS.^ 



'PHE reproach has frequently been levelled at 

 •* meteorologists as a class that they are almost 

 entirely devoted to the accumulation of masses of 

 undigested and possibly indigestible data, but the 

 aptness of the reproach has been steadily modified 

 of late vears, and one of the chief agencies in this 

 country in producing this modification has been the 

 activity of the reconstituted Meteorological Office, 

 under the directorship of Dr. Shaw. When he was 

 awarded the Symons gold medal by the Royal 

 Meteorological Society, one of the grounds specifically 

 mentioned as influencing the council in making the 

 award was Dr. Shaw's capacity for suggesting fruit- 

 ful lines of research for other people, and the memoirs 

 contained in the volume now being completed bear 

 testimony to this contention. 



About ten years ago Dr. Shaw instituted fortnightly 

 meetings during the winter session at the Meteoro- 

 logical Office, to which he invited people interested 

 in meteorology and kindred subjects, and at which 

 definite work on such subjects was discussed and 

 freely criticised in an informal manner, and among 

 the regular attendants at these meetings for some 

 time past has been Mr. J. Fairgrieve, who, having 

 sufficient spare time, amid scholastic duties, under- 

 took the investigation which forms No. 9 of the Geo- 

 phvsical Memoirs. It is to be hoped that his example 

 will be freely followed. No. 10 is a more strictly 

 "office" production, being the continuation of No. i, 

 in which the superintendent of the Department of 

 Marine Meteorology discusses the effect of the 

 Labrador current year by year upon the surface tem- 

 perature of the Atlantic and upon the meteorology of 

 the British Isles. 



It must be admitted that a considerable proportion 

 of meteorological data is scarcely available for dis- 

 cussion, so that the first duty of the investigator is to 

 sift his material and try to introduce homogeneity. 

 For this reason pioneer work such as Mr. Fairgrieve's 

 " On the Relation between the Velocity of the 

 Gradient Wind and that of the Observed Wind," in 

 which the data are numbers estimated on the Beau- 

 fort scale, is the more valuable, in that future in- 

 vestigators are given precious hints as to what to 

 avoid, and observers may take notice of directions in 



1 Meteorological Office. Geophysical Memoir's. Vol. i., Nos. 9 and 10, 

 completing the first volume. No. 9. On the Relation between the Velocity 

 of the Gradient Wind and that of the Observed Wind. By J. Fairgrieve. 

 Pp. 189-207. 



No. 10. The Effect of the Labrador Current upon ihe Surface Tempera, 

 ture of the North Ailantic, and of the latter upon Air Temperature and 

 Pressure over the British I-Us. Part ii. By Commander M. W. C. 

 H«'pworth. Pp. 211-220. (London: Meteorobgical Office, 1914.) Price 

 IS. and $d. respectiveh 



NO. 2358, VOL. 94] 



which the form of their data can be improved. The 

 conclusions are encouraging, and the plates of illus- 

 tration interesting, although the most obvious deduc- 

 tion from them is simply that sea-winds predominate 

 at coast stations, which is scarcely novel. It is 

 evident that more work of the kind is needed, and 

 equally evident that on this subject, as on many 

 others, the proportion of chaff among the available 

 data is inconveniently high. There is a valuable 

 introductory note by Dr. Shaw, who takes the oppor- 

 tunity to print some tables of great wind pressures 

 and velocities at the British stations in the twelve 

 years 1899-1910. W. W. B. 



THE ARTIFICIAL PRODUCTION OF 

 VIGOROUS TREES. 



IN an article on the artificial production of vigorous 

 trees, contributed to the Journal of the Depart- 

 ment of Agriculture and Technical Instruction in 

 Ireland (No. i, October, 19 14) Prof. Augustine 

 Henry discusses the nature of species, varie- 

 ties, races, sports, and hybrids, as they appear to be 

 from his researches. Natural species, in the case of 

 trees, are readily recognised by the occurrence of each 

 in a definite region or habitat. We have thus one 

 species of silver fir in Central Europe, another in 

 Algeria, a third in southern Spain, etc. Of our 

 common trees — oak, birch, and elm — there are pairs of 

 species in the same region, each, however, occupying 

 a different habitat, one species adapted to a dry 

 situation, the other suited to a moister soil. The 

 pedunculate oak is a native of valleys and alluvial 

 flats. It is not protected against evaporation of 

 water, the supply of which in the ground it prefers 

 being always ample. The sessile oak is a native of 

 hilly and rocky districts, where water is not abundant 

 in the soil. Its leaves are covered beneath with hairs, 

 which guard against excessive loss of water by trans- 

 piration in windy weather. Similarly two alders 

 exist on the Continent, but only one species, Alnus 

 glutinosa, reached our islands, after the retreat of the 

 ice sheet, and before the land connection with France 

 was severed by the formation of the Straits of Dover. 

 The other species, A. incana, grey alder, is absent 

 from our native flora, but when introduced is very 

 hardy, and is useful for planting in low-lying situa- 

 tions liable to spring frosts. The ash requires such 

 special conditions of soil, that only one species exists 

 in Northern and Central Europe, there being no suit- 

 able soil for a second species to inhabit. 



A natural species is often a set of individuals 

 uniform over a large area ; but it may consist of two 

 or more "geographical varieties," which correspond 

 with distinct territories, each marked by slight differ- 

 ences of foliage, etc., that render the variety better 

 fitted for its own habitat. Thus the Corsican and 

 Austrian pines are closely related, but the latter keeps 

 its leaves two years longer on the branches, so that 

 the dense shade of its abundant foliage preserves 

 moisture in the crevices of the hot limestone rocks, on 

 which it grows in its Austrian and Servian home. 

 The Corsican pine, with half the foliage of the other 

 tree, thrives on granite soil in the moist insular 

 climate of the mountains of Corsica. These two pines 

 — only notably distinct in one character, the amount 

 of their foliage — are usually regarded as two geo- 

 graphical varieties of the same species, Piiius Laricio. 

 but by some botanists are considered to be two dis- 

 tinct species. 



In a species apparently uniform over a large area 



there may exist varieties, characterised by minute and 



I scarcely describable differences. This is exemplified 



