44 



NATURE 



[July m, 1910 



The paper includes useful tables giving the pres- 

 sure and the density at different heights, the variation 

 of temperature on surfaces of equal pressure, and the 

 temperatures in different quadrants of cyclones and 

 anticyclones. 



It is full of interest, and stands as an example of 

 the "thorough" policy of Prof. Hann, to whom, 

 indeed, it would not do discredit. E. Gold. 



THE GULF STREAM DRIFT AND THE 

 ]VEATHER OF THE BRITISH ISLES. 



ALTHOUGH it has been known for very many 

 years that the climate of these islands and of 

 northern Europe generally is far milder than it would 

 otherwise have been owing to a large body of warm 

 water flowing past its shores from the south-west, 

 it is only within recent years that attempts have been 

 made to trace any detailed connection between the 

 state of the Gulf Stream Drift ' and the weather. 



Now that systematic hydrographic observations 

 have been accumulating for a number of years it is 

 becoming possible to attack seriously this interesting 

 problem, and the results so far obtained certainly 

 look promising. 



The immediate causes of the weather in the British 

 Isles are undoubtedly to be sought in the various 

 atmospheric disturbances which arrive from the 

 Atlantic, but there can be no doubt that another 

 very important factor to be considered is the tem- 

 perature of the adjacent seas. This is influenced by 

 the Gulf Stream Drift. 



The problem is, however, complicated by the fact 

 that there is some doubt as to whether the Gulf 

 Stream Drift may not be a direct result of the atmo- 

 spheric circulation in the huge cyclonic system which 

 rests over the North Atlantic, with its centre at Ice- 

 land. 



Be that as it may, there is undoubtedly a very 

 intimate connection between the oceanic and atmo- 

 spheric circulations in the North Atlantic region, so 

 that if the atmospheric circulation becomes more 

 vigorous, the Gulf Stream Drift moves faster, and 

 vice versa. This is well shown in a paper by 

 Meinardus in the Meteorologische Zeitschrift, xxii., 

 398, 1905. Such a connection was, however, to be 

 expected, not only if the Gulf Stream Drift were 

 directly due to the atmospheric circulation, but also 

 if, as seems more probable, both were due to the same 

 cause, namely, the excessive cooling at the poles of 

 the earth, coupled with the rotation of the earth about 

 its axis. On this view both the oceanic and atmo- 

 spheric circulations are of the nature of convection 

 currents, and primarily due to the same cause, but 

 in the course of ages these two distinct circulations 

 have so adjusted themselves that any change in the 

 one rapidly causes a corresponding change in the 

 other. 



It seems probable, therefore, that the Gulf Stream 

 Drift, owing to its inertia and its great heat capacitv, 

 should have a similar effect to that of the flywheel 

 of an engine, and lend to obliterate the disturbances 

 due to the more unstable and variable atmospheric 

 circulation. In this case the Gulf Stream Drift should 

 have a very considerable regulating influence on the 

 aeneral tvpe of weather prevailing in the British 

 Isles. 



Let us consider the probable influence on the tem- 

 perature and on the rainfall. In the winter the 

 temperature of the Gulf Stream Drift is higher than 

 that of the land, while in the summer it is lower. 



1 The varm water flowin 

 le called the Gulf Stream, 

 o extend further east than '. 

 ) Europe is kr 



! round the British U\, 

 The Gulf Stream prop 

 ilewfouTidland, while it 

 own as the Gulf Streai 



> to Scandinav a used to 

 r is now considered not 

 fan-like extension which 



NO. 2124, VOL. 84] 



Consequently during the winter time the winds blov;- 

 ing from the Atlantic tend to raise the temperature 

 of the land, while in the summer they tend to lower 

 it, and it is clear that variations in the temperature 

 of the Drift must be expected to affect the tempera- 

 ture of the winds blowing over it, and consequently 

 the temperature on land as well. Such effects on the 

 land temperature will probably be far more important 

 in the winter than in the summer, owing to the rela- 

 tively greater power of the solar radiation during the 

 summer. 



The effect on the rainfall will be equally marked, for 

 the amount of inoisture carried by the winds and 

 available for precipitation as rain depends largely upon 

 the temperature of the sea over which they have 

 blown. The warmer the sea the more moisture is 

 taken up and the more precipitation may be expected 

 on the neighbouring land. 



In this way, for instance, it is possible to account 

 for the low rainfall last year in the western parts of 

 Great Britain and Ireland — parts which are usually 

 very wet — for during 1909 the temperature of the Gulf 

 Stream Drift was below the normal, and hence the 

 winds blowing from it were not so heavily charged 

 with moisture as usual. 



The somewhat lower land temperature seems to have 

 just about compensated for this by the time the winds 

 reached the east of Great Britain, so that the rain fell 

 there instead of in the west. The result of this was 

 an abnormally high rainfall in the east, and with the 

 low one in tlie west the rainfall over the British Isles 

 as a whole was exactly equal to the average. 



It will be very interesting to see if this is what may 

 be generally expected in years when the Gulf Stream 

 Drift is weaker than usual. 



There is clearly a possibility of being able to predict 

 the general character of the weather in these islands 

 several months in advance from the results of hydro- 

 graphic observations. It is, of course, a very complex 

 question, and at present one cannot be too confident, 

 but I am certainly of the opinion that =.uch predic- 

 tions will be possible. 



In another place I have thrown out the suggestion 

 that, as the February hydrographic observations made 

 in the Irish Sea this year were almost identical with 

 those of last year, there was some probability that the 

 weather during 1910 would be somewhat similar to 

 that of last year. It was never expected that the sug- 

 gestion would attract the attention it has done, but it 

 is interesting to note that the May hydrographic 

 observations are also very similar to those of last 

 year — if anything, even less favourable. 



H. Bassett. 



PROF. G. V. SCHIAPARELLI. 



PROF. SCHIAPARELLI, whose death we briefly 

 announced last week, for many years occu- 

 pied a prominent position in the world of science. 

 Half a century has passed since he began his career 

 as second assistant in the Brera Observatory of 

 Milan, and nearly as many since he was elected to 

 fill the position of director. In that position he 

 exhibited much energy, and increased the reputation 

 of the observatory. But his greatest success came 

 to him early, and though he worked long and dili- 

 gently, giving evidence of patient industry and prac- 

 tical skill as an observer, he will be remembered 

 mainly for having satisfactorily established the con- 

 nection between meteors and comets. It was a bril- 

 liant discovery founded on acute penetration and 

 sound reasoning. It was, moreover, a discovery that 

 the public were able to appreciate, and by popular 

 applause he was lifted at once into the front rank 



