XOVEMBER, 1911. 



KNOWLEDGE. 



443 



In the land areas of the globe, calcic magmas have a 

 decided predominance over the alkalic. Mr. Harker makes the 

 interesting suggestion that this is due to the association of 

 alkaline rocks with areas of subsidence. In connection with 

 this it is remarked that the volcanic islands in the Atlantic, 

 from the Azores to Tristan d'Acunha (and, it might be added, 

 many in the Pacific) have igneous rocks of alkaline facies, and 

 conceivably belong to very extensive tracts of alkaline 

 material now submerged under the ocean. 



Mr. Harker is inclined to drop those unhappy terms 

 " Atlantic " and " Pacific," as applied to, and synonymous 

 with, the alkaline and calcic branches respectively of igneous 

 rocks. Nevertheless the distribution of types upon which 

 that nomenclature rests is regarded as none the less significant. 

 The distribution coincides not with the Atlantic and Pacific 

 oceans, but with the contrasted tectonic structures which 

 border those oceans. Consequently it is not to be expected 

 that the oceanic islands of the Pacific should necessarily have 

 igneous rocks of calcic facies : on the contrary, the dominant 

 element in their tectonics, according to Suess, being of 

 Atlantic type, the igneous rocks should be generalh' alkaline, 

 as in fact they are. The observed alkalinity of the igneous 

 rocks of Hawaii and Tahiti, therefore, instead of constituting 

 an objection, as urged by some American petrologists. con- 

 firms the simple generalization of distribution made by Harker. 

 Becke and Prior. 



METEOROLOGY. 



By John .\. Ctrtis. F.R.Met.Soc. 



The weather of the week ended September 23rd. as set out 

 in the Weekly Weather Reports issued by the Meteorological 

 Office, was at first very fine and dry, though cool, but about 

 the middle of the week there was a change, rain fell generally 

 and thunderstorms occurred. The temperature was below 

 the average in all districts, for the first time since the end of 

 June. In the North the deficit was but slight, but in the 

 Midlands and the South it was greater, reaching 3°-0 in 

 England S.E. The highest maximum was 73" at Tottenham 

 on the ISth, the next highest being 70°. reported at both 

 -Aberdeen and Guernsey, on the same day. The lowest of the 

 minima were 24" at West Linton, 25° at Balmoral and 29" at 

 Marlborough It was only at a few stations, however, that the 

 temperature fell below the freezing point. In \\"estminster 

 the minimum was 41". On the grass the temperature fell to 

 18° at Llangammarch and to 22° at Balmoral. Hereford and 

 Marlborough. Rainfall was in excess in all districts excepting 

 Scotland, E. and W. The excess was greatest in the South- 

 \\'est, where at Falmouth and other stations the total fall was 

 more than twice as much as usual. Sunshine was in excess in 

 the Central and Eastern parts of the kingdom, but w-as in 

 defect in the western districts. The sunniest stations were 

 Felixstowe and Clacton with 61 hours (71%). At Westminster 

 the aggregate was 47-2 hours (55%). At Aberdovey the total 

 was only 13-9 hours (16%). The mean temperature of the 

 sea water ranged from 51° -4 at Wick to 62° -9 at the Shipwash 

 Lightship. 



During the week ended September 30th the weather was 

 changeable and unsettled, with frequent heavy rain. Temper- 

 ature was below the normal in Scotland, England. N.W.. and 

 in Ireland, but abo\e it elsewhere. The differences, however, 

 were nowhere very large. The highest of the maxima ranged 

 from 62" at Strathpeft'er. in Scotland. E., to 72° at Geldeston. 

 in England, E.. and at Greenwich. The lowest of the minima 

 was 28" at Balmoral, on the 25th, .and only at this station did 

 the shade temperature fall below the freezing point. On 

 the grass, however, readings were in places much lower, 

 down to 21° at Llangammarch, 23° at Crathes, and 24° at 

 Balmoral. Rainfall was variable. There were some very 

 heavy falls in Ireland and Wales on the 25th: 3-00-ins. 

 at Roches Point, 2-23-ins. at Waterford, and 1-40-ins. at 

 Bettws-y-coed; but in the South there were stations where the 

 amount for the week was only -3-111. or even less. Bright 

 sunshine was above the average in all districts, most so in 



England. S.E.. where the sunniest station. Worthing, reported 

 57-6 hours (69%). The temperaf: ' ' :;ea water varied 

 from 45° at Ballantrae to 63° a: vash Lightship. 



The week ended October 7th was coid and dry, with strong 

 winds and gales in the early part. Temperature was low 

 everywhere, especially so in England. S.E., where the mean 

 was only 48° -0, compared with the average 52° -9. The 

 highest reading reported was 62° at Colmoiiell; but at the 

 majority of stations the maximum did not reach 60°. The 

 lowest readings were 2^ at Balmoral. 27° at Cally (Gatehouse), 

 and 29° at Mai-lborough. The lowest on the grass were 17° at 

 Llangammarch, 19° at Hampstead, and 20° at Balmoral. 

 Rainfall was slightly above the average in England, S.E., and 

 much above in the English Channel, where at Jersey the 

 amount collected was just double the average. The driest 

 district was Scotland. W., where Glasgow and Dumfries were 

 rainless. At Tunbridge Wells and at Canterbury there were 

 falls of over an inch on the 4th. 



Sunshine was about the average, except in Scotland. \\'.. 

 and in England. N.W., where it was in excess, and in the 

 English Channel where it was in defect. Douglas reported 

 the largest aggregate 41-0 hours 151%), while Markree Castle 

 reported the least, namely 14-0 hours (187°). The tem- 

 perature of the sea water ranged from 46° at Kirkwall and 

 Scarborough to 60° at the Shipwash and at Salcombe. A 

 pilot balloon sent up at Manchester on the 3rd August 

 was traced to a height of 25 kilometres, or more than 

 15? English miles. 



The week ended October 14th was fine generally, but with 

 a good deal of mist and fog. Thunderstorms occurred in 

 several places on the 13th. Temperature did not vary greatly 

 from the average. There was an excess in England, E., S.E., 

 and S.W., the English Channel, and Ireland. N., but a 

 deficit elsewhere. The highest readings were 68° at Green- 

 wich, Prestwich, Bettws-y-coed, and CuUompton ; the lowest 

 were 24° at Balmoral and 26° at Kilmarnock. Except in 

 England, E., and the English Channel, temperatures at or 

 below the freezing point were experienced in all districts. 

 In the English Channel the minimum was 46°. On the 

 grass the temperature fell to 17° at Llangammarch and to 

 20° at Balmoral. 



Rainfall was extraordinarily low, and in seven of the twelve 

 districts into which the country is divided for the compilation of 

 meteorological statistics, the mean amount of rainfall was less 

 than • 1 inch, and in Scotland. W.. the week was rainless. .At 

 manj' individual stations also, in other districts, the week was 

 rainless. On the other hand, at Jersey, on the 13th, 2-42 

 inches of rain fell in one day. Bright -sunshine was above the 

 average except in Scotland, N.. and in Ireland. The sunniest 

 district was England. N.W., with a mean of 40 hours (53%) ; 

 the sunniest station was Llandudno, with 51 hours (67%). The 

 lowest record for the week was 0-6 hours at Baltasound. 

 Shetlands. The temperature of the seawater ranged from 44° 

 at Ballantrae to 59° at Salcombe. 



THE SUMMER OF 1911.— In the thu-teen weeks of 

 summer ended September 2nd, the weather in England. S.E., 

 had been imusually warm in ten weeks, unusually dry in eight 

 weeks and unusually bright in nine weeks. The corresponding 

 numbers for the summer of 1910 were respecti\ely three, 

 four and one. 



INTERNATIONAL INVESTIGATION OF THE 

 UPPER AIR. — During the period. September 11th to 16th. 

 simultaneous ascents of unmanned balloons were made at a 

 large number of stations in Europe and elsewhere. The 

 co-operating stations in the British Isles were Pyrton Hill, 

 Oxon ; Ditcham Park. Petersfield ; and Manchester, in 

 England ; Crinan Harbour, in Scotland : and Mungret 

 College, Limerick, in Ireland. 



Small ballooms carrying recording instruments were dis- 

 patched simultaneously, and the return of the records and the 

 tabulation of the results is anticipated with much interest. 

 One balloon sent up at Limerick was found at Ballater, in 

 Scotland. 



