72 



KNOWLEDGP;. 



February, 1911 



as to whether they are combined with the sal\'ent. so in this 

 case it is impossible to say whether the silica is present as 

 dissolved albitti or silica, or leucite, or in any other form. 

 The excess of silica which cm be taken up by nepheline to 

 form a saturated solution can apparently be determined. 

 Where albite is found iiiii::iately mixed with nepheline it is 

 evident that the nepheline must be saturated with silica, and 

 the excess of the l.uter lias formed albite. The authors 

 suggest the applic.ition of their arguments to other minerals, 

 and state that work ha.s already been begun on pyrrhotine, 

 the magnetic sulphide of iron, the formula of which is 

 variously given r.s FenSi, FctS^, and so on. In this case, 

 analyses ^■ary i'r ..ii Fes So up to FeinSn, while conforming to 

 thegeneralfonii;:: I FenSn+i(Dana's"Textbook of Mineralogy"). 



B\ 



METEOROLOGY. 



John A. Curtis, F.R.Met.Soc. 



The vv-eather of the week ended December 17th was rough 

 and squally, with high temperature and much rain. Of the 

 twelve districts into which the British Isles are divided for 

 meteorological statistical purposes, five were noted as being 

 \-ery unusually warm, six as unusually warm and only one 

 (Ireland S.I as moderate. 



The excesses above the average varied from J°-5 in the 

 English Channel to 9"-l in England E. The highest maximum 

 was 57° which was recorded at Geldeston and also at Jersey, 

 but in all districts readings of 50' or upwards were recorded. 

 The lowest readings were 30" at Strathpeffer and Nairn on 

 December 16th, but at no other stations in the British Isles 

 did the temperature fall below the freezing-point. The rainfall 

 was in excess in all districts, except Scotland N., where it was 

 but little more than half the normal amount. In England S.E.. 

 the rainfall was three and a half times as much as usual. At 

 many stations rain was measured each day, and at Llangam- 

 march Wells, the total for the week was as nuicli as 4-74 

 inches. Sunshine was generally below the average ; in many 

 places very much so. .\t Westminster, the total duration was 

 2-9 hours, or 5%. At Greenwich it was 67 hours or 12",,. 

 There was much strong wind during the week, and on the 15th 

 there was a severe and widely-spread gale. The temperature 

 of the sea water varied from 51° at Salcombe to 41° at 

 Cromarty. 



The week ended December 24th was mucli drier th.m those 

 which had preceded it; still rain fell frequentl>', and at several 

 stations on every day. The aggregates were less than the 

 average in all districts except Scotland N., where it was 

 double the usual amount. In England N.E., the rainfall 

 amounted to only 0-08 inches, or less than one-sixth the 

 normal. Temperature continued high, and there was excess 

 in each district, as much as 5-0 in Scotland E. The highest 

 reading recorded was 57°, but in all districts readings of 53° 

 and upwards were recorded. The lowest minimum was 27°, 

 at Swarraton, Hants. Bright sunshine was also in excess 

 generally, though some curious anomalies were reported : thus, 

 for instance, at Birr Castle the total duration was 8'2 hours in 

 excess, while at Dublin it was 7'0 hours in defect. The mean 

 temperature of the sea water was higher than in the corres- 

 ponding week of last year by as much as 5° at some stations. 

 The individual readings ranged from 51° at Salcombe, to 40 

 at Pennan Bay and at Cromarty. 



The weather of the last week of the year was imsettled, but 

 there were bright periods in most parts, and several dry days. 

 Temperature was rather above the average as a rule, and 

 readings of 50' or above were recorded in all districts except 

 Scotland E. The highest maximum observed was 53° at 

 Killarney and at Jersey, while on the other hand the lowest 

 recorded was 18° at West Linton, on the 28th, and 19° at 

 Llangammarch Wells on the same day. On the grass the 

 temperature fell to 8° at Llangammarch Wells, to 15° at 

 Tunbridge Wells and to 16° at several places. Rainfall was 

 scanty except in Scotland N., the amounts in many places being 

 one-fourth or less of the average ; at Leith the total for the week 

 was only Q-Ol inch. Sunshine was generally in excess, and 

 the largest aggregate recorded, namely 25'3 hours, at Hastings, 

 was 47% of the possible duratiem. On the other hand, at 



Westminster the total duration was only 2-7 hours or 5 %. 

 The sea temperature showed a considerable decrease as 

 compared with the previous week and ranged from 50" at 

 Scilly and Plymouth to 39° at Cromarty. 



The weather during the first week of 1911 was generally 

 dull .aid wet, except in the North-West, where it was dry and 

 fine. Temperature was below the average, except in England, 

 N.E., where it was 0°-2 in excess. The defect was, however, 

 as a rule, not of great amount. Individual readings exceeded 

 50° in most districts, and in Ireland S., on the 7th, 52° was 

 reported, both at Killarney and at Valencia. Frost was 

 experienced in all districts except the English Channel. The 

 lowest of the minima were 16° at Balmoral. 20° at Nairn, 

 West Linton, and Strathpeffer, and 21° at Birr Castle and 

 Cahir, in Ireland S. The readings on the grass were as low 

 as 9° at Llangammarch Wells, and 14' at Balmoral. Rainfall 

 was above the average in England N.E., E., and S.E., but 

 was deficient elsewhere. In Ireland S., the aggregate fall 

 was but little more than half the usual amount. Sunshine 

 was, as usual, greatest where rainfall was least; the percentages 

 of its possible duration ranged from 14% in England, N.E., to 

 37% in Ireland N. At Westminster the total duration of 

 Sunshine for the week was only 0'6 hours. At .\berdovey it 

 was 2Z'2 hours. A severe thunderstorm, accompanied by 

 snow and hail, was experienced in Norfolk during the early 

 hours of January 2nd. 



The week ended January 14th was unsettled, with rain during 

 the earlier days and sleet and snow later. Temperature was 

 below the average in England S.W., English Channel, and in 

 Ireland, but abo\e it elsewhere. The departures from the 

 mean, however, were not large. The highest reading was 

 54 at Killarney on the 8th, and temperatures of 50° or upwards 

 were reported from each district. The lowest minimum was 

 22 .at Kilmarnock and at Cally, Gatehouse, on the 13th. At 

 several other stations the readings were below 25°. On the 

 grass the temperature fell to 12° at Newton Rigg. and to 14" at 

 Tunbridge Wells. Rainfall also was not far from the mean, 

 being below it in the Midlands, England S.W. and in Ireland ; 

 e(iual to it in England N.W.. and above it in the other districts. 

 The heaviest fall was on the 10th when 1'36 inches fell at 

 Poltalloch, 1-17 inches at Fort William, and 1-04 inches at 

 Aspatria. Sunshine was in excess in all districts except Scotland 

 N., where it was slightly in defect. The greatest divergence from 

 the mean was in England S.W., where the district value for 

 duration was 17 hours as compared with an average of 10 hours. 

 ,'\t Westminster the aggregate was 8T hours (15%) ; at 

 Falmouth 23'8 hours (42%). A thunderstorm occurred at 

 Newcastle-on-Tyne on the 12th. Aurora was seen in Scotland 

 on the 8th. The temperature of the sea water varied from 

 49 at Scilly and Plymouth to 36" at Cromarty. 



THE RAINFALL OF 1910.~Dr. H. R. Mill, of the British 

 Rainfall Organization, has an interesting article in the last 

 number of Sv;;K)«s's Meteorological Magazine upon the Rain- 

 fall of the past year. The year was a wet one in nearly all 

 parts of the Kingdom. The principal parts of the country 

 having less than the average amount were Western Ireland 

 (Counties Galway, Mayo, and part of Clare) ; Western Scotland 

 (.Argyll and the Western islands), South-Eastern Scotland 

 and North-Eastern England; and a narrow strip on the coast 

 of South Wales. Each country, however, had an excess, 

 England and Wales of 11%, Scotland 2%, and Ireland 9%. 

 For the British Isles, as a whole, the excess was 8%, 

 February was the wettest month, with 61% excess, and 

 September was the driest month, with 69% defect. 



September, 1910, was one of the driest Septembers on 

 record, and February was one of the wettest Februaries. 

 The total rainfall for the ten months, January to September, 

 was almost exactly equal to the average fall for the whole 

 \'ear. 



Since 1889 there has been a marked sequence of two dry 

 years followed by one wet year, but this relation has now 

 broken down, and we have had two wet years in succession. 

 Dr. Mill adds: "It seems possible that the swing of the 

 pendulum is carrying us into a period of predominating wet 

 years, corresponding to the wet period of 1874-1883," 



