June. 1911. 



KNOWLEDGE. 



233 



within which are found a series of different rock-types 

 arranged in a concentric manner. In some of these cases, 

 on the ground of field evidence, the occurrence has been 

 considered as a laccolith within which subsequent differen- 

 tiation has produced the concentric complex ; in others they 

 have been held to be stocks, or volcanic necks, in which 

 differentiation has occurred, sometimes with subsequent move- 

 ment of the differentiated bodies of magma. In the .4)Hc';-/t(r« 

 Journal of Science for .April. L. V. Pirsson and W. North 

 Kice describe a case which appears to be a laccolith, intruded 

 ■between a granitic bathylith and a cover of mica schist. 

 This is Tripyramid Mountain in Xew- Hampshire, a roughlv 

 oval mass, rising about two thousand feet above the floor of 

 the neighbouring valleys, .\roand an inner core of syenite 

 occurs a medium grained inomonite which is succeeded 

 below and outwardly by coarse-grained gabhro. Lampro- 

 phyre dykes (regarded as complementary to the syenite-aplite) 

 are situated in the peripheral gabbro and in the granite 

 against which the comple.x abuts. .\11 the rock-types in the 

 complex possess a parting or sheet-jointing parallel to a dome- 

 surface, but there is a sharp transition-line between the 

 different types and only slight endomorphic evidence of 

 contact. As to the mode of origin of the comple.x, the 

 authors do not consider the case as similar to that of 

 Magnet Cove, Arkansas, which Marker has explained as being 

 due to the doming and erosion of superposed sheets, succes- 

 sively injected. The common jointing is not in favour of this, 

 nor the relative textures of the rock types, for this view would 

 make the gabbro, which is the coarsest grained variety, the 

 uppermost sheet. The suggestion that zonal arrangement of 

 different rock-types in an intrusion may be due to absorption 

 and assimilation of surrounding country-rock is equallv 

 inapplicable in the present case. For while the country 

 rocks (granite and mica schist) are decidedly acid in character, 

 the border facies of the complex is the basic gabbro, the 

 intrusion becoming more acid towards the centre. 



While the concentric arrangement of the complex natur.illy 

 suggests a differentiation of a body of magma in place, the 

 abrupt transition of one type into another, and the occurrence 

 of syenite dykes in the monzonite. and probably of monzonite 

 dykes in the gabbro. negative this conclusion, the dykes 

 suggesting a series of successive intrusions. .Apparently what 

 best explains the phenomena at Tripyramid Mountain is a 

 process of intermediate nature, in which both differentiation 

 and repeated intrusions, separated by only short intervals, 

 took place. 



METEOROLOGY. 



By JOH.N A. Curtis. F.R.Met.Soc. 



The Weekly Weather Reports issued by the Meteorological 

 Office show that during the week ended .April 22nd the air 

 temperature was in excess of the average in all districts, by as 

 much as 4" -9 in England, N.E. and E. The extreme maxima 

 varied from 59° in Scotland X. lat Strathpeffer) to 69' in Eng- 

 land E. (at Cambridge), while the minimum fell to 27° at West 

 Linton and to 28° in the Shetlands and at Wick. Even as far 

 South as Swarraton in Hampshire a temperature of 30° was 

 reported. In the English Channel the lowest reading was 40 . 

 On the ground much lower temperatures were, as usual, 

 experienced, and at Crathes the reading was as low as 20°, at 

 Balmoral Zi°. 



Rainfall was in defect in the East and South of England, 

 but elsewhere was in excess. In Scotland N. the amount 

 collected was three times as much as usual, and in Ireland it 

 was twice as much. In England E. and S.E., however, the 

 fall was very slight and at many stations the week was 

 rainless. As a rule sunshine was less than usual. The 

 sunniest places were Felixstowe (60-6 hours, 63%) and 

 (iuernsey (61-9 hours, 55%), while Valencia had only 5-7 

 hours (6%). At Westminster the total duration of sunshine 

 was 39-7 hours (41'7„). 



The mean temperature of the sea water round the coasts 

 varied from 49° -9 at Seafield to 40' -2 at Cromarty. 



The week ended April 29th, was warm but cloudy and 



unsettled, with thunderstorms and hail. The temperature was 

 above the average in all districts, the greatest excess being in 

 England E., where it was 4°- 6 higher than usual. The highest 

 maximum, however, was 2^' lower than that of the previous 

 week, being 67° (at Cirencester) on the 23rd, as against 69° 

 (at Cambridge) on the 22nd. The lowest readings were 28' 

 at Balmoral and 30° at Nairn, but at no other stations in the 

 United Kingdom did the air temperature fall below the 

 freezing point. On the ground the temperature fell to 23" at 

 Crathes, and to 25" at Balmoral. 



Rainfall was in excess in all parts. .At several stations 

 rain was measured on e\-ery day. .At Donaghadee, on the 

 29th, there was a heavy thunderstorm wdth rain and hail, the 

 total precipitation for the day being 1-12 inches. 



Sunshine was everywhere deficient, and in some places less 

 than half the usual amount was recorded. Toniuay reported 

 the largest aggregate, 48-5 hours (49";,). At Westminster the 

 total was 35-3 hours (35%). 



The mean temperature of the sea water ranged from 40 • 7 

 at Cromarty to 50' -8 at Seafield. 



The week ended May 6th was unsettled at first but the 

 weather improved later. 



Temperature was low in most places, although the defect 

 was nowhere very great. The highest reading reported was 

 56° at .Alnwick Castle and at Raunds. Frost w-as experienced 

 in several places, the lowest readings being 28° at West 

 Linton, and 29° at Fort Augustus. The grass thermometer 

 went down to 23" at Crathes, and to 24' at Burnley. 



Rainfall was again in excess, except in England N.E. and E., 

 where it was slightly in defect, and in the Midlands, where it 

 was almost normal. In Scotland and in Ireland the rainfall was 

 very heavy, and at Fort William the total for the week was as 

 much as 3-27 inches, and at Killarney 2-34 inches. 



Sunshine was above the a\erage in England E. and S.E., 

 and in the Midlands, though below it elsewhere, except in 

 Scotland N.. where, in spite of the fact that the rainfall was 

 nearly twice as much as usual, the sunshine was 5 hours (5%) 

 in excess of the normal. Brighton reported the longest 

 duration of sunshine, 58-4 hours (57%) : at Westminster, 

 the amount was 45-5 hours (45%). 



The temperature of the sea water varied from 43° at 

 Pennan Bay and Burnmouth to 54° at Seafield. 



The week ended May 13th was fine at first, but became 

 changeable and thundery. Temperature was high throughout, 

 being in excess of the average in all districts. In Scotland 

 W. it was 6°-2 above the normal. Maxima above 70° were 

 recorded in all parts, the highest being 76 at Colmonell and 

 Greenwich. No frost was experienced, the lowest of the 

 minima being 5i°, which was reported from Geldeston Bawtrey 

 and Marlborough. The lowest temperatures on the grass were 

 27" at Kew and at Rauceby, and 28° at Greenwich. Tunbridge 

 Wells and Wisley. 



Rainfall varied a good deal in different parts of the country. 

 It was a little above the average in Scotland, and in Ireland 

 N., but was below elsewhere, and in some places very greatly 

 below. In the Midlands it was only one-third, and in the 

 English Channel, less than one-seventh of the usual amount. 

 Some heavy falls were however experienced, especially during 

 the thunderstorm on the 13th, when the rain collected at 

 York and at Rothamsted measured 1 • 2 inches, at Killarney 

 1-4 inches, and at Newton Rigg and Burnley 1-7 inches. 



Sunshine was generally above the average. England S.E. 

 was the sunniest district, with 68 hours (65%), or 21 hours 

 above the normal. Of the individual stations. Felixstowe 

 reported the largest aggregate 89-7 hours (85%), and Hastings 

 the next Largest, 82-7 hours (79%). .At Harrogate the total 

 duration was only 32 • 1 hours (30%). At Westminster the total 

 was 52-5 hours (50%i). 



The temperature of the sea water was higher on all coasts 

 than during the corresponding week of 1910. The individual 

 readings varied from 44' at Burnmouth. to 60° at Seafield. 



A balloon carrying a Meteorograph was liberated at 

 Manchester at 5.50 p.m. on March 1st and was found at Little 

 Downham, near Littleport, Cambridgeshire, having tra\elled 

 one lumdred and twenty-four miles in a south-easterlv direction 



