I20 



NATURE 



[October 9, 19 19 



Shanklin and also at Ross-on-Wye, and " reddish- 

 yellow " at Newquay. 



The display was hrst noticed at Bristol at 9.15, and 

 the final traces of it disappeared 5I hours afterwards, 

 viz. at i5h. G.M.T. The appearance was that of a 

 band of luminosity lying just over the northern region 

 of the sky and extending over about 70° from nearly 

 north-west to north-east. From this intense glow- 

 streamers occasionally shot upwards, but these quickly 

 broadened ;ind disappeared. They showed a reddish 

 tint, and in several cases could be traced nearlv to 

 the altitude of Polaris. The stars of Ursa Major were 

 deeply involved in the aurora, but shone conspicuously 

 amid the light surrounding them. 



.\t first sight a person might have mistaken the 

 aurora for the rejection of a widespread conflagration, 

 but a little watching revealed the precise nature of 

 the event. Clouds covered a large portion of the skv 

 at times, but it seemed curiously to avoid the region 

 affected by the phenomenon, and there were showers 

 of rain at intervals. The brilliancy of the northern 

 light and the darkness of the clouds in other parts 

 offered a striking contrast. Several meteors were seen 

 during the night radiating from a point at 355° + 40°. 



A letter from the Isle of Man describes a brilliant 

 aurora visible there at 8.45 G.M.T. on the same night, 

 and continuing with various modifications for several 

 hours. 



Dr. C. Chree has supplied the following note en 

 the simultaneous magnetic storm as recorded at Kew 

 Observatorv, Richmond : — 



'■.\ smart magnetic storm was simultaneouslv 

 experienced in connection with the aurora. .'\s 

 recorded at Kew Observatorv, it began with a well- 

 marked S.C. (sudden commencement) about i6h. 12m. 

 G.M.T. on October 1, and continued until 4h. on 

 October 2. The approximate ranges were 32' in D, 

 2807 in H, and 1707 in ^'. The extreme westerlv 

 position was reached at the end of the S.C. about 

 ■i6h. i6m., the extreme easterly position about 

 23h. 25m. on October i. Between 22h. i8m. and 

 22h. 50m. there was a swing of 29' to the east. The 

 maximum in H appeared about i7h., the minimum 

 shortly before midnight. .'Xfter the minimum there 

 was a rapid recovery from the depression. .\s usual 

 in storms, V was enhanced in the afternoon, the 

 maximum appearing about igh. lom. There was, 

 Tiowever, a second approximatelv equal maximum 

 about 22h. 15m. This was preceded and followed bv 

 somewhat rapid movements. ."Vfter 23Jh. there was 

 depression in V, the minimum appearing shortlv after 

 midnight. The element remained depressed until 4h. 

 on October 2. The curves were fairly quiet for the 

 next twenty-four hours, but disturbance began cgain 

 about 4h. on October 3, and was active when the 

 sheets were changed about Joh. It mav be noted here 

 that the storm itself was quite secondary as compared 

 with the big one in August last, and so, from the 

 purely magnetic point of view, the interest is very 

 moderate." 



THE SUDAN IRRIGATION WORKS. 



T T is an unfortunate circumstance when a con- 

 ■^ troversy respecting the merits of rival schemes 

 for Imperial development works is embittered bv 

 charges impugning the good faith of either side, and 

 It is particularly painful when an accusation of this 

 kind is levelled by a Government official of high 

 standing and repute against his colleagues in the 

 Department with which he was formerly associated. 

 We do not propose to discuss the ethical question (it 

 has alreadv been the subject of inquiry by a Foreign 



NO. 2606, VOL. 104] 



Office Committee), but it is unavoidable to mention it 

 as indicating the ground upon which Sir William 

 VVillcocks has published his brochure on "The Nik- 

 Projects" and the acutely critical spirit in which it 

 is written. 



We have already outlined in N.mure for September 18 

 (p. 67) the schemes actually adopted by their respective 

 Governments, and now in course of executionj for the 

 development of irrigation in Egypt and the Sudan, 

 comprising the formation of a dam on the Blue Nile at 

 Makwar, near Sennar, and of a reservoir at Gebel-el- 

 .\uli, on the White Nile; and in the "Notes " columns 

 of the issue for .May 22 last (p. 233) we briefly alluded 

 to the alternative proposal advocated by Sir W. Will- 

 cocks and designated by him "the .Sudd reservoir." 

 The following additional particulars gleaned from the 

 pamphlet before us may be of some interest. 



The Blue Nile project, for the irrigation of the 

 Gezirah plain in the Sudan, involves the storage of 

 463,000,000 cubic metres of water for distribution 

 during the winter season to 300,000 fcddans (acres) 

 about to be exploited in cotton-raising. To meet this 

 requirement a supply of 120-150 cubic metres per 

 second will be necessary at the canal head throughout 

 the winter up to the end of .March, although in an 

 occasional year the supply may have to be continued 

 to the middle of .-\pril. This would leave three months 

 for thq gathering of the crop and the preparation of 

 the ground prior to the next sowing. It is essential 

 to have this period as dry as possible in order to 

 root out the old stalks, \yhich otherviise tend to 

 sprout, as, indeed, happens when the rains supervene. 

 Sir W. Willcocks expresses the apprehension that 

 irrigation supplies will have to be given much later 

 than .-\pril 15, and that the sources for Egyptian use 

 will be seriously depleted in consequence. 



The White Nile reservoir at Gebel-el-.^uli, pro- 

 posed to be formed by an earthen bank across the 

 river at a point some 50 km. above Khartoum, comes 

 in for the criticism that it will flood a considerable 

 tract of country, disturbing the inhabitants and neces- 

 sitating their transfer elsewhere, and that the stag- 

 nant pools left when the reservoir is low will lead 

 to an increase in mosquitoes. Both these objections 

 were before the Foreign Office Committee, but were 

 not held to be vital. -Another point made by Sir W; 

 Willcocks is that a work so remote from Egypt might 

 in the hands of a hostile Power become a serious 

 menace to that country. ".An enemy getting posses- 

 sion of the dam and filling it brimful to the height 

 of the earthen bank in a high flood could sweep the 

 Nile Valley as thoroughly as Noah's deluge swept the 

 Euphrates Valley." 



Pursuing a trenchant criticism of the estimated cost 

 of the foregoing schemes. Sir W. Willcocks compares 

 them very unfavourably with his own project of 

 utilising as a reservoir the vast tract of swamp known 

 as the Sudd region, where, owing to the dense growth 

 of papyrus and aquatic vegetation, there are "a score 

 of milliards of cubic metres of water standing well 

 above the level of the flat plain as though they were 

 congealed." Such a region. Sir William contends, 

 could be laid under contribution for practically in- 

 exhaustible supplies of water more effectively and at 

 less cost. Brysson Cunningham. 



COLLIERY BOILER-PLANTS. 



A REPRINT of articles on the performance of 

 **• colliery steam boiler-plants and the saving to 

 be obtained by their reorganisation, which appeared 

 in Engineering for July 25 and .August 1 last, has 

 been sent us bv the author, Mr. D. Brownlie. The 



