March 27, 1919] 



NATURE 



73 



(130 ft.) above the ground at its highest point. Bv 

 lowering the water-level two metres, a supply of 

 5,000,000 cubic metres (say 1,100,000,000 gallons) will 

 be available, which is sufficient to equalise load varia- 

 tions during a period of twenty-four hours. The 

 dam will be designed as a composite structure, with 

 special features to resist ice-pressure, which is, of 

 course, a vital consideration in such high latitudes. 

 The aggregate surface area of all the lakes within the 

 catchment area amounts to about 890 sq. Ion. 

 (343 sq. miles), and the total catchment area to 

 c]ii86o sq. km. (3805 sq. miles). 



OUR ASTRONOMICAL COLUMN. 



Venus and Jupiter.— The planets Venus, Jupiter, 

 and Saturn are now finely displaved in the evening 

 sky. Venus is situated in Aries, 'Jupiter in Gemini, 

 and Saturn in Cancer. To the naked eye a verv 

 interesting spectacle will be afforded during the en- 

 suing few weeks by the approach of Jupiter and 

 Venus. At present they are distant about 60° from 

 each other, but this interval is decreasing at the rate 

 of slightly more than 1° each night. This is due to 

 the easterly movement of Venus. It will prove an 

 entertaining incident to watch the gradual approach 

 of the two planets until their conjunction on the night 

 of May 25, when they will be very little more than 

 2° distant from each other near 'the time of their 

 setting at about 11. 11 p.m. 



Comets of the Jovian Family.— Schorr's comet 

 (d 19 18) adds another member to the ever-increasing 

 group of short-period comets. Forty of these objects 

 were previously known, but fewer than half of this 

 number had been fully confirmed by observations of 

 a second return to perihelion. Two' orbits have been 

 computed for Schorr's comet which differ in the 

 period assigned, one giving 673 years and the other 

 5-86 years. Definitive elements will, no doubt, be 

 calculated when the comet has passed beyond the 

 range of further observations. 



Star Clusters.— Dr. C. V. L. Charlier has made 

 an investigation of the distances and configuration of 

 clusters (Meddelanden, Lund Observatory, ser. ii., 

 No. 19). Making the simple assumption that distance 

 varies inversely as angular diameter, he finds a 

 grouping of the non-globular clusters strikingly 

 similar to that which he found some years ago for the 

 B stars. This is a satisfactory confirmation of the 

 previously accepted conclusion that the non-globulars 

 are intra-galactic objects. Since the centres of the 

 two systems (non-globulars and B stars) are in the 

 same direction from the sun, it is a reasonable 

 assumption that they are coincident, which . enables 

 the scale of the non-globular system (at first left 

 arbitrary) to be determined. A second determination, 

 fairly accordant with the first, is made by assuming 

 the extent of the system in a direction perpendicular to 

 the plane of the galaxy to be the same as that found for 

 the B stars. In the galactic plane the distances range 

 to 5000 L.Y., but the great majority are less than 

 3000. The greatest co-ordinates perpendicular to the 

 plane are about 1600 L.Y., indicating the usually 

 accepted bun-shaped figure. It is evident that the 

 distances of individual clusters cannot be relied on, 

 but it is interesting to note that the distance of the 

 great double cluster in Perseus comes out as 400 L.Y., 

 which is close to the distance deduced for Nova Persei 

 from the rate of illumination of the surrounding 

 nebula. 



Treating the globular clusters in the same way. Dr. 

 Charlier finds a configuration similar to that found 

 by Dr. Shapley, but on the question of scale he is in 



NO. 2578, VOL. 103] 



strong opposition to him, insisting on the intra- 

 galactic situation of the globulars, owing to their 

 concentration in the great star-cloud of Sagittarius, 

 and other features of their grouping. He is thus led 

 to take the absolute magnitude of the brightest cluster 

 stars as about +8, and to assert that the cluster 

 variables are dwarfs, though the Cepheids with their 

 similar light-curves are admittedly giants. Prof. 

 Eddington's researches make it unlikely that stars of 

 small mass could attain a sufficient temperature to 

 have a negative colour-index, such as Dr. Shaplev 

 found in many of the cluster stars. However, the 

 results of the latter are of such a startling and far- 

 reaching character that it is all to the good, in the 

 interests of the attainment of truth, that an 

 astronomer of Dr. Charlier's eminence should hold a 

 brief for the other side pending further light on some 

 of the weaker links in Dr. Shapley 's chain of 

 reasoning. 



WEATHER INFLUENCES ON THE WAR. 

 pROF. ROBERT DE C. WARD contributes an 

 ■*■ article on ' Weather Controls over the Fighting 

 during the Autumn of 1918" to the Scientific Monthly 

 for January. This is the concluding communication 

 of a series which has from time to time been noticed 

 in Nature, and deals with the weather to the time 

 of the signing of the armistice by Germany. The 

 author states his belief that "as a part of the scientific 

 history of the great war, as full an account as 

 possible should be kept of the meteorological condi- 

 tions which affected the operations on all the battle- 

 fronts." 



The autumn of 1918 is stated to have been " in 

 many respects the most critical season, meteoro- 

 logically, of any period of equal length during the 

 whole war." It was clear that the .Mlies were deter- 

 mined to force the defeat of the Germans whilst 

 fighting weather lasted. The Allies, by pushing on, 

 were gaining better ground and more shelter for their 

 armies. 



At the commencement of September despatch <- 

 mentioned the "unprecedented dryness" which fc 

 about a week favoured the movements of the Allien, 

 but the second week of September experienced heav\ 

 storms, which retarded progress. Throughout the 

 war as autumn advanced the fighting conditions were 

 less favourable, and the Flanders mud had proved an 

 almost insurmountable obstacle. The distribution of 

 the rainfall throughout the year at the Western Front 

 is similar to that over the south-east of England, 

 where the heaviest rains occur in the autumn season, 

 the average rainfall of October being equal to that 

 of February and March combined. Add to these 

 conditions the drop of temperature, which on the 

 Continent is much greater than in the British Isles, 

 and the colder weather brings more snow and slush. 

 The rivers are not uncommonly in flood, and, wherever 

 possible, the enemy caused artificial flood, hampering 

 and impeding the movements of the Allies. 



Official despatches laid unusual stress on the un- 

 favourable weather controls of the autumn, but 

 probably much of this was due to the intense anxiety 

 of the Allies to crush the eneniv before winter set in. 

 .All bad weather was helping the enemy by delaying 

 attack and enablinj* him to organise his retreat. Thi» 

 Monthly Weather Report of the Meteorological Office 

 for September shows that the month was abnormally 

 wet and very cold, whilst in many parts of Englan<l 

 "the rainfall totals were the greatest ever measured, 

 not only in September, but in any calendar month 

 whatever." The map showing the movements of 



