292 



NATURE 



[June 13, 1918 



present report, however, achieves novelty is in the 

 production, at suitable temperatures, of not only a 

 good yield of tar, but also an excellent production of 

 gas and of sulphate of ammonia. It has commonly 

 been considered that a good gas make indicates a 

 low oil production, and vice versa. The Department, 

 however, by means of a compromise on temperature 

 and by various modifications of standard gas-works 

 technique, has, without doubt, made a distinct step 

 in the direction of producing ample supplies of fuel 

 oil compatible with the maintenance of the gas output. 



In a communication to the Journal of the Rontgen 

 Society, vol. xiv.. No. 54, January, 1918, Mr. C. A. 

 Schunck describes a series of tests made to ascertain 

 the region of the ultra-violet spectrum that produces 

 the greatest therapeutic effect. The several parts of 

 the spectrum were isolated by the absorption of weak 

 solutions of quinine sulphate, salicylic acid, and 

 phenol, or by glass plates. The therapeutic effect was 

 observed by exposure of the operator's forearm to the 

 screened rays for definite periods of time, and note 

 was taken of the reaction produced. The greatest 

 effect appears in the region 2500 to 2350 A.U.; the 

 boundaries, however, of this region are not sharply 

 marked. 



Engineering of May 31 contains an account of the 

 new Trollhattan Canal, connecting Lake Vanern with 

 the Kattegat. Sanctioned by a Parliamentary vote in 

 May, .1909, the waterway in October, 1916, had 

 reached a stage which enabled it to be opened to 

 traffic, and the ceremony was performed by the King 

 of Sweden. The project is really one of old standing, 

 dating back to the days of Gustavus Vasa, who 

 initiated steps for linking up Lake Vanern with Troll- 

 hattan by means of a navigable waterway. The first 

 lock was opened in 1607. It was not, however, until 

 1800 that through connection was established to 

 Gothenburg. Various extensions have since been 

 carried out, culminating in the development called 

 the new canal, the cost of which has somewhat ex- 

 ceeded a million and a quarter sterling. The enlarged 

 waterway, which is- fifty-two miles in length, is 

 adapted for vessels generally up to 13 ft. draught, but 

 the locks, which are six in number, enabling a change 

 in level of 140 ft. to be negotiated, are constructed to 

 pass vessels of 16^ ft. draught, this being a provision 

 to meet likely developments in the near future. Each 

 of the lock-chambers has a length of 320 ft. and a 

 width of 41; ft., with a depth of 18 ft. of water over 

 sill. The canal has a mean bottom width of 79 ft. 

 The traffic during last year amounted in the aggre- 

 gate to 9759 vessels, totalling 870,668 tons. Of this 

 number 7827 were steamers, 664 sailing vessels, and 

 1268 barges. The undertaking was designed and 

 carried out under the direction of the Royal Water- 

 falls Board. 



OUR ASTRONOMICAL COLUMN. 

 KoDAiKANAL OBSERVATORY REPORT.— The report of 

 the Director of the Kodaikanal Observatory for the 

 year 19 17 has been received. The weather during the 

 year was generally unfavourable, according to Indian 

 standards, but substantial progress in many depart- 

 ments of solar research is recorded. Direct photo- 

 graphs of the sun were obtained on 294 days, mono- 

 chromatic images of the disc in K light on 328 days, 

 prominence plates on 262 days, and Ha disc plates 

 on 255 days. Judging by the mean latitude of spots, 

 it would appear that the maximum of the sunspot 

 cycle was not reached, though the northern hemi- 

 sphere may possibly have attained its greatest activity. 

 NO. 2537, VOL. TOl] 



The prominences, with a mean daily number of ig-8, 

 were in excess of those recorded in 1916; the northern 

 hemisphere continued to be more active than the 

 soutnern, as regards both prominences and spots, and 

 also as shown by prominences projected as absorption 

 markings on the disc. Work with the large grating- 

 spectrograph included the spectrum of Venus (see 

 Nature, vol. ci., p. 192), sun and arc comparison 

 spectra, and the spectrographic determination of the 

 solar rotation, in addition to experimental work on the 

 "pole effect" in the iron arc. It has been found that 

 most of the iron arc lines in the region between 4337 

 and 4494 show a tendency to shift towards the red 

 with mcreasing exposure time, indicating that they 

 are unsymmetrically widened towards the red to a 

 very slight degree. The vertical motion-shift of 

 3 km. /sec. reported by Perot for the B group of oxygen 

 (telluric lines) was not confirmed by observations made 

 at Kodaikanal. An attempt to photograph the con- 

 junction of Regulus and the sun on August 22, in 

 infra-red light, was unsuccessful, but the sky was not 

 sufficiently clear to give a satisfactory test of the 

 method. Time determinations and meteorological and 

 seismological observations were also carried on. 



Annuario of the Rio de Janeiro Observatory.— 

 The thirty-fourth issue of this useful almanac of 

 524 pages fully maintains the high standard of previous 

 years. It is divided into four sections, dealing respec- 

 tively with astronomical data for 1918, a collection of 

 tables for the reduction of astronomical observations, 

 geophysics and climatology, and a summary of 

 meteorological observations made at thirty-three 

 stations in Brazil. It is interesting to note that the 

 tables include details of the corrections to be applied 

 to the tabulated times of rising and setting of the 

 sun and moon in order to obtain the corresponding 

 data for other parts of the country; the inclusion of 

 such data in our own official almanac would doubt- 

 less be generally welcomed. Since 1660 the magnetic 

 declination at Rio de Janeiro has varied from 12° E. 

 to its present value of about 11° W., and may be 

 approximately 'represented by a formula given by the 

 director of the observatory. Dr. H. Morize, namely, 

 d = 5.6° + o-o8°t + 8o°sin(o-73°i-44-i°), where t is the 

 interval in years from 1850 taken as zero. 



ALEXANDER THE GREAT AND HIS 

 CELESTIAL JOURNEY. 



PHOTOGRAPHS were given in Nature of 

 -^ August 23, 1917, and March 14, 1918, of tradi- 

 tional rep-esentations of Alexander, seated in a car ' 

 drawn by flying griffins, from St. Mark's, Venice, 

 and Bale Cathedral, and it was conjectured that a 

 diligent hunt would reveal many similar examples in 

 Europe and England. Since then an article by Prof. 

 R. S. Loomis has appeared in the Burlington Maga- 

 zine of April and May, which shows that 'the author 

 had been engaged already in a research on the sub- 

 ject of Alexander's celestial journey. Prof. Loomis 

 gives copious references to earlier authorities, with 

 the addition of more than a score of photographs of 

 other examples of the representation, in which we are 

 pleased to find some ten are taken from English 

 churches and cathedrals, as Wells, Chester, Lincoln, 

 Gloucester (surely Canterbury), and Beverley Minster, ■ 

 Cartmel Priory, Whalley Church, St. Mary's Darling- I 

 ton, and Charney Bassett, Berks. 1 



The figure of Alexander can be recognised by the 

 two spears he carries in his hands, baited at the end 

 with a tasty lure to guide the griffins alongside to 

 bear him aloft. They are riot sceptres, or distaffs 

 even, in the mistake of the local designation (Borgo- 



