NA TURE 



[March 22, 1906 



(if economic value met with include iron ores, mica, copper 

 ores, manganese, rutile, as well as limestone and other 

 building stones. 



It has always been a difficult matter to obtain pure 

 lithium by the electrolysis of fused lithium chloride, which 

 has been the method employed up to the present, and was 

 originally used by Bunsen. In the Zeitschrift jur Elektro- 

 chemie of March 9, Messrs. O. Ruff and O. Johannsen 

 describe a process which they have satisfactorily worked 

 out for its preparation by the electrolysis of lithium 

 bromide. They prepare the lithium bromide by the action 

 of hydrobromic acid on the carbonate. The electrolysing 

 vessel is of copper, and is partially water-jacketed in order 

 that the walls may be kept cool and thus protected by 

 a coating of solid lithium bromide. The anode is of re- 

 tort carbon, and the two kathodes of iron wire 4 mm. in 

 diameter. The electrolyte consists of lithium bromide con- 

 taining 15 per cent, of lithium chloride. A current of 

 100 amperes at 10 volts is employed, and the yield of 

 metallic lithium is about So per cent, of the theory. From 

 time to time the metal as it collects on the iron kathode 

 is removed with a flat iron spoon, and at once placed on 

 a cold stone surface, where it rapidly solidifies. Determin- 

 ations of the melting point showed it to be iSo°, which 

 agrees with that found by Bunsen in the middle of the last 

 century. 



A simple arrangement for purifying mercury which is 

 likely to prove of considerable service is described by 

 Messrs. G. A. Hulett and H. D. Minchin in the Physical 

 Review (vol. xxi., No. 6). The method consists in dis- 

 tilling the mercury in a W'urtz flask under diminished 

 pressure, allowing bubbles of air to pass through the 

 mercury during distillation so as to prevent bumping. 

 The air also serves the very useful purpose of oxidising 

 any metallic impurity, such as zinc, cadmium, or lead, 

 which otherwise would contaminate the distillate. 

 Ordinary distillation in vacuo of mercury containing one 

 of these metals does not suffice to remove the impurity, 

 but by using the method described an amalgam of zinc 

 can be made to yield pure mercury in a single distillation. 

 An electrical method of ascertaining the presence of one 

 pan of zinc in ten billion parts of mercury is described 

 incidentally. 



The March number of the Geographical Journal contains 

 an interesting table by Miss Nora E. MacMunn, compiled 

 from planimetric measurements made on an orographical 

 map at the School of Geography, Oxford, showing the 

 areas of the orographical regions of England and Wales. 

 As a rule, the plains have been measured to the 250-feet 

 contour line, and the hills have not been considered to 

 begin below that level. The average height of England 

 and Wales, calculated from these measurements, is 385 

 feet. Of the total 58,324-3 square miles constituting the 

 area of England and Wales, 26,481-6, or 45 4 per cent., are 

 under 250 feet in elevation ; 16,364-5, or 28 per cent., are 

 between 250 feet and 500 feet; 10,4703, or 18 per cent., 

 are between 500 feet and 1000 feet; 46983, or 8 per cent., 

 are between 1000 feet and 2000 feet ; 3000, or 05 per 

 cent., are between 2000 feet and 3000 feet ; and 3-6 are more 

 than 3000 feet above sea-level. 



Mr. Frowde is about to publish for the Radcliffe trustees 

 a " Catalogue of 1772 Stars, chiefly comprised within the 

 Zone 85°-9o° N.P.D., for the Epoch 1900," deduced from 

 observations made at the Radcliffe Observatory, Oxford, 

 during the years 1894-1903, under the direction of Dr. 

 A. A. Rambaut, F.R.S. 



NO. 1899, VOL - 73] 



OUR ASTRONOMICAL COLUMN. 



Discovery of a New Comet (1906c). — A telegram from 

 Kiel announces the discovery of a new comet by Mr. Ross, 

 of Melbourne, on March 18. 



Its position at 7h. 36-im. (Melbourne M.T.) was 

 R.A.=2h. 3m. 52s., dec. = —7° 41', 

 which is about half-way between ( and o Ceti. 



A second telegram from Kiel states that Mr. Morgan 

 observed the comet at Glasgow (U.S.A.) on March 19. Its 

 position at 7h. 409m. (Glasgow M.T.) was 



R.A. =2h. 9m. 3I-4S-, dec. = —5° 47' 25". 



The comet is stated to be of about the eighth magnitude. 



Comet 1906b. — Numerous observations of comet 19066 

 are reported in No. 4078 of the Astronomische Nachrichten. 



Observing at Bamberg on March 4, the day after its 

 discovery, Prof. Hartwig found that the comet had a 

 diameter of about 10" and a central condensation of about 

 magnitude no. The same magnitude was recorded by 

 Dr. Wirtz at Strassburg on March 6. 



Prof. Max Wolf reports that the comet is easily seen 

 on his plates, and shows a tail of about half a degree in 

 length ; with the 10-inch refractor a sharp nucleus was 

 observed on March 4, and it was seen that the tail extended 

 to the north-west. 



Comet 1906a (Brooks). — In No. 4078 of the Astrono- 

 mische Nachrichten Heir M. Ebell gives a further daily 

 ephemeris for comet 1906a, extending from March 16 to 

 M.i\ 3. The following is an extract therefrom : — 

 Ephemeris 12I1. M.T. Berlin. 

 1006 a (true) 8 (true) log r log A Bright- 



Mar. 20... 5 41 5 ... +46 31 ... 0-2618 ... 0-1986 ... 0-25 

 24 ... 5 42 18 ... +43 47 ... 0-2710 .. 02284 ■■- o'2i 

 28 ... 5 43 58 ... +41 23 ... 0-2801 ... 0-2567 ... 018 

 April 1 ... 5 45 57 ... +39 18 ... 0-2891 ... 0-2835 ■■■ ° '5 

 5 ... 5 48 jo ... +37 27 ... 0-2981 ... 03088 ... 013 

 9 ... 5 50 34 ... +35 4S .. 0-3069 ... 03325 ... o-il 

 Brightness on January 27 = i-o = about 10-0 m. 

 Observing at Arcetri on January 31, Dr. Abetti found 

 that the comet had a central nucleus of about the tenth 

 magnitude or a little greater, and that the surrounding 

 nebulosity extended for about 2', chiefly towards the direc- 

 tion of lesser right ascension. 



On March 22 this comet will pass near to /3 Aurigae, 

 about um. (R.A.) to the west, whilst on April 5 it will 

 be only about 5m. west of 8 Auriga;. 



A Programme of Solar Research. — Now that the Mount 

 Wilson Solar Observatory has fairly settled down to work, 

 Prof. Hale has revised his " Programme of Solar Re- 

 search," published several years ago, and gives an outline 

 of the revised programme in No. 1, vol. xxiii., of the 

 Astrophysical Journal. 



Two principal studies are to be prosecuted. First, a 

 study of the sun as a typical star, with reference to stellar 

 evolution ; secondly, the relationship between solar and 

 terrestrial phenomena. 



These studies are divided into five groups, each of which 

 contains a number of subdivisions. The five main groups 

 are : — (1) direct photography ; (2) spectroheliograph re- 

 searches ; (3) spectroscopic investigations ; (4) studies of 

 the total solar radiation ; and (5) allied laboratory investi- 

 gations. 



Most of these are now being prosecuted at Mount Wilson, 

 and Prof. Hale points out that there are many other solar 

 investigations which call for attention, and of which many 

 may be carried out by amateur observers with modest 

 equipments. 



Harvard College Observatory. — Prof. Pickering's re- 

 port of the work done at Harvard College Observatory 

 during the year ending September 30, 1905, is the sixtieth 

 of the series, and contains the record of an immense amount 

 ol wink, too much even to summarise here. 



One or two special features may, however, be mentioned. 

 Eighteen eclipses of Jupiter's satellites and eight occup- 

 ations of stars by the moon were observed with tin- n-inch 

 Draper telescope. Three of the occultations were photo- 



