it 



March 15, 1900J 



NA TURE 



479 



of manganese he has obtained, which is of interest irom the 

 point of view of the valency of the metal. Fluorine gas reacts 

 readily with powdered manganese, and analyses of the resulting 

 product showed that a higher fluoride than MnFj was formed, 

 but owing to the violence of the reaction this fluoride was not of 

 constant composition. The interaction of fluorine and man- 

 ganous iodide, however, gave a definite fluoride, MnaF^, which 

 in many of its reactions behaves like free fluorine, pentachloride 

 of phosphorus giving PFj, and amorphous carbon a fluoride of 

 carbon. On heating it splits up into MnFa and fluorine gas. 



The additions to the Zoological Society's Gardens during the 

 past week include a Patas Monkey (Cenopithectis fatas, 9 ) from 

 Nigeria, presented by Mr. Cecil Masters ; a Macaque Monkey 

 (Macacus cynomolgus, <J ) from India, presented by Mrs. Herbert 

 Grifiith ; a Vulpine Phalanger [Trickosunis vulpecula) from 

 Australia, presented -by Mrs. Walter Crane ; a Persian Gazelle 

 ( Gazella subgtitturosa, <J ) from the Persian Gulf, presented by 

 .Mr. B. T. Ffinch ; an Alligator (Alligator mississippiensis) 

 from North America, presented by Mr. J. Turner Turner ; a 

 Ludio Monkey {Cercopithecus hidio) from West Africa, a Brown 

 Capuchin (Cebtts fatuellus) from Guiana, deposited ; four 

 Cockateels (Callopsittacus novae- hollandiae) from Australia, 

 purchased. 



OUR ASTRONOMICAL COLUMN. 



Search kor an Intramf.rcurial Planet. — Harvard 

 College Observatory Circular, No. 48, consists of a description 

 of a plan, prepared by Prof. W. H. Pickering, for observations 

 during the coming eclipse of the sun, with the object of making 

 a thoroughly systematic search for a possible planet revolving 

 between Mercury and the sun. It is not usual for the obser- 

 vatory to arrange expeditions for solar eclipses, except in the 

 case of the trial of a new problem, when grants of money and 

 instruments are made especially for such work. 



In explanation of his plan. Prof. Pickering starts with the 

 statement of the observed fact that "the faintness of a star that 

 may be photoeraphed with a given instrument against a bright 

 background of sky depends, within certain limits, directly on 

 the focal length of the lens, and is independent of its aperture." 

 It has also been previously pointed out [Harvard Observatory 

 Annals, xviii. p. 104) that " three minutes after the pole star 

 first becomes visible to the naked eye in the evening, the sky 

 surrounding it is of about the same photographic intensity as 

 that of the sky near the sun during a total solar eclipse." 



Using a photographic lens of 3 inches aperture and 11 feet 

 4 inches focal length, the field was large enough to cover nine 

 8x10 inch plates. With an exposure of one minute to the region 

 of the pole, about three minutes after the pole star became 

 visible, was sufficient to appreciably darken the plate, but not 

 enough to obscure the images of stars down to the eighth mag- 

 nitude. Four of these instiuments will be employed in May 

 next, all attached to the same mounting, and arranged so as 

 to photograph a region about 32° x 10°, having the sun as 

 centre. 



As the earth passes through the equatorial plane of the sun 

 only about one week after the eclipse, this will be a favourable 

 time for such a search, as the planet would appear somewhere 

 on the narrow line forming the projection of this plane upon 

 the celestial sphere. 



The Harvard Expedition for this purpose will be stationed in 

 the State of Alabama, but as even a successful observation at 

 only one station will be insufficient to compute the orbit or 

 determine its distance from the sun, it is therefore hoped 

 that some other observer will be able to duplicate the work in 

 Spain or Algeria. Alhough, of course, it would be desirable to 

 also employ four cameras, if possible, this is not necessary, and 

 two lenses, one photographing the region on each side of the 

 sun, would, in conjunction with the Harvard plates, be sufficient 

 to confirm the discovery and permit the compulation of an 

 approximate circular orbit, which could then be more 

 accurately determined at the next eclipse in 1901. 

 . The New Twin Refractor at Potsdam. — The great 

 refractor which has been installed at the Astrophysical Ob- 



NO. 1585, VOL. 61 J 



servatory at Potsdam was recently formally dedicated and 

 prepared for its assigned work. Director H. C. Vogel gave the 

 inaugural address, after which the instrument and its observatory 

 were explained by Prof. Scheiner. The telescope has two ob- 

 jectives, one of 80 cm (32 inches) aperture and 12 m. (39-4feet)' 

 focal length, and another of 50 cm. {20 inches) aperture and 

 12^ m. (41 '2 feet) focal length. Both objectives were made by 

 C. A. Steinheil and Sons, of Munich, the larger being corrected' 

 for photographic, the smaller for visual use. The mounting is by 

 Repsold and Sons, of Hamburg. The dome is 22 m. in- 

 diameter and 18 m. high, the hemispherical movable part 

 being of iron with an inner lining of wood ; this may be rotated 

 either by hand or by means of electric power. The observing 

 platform is rather unusual, being suspended from the dome, with 

 which it moves, directly opposite the observing slit. The 

 motion of this platlorm, and the opening or closing of the slit in^ 

 the dome, are controlled electrically from the eye end of the 

 telescope. The instrument is to be primarily devoted to the 

 determination of the velocity in the line of sight of 500 stars, 

 and the two spectrographs, built specially for the telescope by 

 Toepfer, have passed successfully the preliminary tests. An ex- 

 cellent reproduction of the instrument in position forms the 

 frontispiece of the Astrophysical Journal iot January 1900, from 

 which the above details have been abstracted. 



The Benjamin Althorp Gould Fund.— In the Astro- 

 nomical Journal, No. 477, Messrs. Lewis Boss, Seth C. 

 Chandler and Asaph Hall, Directors of the Fund, make the 

 following announcement -.—"Since making appropriations, in 

 March 1899, of 500 dollars to Prof. Charles L. Doolittle, and 

 of 300 dollars to Mr. Henry M. Parkhurst, from the Benjamin 

 Althorp Gould Fund, a considerable amount of income has 

 accrued, for the distribution of which the Directors are prepared 

 immediately to arrange. Applications for appropriations may 

 be made by letter to any of the aforesaid directors, stating the 

 amount desired, the nature of the proposed investigation, and 

 the manner in which the appropriation is to be expended. 

 Full information with regard to the Fund may be found in the 

 announcement pertaining thereto in A.J. 453, a copy of which 

 will be mailed, on request, to assist in framing applications." 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridce. — Mr. H. Woods, St. Ji)hn's College, has beere 

 appointed University Lecturer in Pakeozoology. 



The Medical School Buildings' Syndicate report in favour erf" 

 plans for the schools of pathology, pharmacology, public health 

 and medicine, prepared by Mr. E. S. Prior. The estimated 

 cost is about 35,000/. 



The degree of Doctor of Science is to be conferred on Mr. 

 Charles Hose, of Sarawak, whose contributi ms to the ethnology, 

 zoology and botany of Borneo have won for him a high 

 reputation. 



The honorary degree of Doctor of Laws has been conferred 

 upon Prof A. R. Forsyth, F.R S.,and Prof. A, S. Woodward, 

 by Glasgow University. 



Every student before graduating from the Massachusetts 

 Institute of Technology has to present a satisfactory thesis. 

 Time is allowed for this work in the second term of the fourth 

 year. The theses thus afford students an excellent opportunity 

 to perform original research work. In the course of electrical 

 engineering, a Japanese student has chosen for his subject a 

 study of the size of wire necessary when aluminium is used for 

 a conductor of electricity. He is to study the relative cajxicity 

 of aluminium as compared with that of copper. As the price erf 

 copper has risen so much, and as the price of aluminium has- 

 fallen, the use of the latter metal has already begun to compete 

 with that of copper in electrical manufacture. Insurance com- 

 panies have appointed a committee to follow the results of such 

 tests, and to make tables from them, as it is most important to 

 know, when buildings are wired, the safe limit of the amount of 

 current which any wire covered or uncovered may be made to 

 carry. In the method chosen for determining the relative 

 capacity of the aluminium, the temperature of the wire is 

 measured directly, while the wire is carrying different amounts 

 of electricity. 



