Feb. 3, 1 88 7] 



NATURE 



329 



above-mentioned 136 are also found in the Western Himalayas, 

 but this last region has a numberof endemic species which give it 

 its special character. The poverty of the fauna of the Pamir 

 plateau is obviously the consequence of its valleys being at a 

 height of no less than 10,000 feet above the sealevel. The 

 presence of the following species in the region will be interest- 

 ing to 200-geographers : — Saxicola finschi, Cyaneculaleucocyana, 

 fhrbivocula ticglccla, Acanthopncitste nitida, Trochalopierum 

 lineatuin, Microcichla scmiUri, Cyanistes flavipcctus, Rhodo- 

 /•ecAys sang^uinca, and Nisa^lus /ascialiis. 



In the Zritschrifl fiir hiitrumcntciikuiidc for September 

 1886 there is a paper entitled " Ueber eine Methode zur 

 Messung kleiner Winkeldifterenzen," by Herr Hugo Langner, 

 of Breslau. It describes a method of measuring the angle 

 between two plane reflecting surfaces when it is nearly an aliquot 

 part of two right angles, by measuring the difference between the 

 required angle and the nearest aliquot part. It is known that 

 in looking into the angle formed l)y two such surfaces the image of 

 any small object lying between them will be seen repeated. If the 



angle be nearly - I say - — S V then when 5 is positive, there 



will be a certain portion of the space between the two reflecting 

 planes where both nth images can be seen, but if 8 be negative, 

 there will be a space where neither can be seen. If, again, for 

 a small object a scale be substituted, then when 8 is -f two 

 images will be seen, and a certain portion of the scale will be 

 seen in both images; while if 8 be - there will be a portion which 

 is in neither image, and this superfluous or defective portion will 

 be a measure of- 8. Herr Langner proposes to place in front of 

 the angle, and at a considerable distance from it, a scale bent to 

 a cylinder whose axis is the intersection of the reflecting planes. 

 Observing with a telescope looking into the angle, the position 

 where a division of one image of the scale falls on the other 

 image can be read, and, if the radius of the scale be known, the 

 angle subtended by the relative displacement of the images, and 

 thence the difference between the approximate and real values of 

 the angle between the reflecting surfaces found. Ilerr Langner 

 gives as an example the determination of the angle of a right angled 

 prism of glas-^, of which a single determination would seem not 

 to be liable to a greater error than 4" or 5". And he suggests 

 that the method might be applied advantageously to deter jiine 

 the movements of a magnet by determining from time to time 

 the changes of the angle between a mirror fixed to the needle, 

 and one which is absolutely fixed, and to measure small varia- 

 tions of an angle in other cases. 



The little marine laboratory connected with the Johns 

 Hopkins L'niversity is almost as old as the great laboratory at 



! Naples. A sketch of its history is presented in a recent report by 

 Dr. W. K. Brooks, Director of the Marine Laboratory, to the 

 I'resident of the Johns Hopkins University. In 187S a small 

 appropriation was made by the Trustees of the University to 

 enable a party of biologists to spend a few weeks at the sea- 

 shore in the study of marine zoology ; and the scientific results 

 of the season's work were printed in an illustrated volume, the 

 cost of publishing which was borne by some citizens of Balti- 



I more. The next year the appropriation was renewed, and in 

 1880 the Trustees voted that the laboratory should be continued 

 for three years more, providing 4500 dollars for outfit and an 

 annual sum of looo dollars for current expenses. The scheme 

 worked so well that at the end of three years the institution was 

 maintained. After an examination of all the available localities, 

 the town of Beaufort, N.C., about 400 miles south of Baltimore, 

 was selected as the site for the laboratory ; and a vacant house, 

 suitable for the accommodation of a small party, was found, and 

 rente 1 as a laboratory and lodgings. This house has been occu. 

 pied during five seasons, and much good work has been done in 



it. During the season of 1886 a party of seven students went, 

 under the direction of Ur. Brooks, to carry on zoological investi- 

 gation in the Bahama Islands. 



The additions to the Zoological Society's Gardens during the 

 past week include three Hooker's Sea Lions (0/aria hooieri 

 S S 9) from New Zealand, presented by the Government of 

 New Zealand ; a Blue Penguin (Eiidyplula minor) from New 

 Zealand, presented by Dr. Bernard Lawson ; a Domestic Sheep 

 {Ovis arics i, four-horned var.) from Cashmere, presented by 

 Major Roland Poole ; two Wood Hares (Lepiis sylvaticus) from 

 North America, presented by Mr. Walter Ingram, F.Z.S. ; a 

 Blotched Genet {Genetta tigritia) from South Africa, presented 

 by Capt. J. Robinson ; a Grey Ichneumon [Herpestes griseus) 

 from India, presented by Mr. .Stanlake Batson ; a Spotted-billed 

 Duck (Anas poccilorhyticha) from India, received in exchange ; 

 three Lions (FJis ho), an Axis Deer {Cervus axis i) born in 

 the Gardens. 



OUR ASTRONOMICAL COLUMN 



"^The New Algol-type Variable. — Mr. Chandler has 

 been able (Gould's Astronomical Journal, No. 150) to secure 

 some further observations of this star, which, so far as they go, 

 tend to confirm the hypothesis of a period of about three days. 

 Minima were observed on January 2 and 11, but these were 

 inconclusive as to the period. The star was, however, observed 

 on January 12, between I7h. I5h. and iSh. 5m., to beapparently 

 of its normal maximum brilliancy, whereas the first rough ele- 

 ments formed would have given a minimum at lyh. 50m., had 

 the period been I •4992d. or 07496d. Further observations are 

 much desired. It unfortunately happens, from the star's period 

 being very closely commensurable with the mean solar day, that 

 further observations of minima will be scarcely possible in 

 Northern Europe or Eastern North America for many months. 



Gore's Variable NEAR x' Orionis. — Dr. G. MUlkr, from a 

 series of observations extending from 1S86 November 9 to 

 1887 January 8, finds that the star attained its maximum on 

 1886 December 12. Assuming the light-curve the same at the 

 preceding nnximum, it will have been at its brightest on 1885 

 December 13, so that the period will be about 364 days. 



The Southern Comet. — The following telegram has been 

 received from Cape Town, from which it appears that the new 

 southern comet resembles that of 18S0 I. in its orbit as well as 

 in its physical appearance: — "Cape Town, January 26. — No 

 condensation observable ; riband of light 35" long, narrowing 

 towards sun, position narrowest part near as can observe, 

 Janu.ary 22-317 G.M.T., K.A. = 322° 31', N.P.D. = 135° 48'. 

 The orbit presents a close resemblance to Comet t88o I. Peri- 

 helion, January II, noon." The comet is rapidly diminishing 

 in brightness, and it is already invisible to the naked eye. 



A Short Method for Computing Refractions. — Inlhe 

 Aslronomischc Nachrichtcn, No. 2768, Mr. Schaeberle, of the 

 Ann Arbor Observatory, explains a short and convenient method 

 for computing astronomical refractions between 0° and 45° 

 zenith distance. Let k and k^ be respectively the true and 

 mean refractions when 2 = 45°, then for any other zenith 

 distance less than 45° the approximate true and mean refractions^ 

 would be given respectively by 



r — k tan z, ^j — l\ tan z, 



from which is derived 



/■„ - /■ 



'■='•«- ^- '■" 



an expression which, for the assigned limits of zenith distance, 



will give the true refraction wi'hin o"'oi, provided the true 



value of r^ is used in the second memb;r of the equation. The 



factor " ~ will, ho.vever, be constant only so long as the 



barometer and thermometer readmgs remain unchanged. To 

 allow for changes in these quantities, let F-^ and F^ denote 

 respectively the values of these factors at the times 7\ and T.^ V 



