March 31, 1881] 



NATURE 



517 



Mr. Thomas Edward, the Banff naturalist, has reprinted in 

 a separate form some useful and interesting papers on the Pro- 

 tection of Wild Birds. The pamphlet is to be had at the 

 ■Banffshire Journal Office. 



'The additions to the Zoological Society's Gardens during the 

 past week include an Egyptian Gazelle {Gazclla dorcas) from 

 'Egypt, presented by the Earl of March, F.Z.S. ; a Common 

 Genet {Genetta vulgaris]. South European, presented by the Rev. 

 F. P. Voules ; a Giant Toad {Bufo agua) from Brazil, presented 

 by Mr. Carl Hagenbeck ; a Long-snouted Snake (Passerita 

 tiiyiterizans) from India, presented by Mr. H. H. Black ; an 

 Amherst's Pheasant (Thauinalea amhersticr) from Szechueui 

 China, a Black Swan (Cygnus alralus) from Australia, pur- 

 chased ; a Tiger (Felis tigris), a Bactrian Camel (Camelus 

 iactrianus), a Sambur Deer {Cervus arislotelis), born in the 

 Gardens. 



OUR ASTRONOMICAL COLUMN 



A TSTew Variable Star. — On July 26, 27, and 29, 1783, 

 D'Agelet observed a star which he twice estimated 6m., and on 

 the last night 6'5m. ; it is No. 5057-9 in Gould's reduced cata- 

 logue, the mean of the three obiervations giving for iSoo, R.A. 

 iQh. 23m. 47'S7s. and Decl. -\- I7":9'42"'8. The only sub- 

 sequent observation we have yet found of this star is in the 

 Durchtnusterung, where it is rated as low as 9 '4111. ; there is 

 consequently a high probability that it will prove to be a 

 remarkable variable. The position brought up to the beginning 

 of 1880 will be K.A. I9h. 27m. 22'is., Decl. + 17° 29' 28". 

 T)'Agelet's original observations will be found at pp. 542, 544, 

 and 546 of the Histoire Ctlcstc of I^alande. 



Minima of Algol, etc., in 1880. — Prof. Julius Schmidt 

 las published his observations, or rather the results of his obser- 

 vations, of Algol and other variable stars, made at Athens during 

 the past year. On comparing his epochs of minima with the 

 formula in Prof. Schonfeld's last catalogue, it will be found that 

 according to the most completely determined minima the calcu- 

 lation is too late by nearly half an hour. But the differences 

 between calculation and observ.ation are very irregular, so that 

 if we take a mean of the whole, the true minimum would appear 

 ito be earlier than thiit computed by only nineteen minutes. 

 The minima between August 28 and December 21 are here 

 compared. 



According to the observations of the same indefatigable 

 astronomer Mira Celt was at a maximum between July 20 and 

 25, but in 1880 it only attained about 4"2 m. A maximu.m of 

 R Leporis occurred about November 9 ; the determination is 

 ,not very certain. The intervals between maximum and 

 minimum, and vice versH of a Herculis were as irregular as 

 usual. 



The Red Spot upon Jupiter's Disk. — Dr. Jedrzejewicz 

 has published some inferences from observations for ascertaining 

 the time of rotation of the eastern extremity of the large red .spot 

 upon the disk of Jupiter, made at his private observatory at 

 Plonsk during the winter of l88o-8i. The instrument employed 

 is a refractor six-inches aperture, with powers 225 to 300. In 

 December he measured the length of the spot 9"*8, and considers 

 "that his own observations comjjared with those of Prof. Schmidt 

 ^t Athens, indicate that the length of the spit remained un- 

 changed during the winter. On this assumption he finds for the 

 time of rotaiion gh. 55m. 34-4I4S. ± 0'13s, by 174 rotations 

 between November 25, 1880, and February 5, 1S81. Prof. 

 Schmidt from 1021 rotations between July 23, 1879, and Sep- 

 tember 17, 1880, obtained the value gh. 55m. 34'422>. ± o'o5s. 

 -for the middle of the spot. In 1862, by observations upon a 

 spot which he says was much darker and a more favourable 

 object for the pur[)ose than the spots observed by Airy and 

 Miidler in 1834-35, and which was not much larger than the 

 shadow of the third satellite he had found for the time of rotation 

 gh. 55™- 25'684S. agreeing w ith the previously-determined values. 

 While the period from observations of the red spot is gs. greater. 

 Prof. Schmidt remarks that it agrees very nearly with that already 

 obiained by Mr. Pratt. 



The Minor Planets.— It appears that the object detected 

 by Herr Palija at the new Observatory of Vienna on the 23rd of 



last month, and which was announced as No. 220 of the small- 

 planet group, may prove to be No. 139 jfuewa, which had not 

 been observed since 1874. It was discovered by the late Prof. 

 Watson at Pekin on October 10 in that year, while he was enga^jed 

 upon one of the United .States expeditions for the observatinn of 

 the transit of \'enus, and as was reported at the time, without the 

 aid of a chart of telescopic stars, but from his memory of their 

 configuration about the particular spot occupied by the planet. 

 It was observed on November 8 by Riimker at Hamburg, but the 

 length of observation was not sufficient to determine the mean 

 motion with any degree of accuracy : hence although the ele- 

 ments had lieen several times brought up to more recent dates by 

 Watson, the |ilanet had not been recovered up to last month. 



By the last Berlin circular it would seem that hmcne will fall 

 little short of Hilda in the length of its revolution, and these 

 two minors will thus stand out as exceptional members of the 

 group. By the latest elements the period of Hilda is 2860 days 

 or7'832 years, and that of Ismene 2854 days or 7'8l4 years. 



Calculation has assigned the shortest period to No. 149 

 Medusa, liut this awaits confirmation, perhaps in the next sum- 

 mer, when the I'lanet should again come into opposition accord- 

 ing to the imperfect elements at present available. 



PHYSICAL NOTES 



M. Plantamour continues to study with his sensitive levels 

 the phenomena of periodic rise and fall of the ground which he 

 has observed in Switzerland. He believes he has established a 

 connection between these periods and those of the changes of 

 temperature of the earth's surface, there being an annual change 

 of level in an east-west direction corresponding with the mean 

 temperatures of the surface during the year. 



M. RosENSTlEHL concludes from his researches on the sensa- 

 tions of colour recently noticed that the three fundamental colour 

 sensations of the Young- Helmholtz-Maxvvell theory correspond 

 to the following tints of the pare spectrnm. Orange-red, three- 

 fourths of the distance from C to D amongst the Frauiihofer 

 lines, 3. yellow- g>-ecn three-quarters of the distance from D to E, 

 and a blue situated at one-third from F towards G. The prin- 

 ciple upon which this selection is made is that the selected tint 

 fulfils the following conditions : (a) it is equidistant between two 

 tints which are complementary to one another ; (h\ it produces 

 with either of the other selected tints another colour having a 

 minimum of white admixed with it. Thus the yellow-green 

 chosen is midway between that yellow and that blue which 

 produce the best white with one another, and it gives with the 

 selected orange-red a yellow more intense than any known yellow 

 pigment under equal illumination, and with the selected blue 

 gives a green moie intense than the richest green pigment. 



M. Henri Becijuerel observes that the specific magnetism 

 of ozone exceeds that of oxygen, and is much greater than could 

 be accounted for by the difference in density of these two alio- 

 tropic forms of the gas. 



'In vieiv of recent terrible colliery explosions in Belgium, M. 

 Comet has called attention (in the Belgian Academy) to a possible 

 interference of winds, blowing in an inclined direction, with the 

 proper ventilation of mines. Most of the "fiery" Belgian 

 mines have two shafts, one for raising the coal and for descent 

 of air, which, passing along the galleries, is drawn up the other 

 shaft by a ventilating engine. The orifice of the latter shaft is 

 generally (unlike that of the other) unsheltered by buildings ; it 

 debouches directly in the air a little above the ground. Obviou-ly, 

 then, a strong wind, blowing with downward inclination towards 

 this orifice, might seriously affect the ventilating action. It is 

 noted th.at one explosion in Hainaut on November 19, 1880, 

 folUnvei a night of ve.y high wind, which M. Cornet shows to 

 have been capable of depressing ventilation considerably. Mines 

 with large sections are more dangerous than others in atmospheric 

 perturbations. The true remedy, however (in the author's 

 opinion), is not increasing the resistance to the air-currents, but 

 sheltering the orifices of the ventilating shafts against descending 

 winds. 



In a recent pajier on the optical structure of ice (to the 

 Freiburg Society of Naturalists) Prof. Klocke finds that while in 

 the ice individuals the plane of the secondary axes is fixed by the 

 position of the principal axis, they are subject to 00 law as to 

 direction in that plane. 



The phenomenon of verglas occurred afUrbinoin Italy twice 

 in January ; and from his observations of it Prof. Serpieri con- 



