484 



NATURE 



{^Marck 27, 1879 



Unscientific Art (?) 



In Nature, vol. xix. p. 460, Mr, Buck complains of the 

 drawing in the GraJ'/ik for December 28, wherein the observer 

 is represented as "sloping the barometer at an angle of about 

 30° from the vertical," in order to take a reading on a marine 

 barometer by means of the lantern for better illumination. May 

 not the artist be correct, and Mr. Buck have discovered a mare's 

 nest? The barometer may be placed entirely horizontal for 

 reading the scale, after the vernier has once been set when the 

 instrument was vertical. 



Chas. Coppock 



Grosvenor Road, Highbury New Park, N., March 21 



OUR ASTRONOMICAL COLUMN 



The Distant Herschelian Companion of y Leonis. 

 — In 1861 Prof. Winnecke, writing from Pulkowa, drew 

 attention to a star of the ninth magnitude near the double- 

 star y Leonis, which M. Otto Struve had found to have 

 an annual proper motion exceeding o""5. The star was 

 observed with the Dorpat transit-instrument, on April 12, 

 1820, and once by Bessel in zone 502, on April 12, 1831, 

 and from these observations compared with two at 

 Pulkowa in April, 1861, and with micrometrical measures 

 from y Leonis by M. Otto Struve, Prof. Winnecke con- 

 cluded that the proper motion of the small star with 

 respect to the neighbouring binary, was very nearly o"-85 

 in R. A. and o"-io in declination, annually. Sir W. Herschel 

 observed a distant companion of y Leonis, the mean of 

 two angles giving 297°-5 for abotit i/Sa'g, with a distance 

 of iii""4, which he thought was "pretty accurate," though 

 as we are now aware, many of these wider measures of 

 Sir W. Herschel require material correction. 



We refer to this star from having remarked that M. 

 Flammarion, in his recently published " Etoiles Doubles 

 et Multiples en Mouvement relatif certain," has made it 

 the subject of a strangely confused article, which is calcu- 

 lated to mislead the reader who cannot refer to original 

 authorities. The star had been measured by Secchi in 

 1856, and by Powell in 1861, and M. Flammarion states 

 that " the enormous difference between the measure of 

 1782 and that of 1856" had induced him to search for 

 other observations and to reobserve it himself, which he 

 did, in 1877. He says he had found five observations by 

 Fiamsteed in 1691, ten by T. Mayer in 1755, and fifteen 

 by C. Mayer in 1777 ; these, it is added, are not very 

 precise, for they consist only of differences of right ascen- 

 sion, without taking account of the decHnation ; never- 

 theless he considered they had their value, and comparing 

 his own measures of 1877 with previous observations 

 separately, he deduces "a very surprising result," viz., 

 that the distant star is remarkable for its motion, which, 

 if one may judge by the totality of observations, has a 

 mean value of i"-o8, but which appears variable, as "at 

 present it certainly has not that value." 



The main cause of M. Flammarion' s difficulty is his 

 having confounded two quite distinct objects : we have 

 not referred to the work of C. Mayer, but the star ob- 

 served by Fiamsteed, which he more than once calls 

 "Comes y," and that observed by Tobias Mayer, is 

 really the bright neighbour of y, or 40 Leonis ; Flam- 

 steed did observe the declination, as will be seen in his 

 column " Distantice a vertice correctae ; " and Mayer 

 also noted the declination on one occasion, though gene- 

 rally recording only the right ascension. M. Flammarion 

 says he found five observations of Fiamsteed in 1691, 

 which is a greater number than we recognise in the 

 " Historia Coelestis," but there are observations in 1690 

 and 1692. The zenith distances of y Leonis and Comes 

 on April 6, 1691, and the names of the stars on January 

 23, 1692, are interchanged in the "Historia Coelestis." 

 Tobias Mayer's observations do not apply to the year 

 1755? when his observatory at Gottingen was not yet 

 erected, but to 1756 and 1757, chiefly the former year. 



Bessel's observation applies to 1831, not 1825, as M. 

 Flammarion assumes. 



The star in question is No. 90, in Argelander's valuable 

 treatise, " Untersuchungen iiber die Eigenbewegungen 

 von 250 Sternen, &c.," where he deduces for the annual 

 proper motion in arc of great circle, o"-5i2 in the direc- 

 tion 270'', or the proper motion is entirely in R.A. He 

 observed the star upon the meridian at Bonn, once in 

 1857 and four times in 1862-63. It was also meridionally 

 observed at Greenwich in 1862. It is No. 234, Hour X., 

 in Weisse's Bessel. Thus we have three stars situate 

 within half a degree, with large proper motions, very 

 divergent, however, in direction : — 



Secular P.M. Direction. 



Authority. 



40 Leonis 32-2 ... 229*0 ... Miidler. 



\V. B. X. 234 51-2 ... 270-0 ... Argelander. 



7 Leonis 32*3 ... ii8*6 ... Madler. 



A Meteor with Short Period of Revolution. — 

 In the very interesting report of the " Luminous Meteor 

 Committee" of the British Association for 1877-78, we 

 find a note by Capt. G. L. Tupman, referring to a fire- 

 ball seen on November 27, 1877, which he considers to 

 have been moving in a nearly circular orbit, with short 

 periodic time. Capt. Tupman observed this meteor from 

 a position about half a mile east of the Royal Observatory, 

 Greenwich ; it began as a first or second magnitude star, 

 but suddenly increased in brilliancy and size to a fine 

 bluish white fire-ball ten or twelve minutes in diameter, 

 emitting a train, coloured blue, red, and green, many 

 degrees long. It moved very slowly, so slowly, indeed, 

 towards the end of its course, that it appeared to come 

 almost to a standstill. The duration was considered to 

 be fifteen or sixteen seconds. The meteor was observed 

 by Mr. H. Corder, at Writtle, near Chelmsford, and by 

 Mrs. Ware, at Clifton Down, Bristol, and the positions 

 for beginning and ending, estimated at these stations, 

 were found to be in remarkable agreement, the true path 

 deduced from these satisfying them all, both azimuths 

 and altitudes, within 1°. 



It appears that the meteor first became visible at a real 

 height of fifty-six miles vertically over a point off the 

 mouth of the Thames in long. 1° 21' E., lat. 51^ 33', and 

 disappeared when it had descended to a height of thirteen 

 miles vertically over a point, about twelve miles west of 

 St. Omer, in France, in long. 2° o' E., lat. 50° 45', the 

 length of the entire path being about eighty miles. 



Capt. Tupman thinks the radiant point was pretty 

 accurately determined in R.A. 285°, Deck -+- 64'', or in 

 longitude 340°, and latitude -j- 83°. The elements of the 

 real orbit, which, with the aid of the other corresponding 

 data depending upon the earth's position in her orbit, are 

 thence deduced, are as follows, taking the real duration 

 at fifteen seconds : — 



Perihelion distance o'gSsS j Excentricity ... 0"I568 



Longitude of perihehon ... 70° 6' j Inclination ... 15° o' 



,, ,, ascending node 245° 50' I Anomaly ...-4° 16' 



Semi-axis major I"i69i ! Periodic time... 462 days 



Motion — direct. 

 The precise Greenwich time of the occurrence of the 

 meteor was loh, 26m. 



If the duration of visibility is diminished to 7 V seconds 

 the elements are still very similar to the above ; the semi- 

 axis major becomes r3785 and the period 591 days. 

 Capt. Tupman remarking that such favourable conditions 

 for inferring the orbit of a meteor may rarely happen, 

 adds, it is sufficient for the estabhshment of a short 

 periodic time (such as 500 days) that " the meteor moved 

 slowly from a fairly well- determined radiant distant about 

 90° from the point of the heavens towards which the 

 earth's motion was directed." 



We may mention that there is one singular circum- 

 stance not alluded to in Capt. Tupman's note : the 

 elements defining the position of the orbit of the meteor 



