200 



KNOWLEDGE. 



[September 1, 1899. 



the snow drifted in much faster than it could be dug out, 

 and it had to be left to drift up. All observations were 

 stopped for some hours until it had again become calm. 

 Then two or three hours' spade drill would clear the 

 passage through the snow. " This," writes Mr. Omond, 

 " was good exercise, no doubt, but a kind of work not 

 usually included in the routine of an observatory." When 

 the snow reached its winter depth of ten or twelve feet, 

 the work became stupendous, and even as late as May, 

 1884, the continuity of outside observations was broken 

 from this cause. By next winter the building had been 

 added to and improved, by having an oflSce and a tower 

 erected. The result was the lessening of the labour of 

 observations. There is now a door at the top of the tower 

 by which exit can be made at any time during the whole 

 winter. 



Since then — that is, for nearly sixteen years — hourly 

 observations have been taken without a break, except on 

 one or two occasions, when, for a few hours, wind and snow- 

 drift rendered it impossible to stand or see the thermometers 

 outside. Any ordinary gale can be faced if the observer is 

 protected by oilskins and keeps his lantern to leeward, but 

 sometimes the wind rises above one hundred miles an hour, 

 carrying with it drift and solid pieces of ice ripped off the 

 snow surface, which are sufficient to break the plate glass 

 windows of the Observatory if the latter do not happen 

 to be buried beneath the snow. I do not wish you to 

 imagine that you always have gales of this description 

 blowing ; it is an occurrence, perhaps, once or twice a 

 year, although gales of not so violent a character are not 

 infrequent. But now there is no need to break the 

 continuity of temperature observations, since a special 

 louvred screen has been devised to be read from within 

 the Observatory tower. And this, even when the wind is 

 blowing with great force, is very fairly correct. 



" The whole building is of a most substantial character. 

 It is aU on one story, except the tower, and consists of 

 double wooden walls covered with felt and surrounded 

 by dry stone walls, varying in thickness from four feet, in 

 the less exposed parts, to ten feet at the base of the tower ; 

 the windows are all double and the roof is covered with 

 lead overlaid with snow boarding. The strength of the 

 whole has been frequently tested by gales of a severity 

 and duration never experienced at lower levels." 

 (To be continued.) 



SOME SUSPECTED VARIABLE STARS.-II. 

 By J. E. Gore, f.r.a.s. 



I ANDROMED.E.— This star was rated a bright 4th 

 magnitude by Sufi, 4 and 5 by Lalande, 6 by Harding, 4 by 

 Argelander and Heis, 7 by Piazzi, and 3-4 and 7 by 

 d'Agelet. It was measured 4'56 at Oxford and 4-30 at 

 Harvard. My own observations, 187-5-1884, show well- 

 marked lluctuations in its light to the extent of about half 

 a magnitude. It is sometimes distinctly brighter than its 

 neighbour k Andromedte, and sometimes quite as distinctly 

 fainter. The observations, however, do not seem to show 

 any regular period. 



£ Pegasi. — This star, which is usually rated about 2| 

 magnitude, was found by Schmidt unusually faint in a 

 perfectly clear sky on November 5th, 1847. Signs of 

 variation were also found at Cordoba. Seidel from photo- 

 metric determinations believed it to be variable, and 

 Schwab's observations indicate a variation with a period 

 of about twenty-six days. 



83 UrsfE Majoris. — This star, which lies near ? Ursas (in 

 the Plough) , was seen by Birmingham as bright as J Urste 



in August 1868. Birmingham says : " This star, which 

 is ordinarily of the Gth magnitude, I saw as large as 

 8 UrsiB, between 3 and 4 magnitudes, on August 6fch, 

 1868. It was smaller on the next night, and slowly 

 diminished to its usual magnitude." It was rated 6-5 by 

 Argelander, and 5-6 by Heis, and was measured 5-10 at 

 Oxford, and 4-83 at Harvard. On January 28th, 1878, I 

 found it brighter than Alcor (the naked eye companion 

 to ?), but on February 7th, 1884, it was distinctly fainter 

 than the same star. 



c Virginis. — This star, which lies about two degrees 

 south of Spica (a Virginis), and is usually about the Gth 

 magnitude, was seen by Schmidt between the 4th and 

 5th magnitude on .lune 6th, 1866. It was then con- 

 siderably brighter than 68 (/) Virginis, which lies between 

 it and Spica. It gradually diminished in brightness, but 

 even on June 19 th it was still visible to the naked eye in 

 moonlight. Schjellerup, in his translation of Al-Sufi's 

 " Description of the Heavens," identifies the star with one 

 marked 19 of Virgo, by Sufi, and thus described by the 

 Persian astronomer, " La 19 est la mcridionale du cote pos- 

 terieure du quadrilatere, apres al-simak (Spica) s'incliuant 

 vers le sud ; elle est des moindres de la cinquieme grandeur ; 

 Ptolemee la dit absolument de cinquieme, mais elle est 

 plus pres de la sixieme. . . . Avec al-simak et la 17me. 

 (76 Virginis) elle forme un triangle isoscele, cette etoUe 

 etant au aommet." From this description it is absolutely 

 certain that Sufi's star is identical with the one seen by 

 Schmidt. Observations at Cordoba, 1871-73, vary from 

 5*7 to 6-3 magnitude, and the star would seem to be cer- 

 tainly variable, although it has not yet been admitted into 

 the list of known variables. In 1879, Burnham discovered 

 that the star was a very close double, the components being 

 6'2 and 6'5, and separated by less than half a second of 

 arc. 



65 Ophiuchi. — This star is supposed to have disappeared, 

 as it was duly observed by Flamsteed on May 6th, 1891, 

 and the observation was regularly reduced by him. No 

 such star is now to be found in the sky. It was looked for 

 at Greenwich, but without success. There is no star in 

 Flamsteed's position in Argelander's southern zones, or in 

 the Washington zones, nor is it in Lalande's Catalogue or 

 Harding's Atlas. It has been suggested that Flamsteed 

 may possibly have observed a so-called " now" or " tem- 

 porary star." 



37 Leonis Minoris. — Smyth (in his " Celestial Cycle ") 

 says that Piazzi called this star "by its old name Prfecipua, 

 as the lucida, or principal star of Leo Minor, registered of 

 the 3rd magnitude by HeveUus and continued so by Bode. 

 Mr. Bailey, however, in his recent edition of Flamsteed 

 has rated it 5j in lustre under the following plea. " This 

 star," he says, "is marked as of the 3rd magnitude in 

 the British Catalogue, but in the original entries it is 

 designated three times as of the 6th, once of the 4th, 

 and once as 4|, but nowhere greater. I have taken the 

 mean of the whole." Schmidt adds, "I have never seen 

 it but as given above from Piazzi" (4th magnitude). 

 It was rated 5-4 by Argelander and Heis, and was 

 measured 4*87 at Oxford, 4-76 at Harvard, and 4-90 at 

 Potsdam.-' On April 29th, 1886, I estimated it two steps 

 less than 81 (/3). 



? Piscis Australis. — This star was rated 5th magnitude 

 by Ptolemy, 5-6 by Sufi, 6 by Ulugh Beigh, 6i by Lalande, 

 6 by LacaUle and Harding, 6-5 by Behrmann, and 5-6 by 

 Argelander and Heis. Gould found it 6-6, or 6 7 from 

 observations at Cordoba. It was measured 662 at Harvard. 



* The standard star, Polaris, is in the Oxford photometiT 2"05, 

 iu the Hai'Tard 2'15, and in the Potsdam photometry 2'3i. 



