July 2 2, 1875 



NATURE 



233 



interesting note are really due to the proper motion of 

 the principal component of this triple star. 



Lalande 23726 (CORVUS).— With reference to the 

 query as to actual brightness of this star, which has 

 been noted as high as a fifth magnitude by Heis 'Naturp;, 

 vol. xii. p. 27), Mr. J. E. Gore writes from Umballa, under 

 date June 8 : — " I last night examined its place and found 

 the star in question to be barely visible in an opera glass 

 or about mag. 8." It is evidently variable to a consider- 

 able extent, and should be closely watched. Mr. Gore 

 adds that " L. 23675-76 rated 7, 'j\ by Lalande, is now 

 about 6m., and brighter than the stars L. 23463 (6m.) and 

 23446 (6m.), a little to the west ; " the observations in the 

 Hjstoire Celeste, however, do not belong to the same 

 object, but to the two components of a double-star, which 

 is 2 1669, and in the Dorpat scale were both estimated 

 6*5 in Menstircp Micr., and 6'o in Positiones Media; their 

 distance about 5^". Bessel also observed both com- 

 ponents, judgmg'them of equal brightness and of the 

 seventh magnitude in his scale. The appearance of the 

 object to the naked eye as a bright sixth, remarked by 

 Mr. Gore, is thus accounted for. 



Horizontal Refraction on VENUS.—In May 1849' 

 near the inferior conjunction of Venus with the sun, 

 Clausen having remarked that the crescent extended 

 beyond a semicircle, Miidler observed it with the Dorpat 

 telescope, with the view of approximating to the amount 

 of horizontal refraction in the planet's atmosphere. 

 Measures, properly so called, he found were hardly 

 feasible, owing to the extreme faintness of the cusps and 

 proximity of the planet to the sun, but estimations with a 

 position-wire in the field of view were made on six days 

 at distances varying from 3° 26' to 7° 37' ; fthe mean 

 gave for the horizontal refraction, 43'7. In 1866 Prof. 

 C. S. Lyman, by similar observations, obtained 45'*3 ; he 

 remarked : '* The planet was then (for the first time, as it 

 appears) seen as a very delicate luminous ring. The 

 cusps of the crescent, as the planet approached the sun, 

 had extended beyond a semicircle, until they at length 

 coalesced and formed a perfect ring of light." Last 

 December Prof. Lyman repeated these observations, 

 making use of a five-feet Clarke telescope of 4fj inches 

 aperture, and by measures of the extent of the crescent on 

 four days, deduces for the horizontal refraction of the 

 atmosphere of Venus, 44'*S, a value which is also the 

 mean of the three sets of observations. {American Journal 

 of Science and Arts, January 1875). At the next inferior 

 conjunction of Venus, she will have the following angular 

 distances from the sun's centre, at Greenwich noon : — 



The formula used for finding the horizontal refraction 

 may be thus written, putting C for the observed extent of 

 the crescent, d for the angular distance of Venus from the 

 sun at the time of observation, s for the sun's semi- 

 diameter, which we may express in minutes of arc, and r 

 for the planet's radius-vector : — 



Ilor. Refr. 



Arc ?in d sin i (C — 180°) 



The Sun's Parallax.— We have received Prof. 

 Galle's Bestinimung der Sonnen-Pai-allaxe aus cor- 

 Tcspondirenden Beobachtnnt^en dcs Planeten Flora (Bres- 

 lau, 1875), which contains the full details of his reduction 

 of the observations taken in both hemispheres near the 

 opposition of the planet in 1873, when it approached the 

 earth within about 0.87 of our mean distance from the 

 sun. The fing.l result for the parallax 8".873, as already 

 stated in this column, corresponds to 23,247 equatorial 

 semi-diameters of the earth, or, according to Galle, 

 19,979,000 geographical miles of 15 to the degree of 

 the equator. 



SCIENCE JN SI AM. 



"\^HEN the invitation of the King of Siam to observe 

 * * the late total echpse of the sun reached the Royal 

 Society, it was hailed with delight by those who took an 

 interest in the expedition. A few Europeans professing 

 to know something about the country wrote letters to news- 

 papers discouraging astronomers from accepting the invi- 

 tation. Happily no notice was taken of these anonymous 

 letters, and the result was that the members of the expe- 

 dition were surprised, not only by the good reception they 

 met with everywhere in Siam, but also by the great interest 

 the Siamese themselves took in the eclipse and in science 

 generally. The late king was well known for his love of 

 astronomy, but many might suppose that this was a soU- 

 tary case, and that with the death of the king science would 

 be left unprotected in the country. A short account of our 

 experience will show that the interest the Siamese take in 

 science is rather on the increase than on the decrease. 



On our way to the observatory, which was erected at 

 Bangtelue, near Chulie Point, we had to stop twenty-four 

 hours in Bangkok until the steamer which was to take us 

 was ready. It happened that the evening of that day 

 the "Young Siamese Society" met in the house we 

 were staying at, and I was asked by the members to 

 give a lecture on spectrum analysis and its application 

 during solar eclipses. Mr. Alabaster, aided by the King's 

 private secretary and Prince Dewan, acted as interpreter. 

 The Siamese listened with the greatest interest, and by 

 the questions they asked after the lecture was over 

 showed that they fairly understood the subject. There 

 exists a Siamese translation of a book on chemistry, and 

 they had read up the subject in that book. H.R.H. Chowfa 

 Maha Mala, uncle of the King, is the chief astronomer 

 of the Siamese at the present time. He showed me 

 the way in which he had determined the time and dura- 

 tion of the eclipse at Bangkok. Taking the sun and 

 moon's apparent diameter from the Nautical Almanac, 

 he determined by means of the projection of their paths 

 and their apparent velocity the time of the different con- 

 tacts. The drawing was neatly executed and, I am told, 

 the time thus determined came very near the truth. 



On the day of the eclipse several telescopes, one of which 

 had been lent to the King by Dr. Jansson, were set up on 

 the lawn in the front of the palace. The local time was 

 determined by Mr. Alabaster and Capt. Bush, in order to 

 find the exact time of the different contacts. As totality 

 approached, the King made a speech to the members of 

 the Royal Family, who were all assembled, telling them 

 why solar eclipses were observed, and why large sums of 

 money were spent for that purpose. During totality, his 

 Majesty observed the corona and the protuberances 

 through a telescope, carefully noting down what he saw 

 and making a sketch of the protuberances. He had 

 ordered one of the princes to take photographs of the 

 corona. Two photographs were thus secured, which by 

 no means are inferior to those taken at the Observatory of 

 Bangtelue. The original negatives of these photographs 

 have been sent to England as a present from the King to 

 the Royal Society. 



At our camp the Siamese also showed a great interest 

 in the eclipse. The eagerness with which the ex-Regent 

 looked through his telescope contrasted in a characteristic 

 way with the quiet indifference with which his European 

 secretary went to sleep during totality. 



The King of Siam informed us that he did not profess 

 to be an astronomer, and I was therefore rather surprised 

 to hear altcrsvards that on his journey to Calcutta he had 

 taken regular sights with the sextant, and calculated him- 

 self the position of the steamer. 



But the taste of the Siamese for science is not merely 

 confined to astronomy. Wangna, the second king, is a 

 mineralogist. The country in which he lives gives him 

 ample opportunity to work ^t his favourite subject. He 



