TRANSACTIONS OF THE SEJCTIONS. 25 



When it is required to return the mercury to the bulb for the purpose of making 

 a fresh observation, the end furthest from the bend is to be elevated, and the instru- 

 ment slightly agitated ; by this means the metal repasses the obstruction and indi- 

 cates the temperature at the time. 



Mr. Williams called the attention of the Section to the advantages of having the 

 scale engraved on the stem of the instrument, thus preventing the danger of error 

 from alteration of the scale, which may result from wooden ones being exposed to 

 damp, or too high a temperature. The instrument is also provided with another 

 glass scale more boldly graduated, attached to the tube, to facilitate reading off. 



Astronomy, Meteors, Waves. 



On the Establishment of a Magnetic Meteorological and Astronomical 



Observatory on the Mountain of Angusta Mullay, at 6200 feet, in Tra- 



vancore. By Astronomer Broun. (^Communicated by Colonel Sykes.) 



Astronomer Broun, in a letter to Colonel Sykes dated 2nd of July, 1855, describes 



the successful establishment of an observatory on Angusta Mullay, at 6200 feet 



above the sea-level, for the purpose of simultaneous record with the Observatory at 



Trevandrum. 



The diflSculties of access to the summit of the mountain were so great, from 

 having to cut paths through dense jungles infested by elephants and other wild 

 animals, from having to use ropes and mechanical aid in getting up the building 

 materials, provisions, and the instruments, and in the delays from the labourers 

 running away from fright and the effects of cold, that two years were consumed in 

 the undertaking. The object of Astronomer Broun, in making known his successful 

 efforts in Europe, is to enable observers to put themselves into communication with 

 him, in case they should desire to have any experimental researches made in so 

 novel a position for an observatory. 



On certain Anomalies presented by the Binary Star 70 Ophittchi. 

 By W. S. Jacob, Director of the Madras Observatory. 



This pair has been long known as a binary system, but the exact orbit is yet in 

 doubt, although nearly a whole revolution has been completed since it was first 

 observed in 1779. 



All the orbits that have been computed fail in representing the true positions at 

 certain points, and those which best represent the angles fail entirely as regards the 

 distances. 



The most remarkable point is, that even in those orbits which agree best with 

 observation, the errors in the angles assume a periodical form, retaining the same sign 

 through a considerable space. 



An orbit has been computed with a period of ninety-three years, in which the 

 errors are -|- from 1820 to 1823, — with one exception from 1823 to 1830, doubtful 

 -from 1830 to 1832, and from 1833 to 1842 all +, after which they continue for the 

 most part — . 



This must depend upon some law : it might arise from a change in the law of 

 gravitation, but may be accounted for more simply by supposing the existence of a 

 third opake bodj' perturbing the other two. Such bodies have been already sur- 

 mised to account for irregular motion of apparently single stars, such as Sirius and 

 Procyon. 



The body in this case, if supposed to circulate as a planet round the smaller star, 

 need not be very large, as the deviation from the ellipse does not exceed 0"'l of arc. 



Assuming the small star to describe a secondary ellipse, in which o=0"'08, 

 e=0'15, P=26 years, and ra=200°, and applying corresponding corrections to the 

 positions, the average error in the angles is reduced from 50' to 37', and in the 

 distances measured subsequent to 1837 from 0"-14 to 0"-] 1, or by about i. 



There is therefore prima facie evidence for the existence of such a body, and it is 

 desirable that the fact should be still further tested by careful observation. 



