322 



Anniversary Meeting. 



[Nov. 30, 



that obtained by Mr. Downing, in 1879, from the meridian observa- 

 tions of Mars at Leiden and Melbourne, as well as with the Yalues 

 fonnd from similar observations in 1862. In this investigation, Pro- 

 fessor Eastman rejects the observations at Cambridge, United States, 

 as they were made in a slightly different manner, and gives (in combi- 

 nation with Melbourne) a very large value for the solar parallax, viz., 



r-138. 



The detailed account of the British Observations of the Transit of 

 Venus, 1874, was published at the beginning of the year, and the 

 observations of the transit made at colonial observatories have been 

 recently printed in the Memoirs of the Royal Astronomical Society. 



The Transit of Mercury last November was well observed in 

 Australia and other places, and the results are of special interest in 

 connexion with the coming Transit of Venus. The discordances in 

 the times of internal contact recorded by different observers seem to 

 show that such observations are subject to much uncertainty. 



An important memoir on astronomical refraction has been lately 

 published by M. R-adau, who, after a discussion and comparison of 

 previous theories, gives formulas and tables for refraction, in which 

 allowance may be made for difference in the rate of decrease of tem- 

 perature with the height above the earth's surface at different seasons 

 of the year. M. Radau also discusses the case in which the surfaces 

 of equal temperature in the atmosphere are inclined to the earth's 

 surface. 



A new map of the solar spectrum, containing a much larger number 

 of lines than are shown in Angstrom's classical normal spectrum, has 

 been published by Professor Vogel in the publications of the new 

 Astrophysical Observatory at Potsdam. In this work Professor 

 Vogel has bestowed great care on estimates of the breadth and inten- 

 sity of each line. In the same volumes are given the results of Pro- 

 fessor Sporer' s sun-spot observations at Auelam from 1871 to 1879, in 

 continuation of those for the years 1861 to 1870, previously published. 

 From a comparison of the rotation-angles for 78 spots with the 

 formula, Professor Sporer finds that the larger deviations are always 

 towards the west, indicating that a descending current has brought 

 down with it the larger velocity of the higher regions of the sun's 

 atmosphere. The law previously deduced by Professor Sporer, that, 

 about the time of minimum, spots commence to break out in high 

 latitudes, and that the zone of disturbance gradually approaches the 

 equator till at the next minimum it coincides with it and dies away, 

 to be replaced by a new zone in high latitudes, is confirmed by the 

 recently published Auclam results, comprising (with Carrington's 

 series) two complete spot-cycles. 



In astronomical photography an important advance has been made 

 by the successful application of the new processes to the neb alas as 



