ANNUAL ADDRESS TO THE MEMBERS 

 OF THE SOUTH AFRICAN PHILOSOPHICAL SOCIETY, 



On the 29th August, 1888, 



By the President W. H. Finlay, M.A., F.R.A.S. 



THE PROGRESS OF ASTRONOMY DURINa THE LAST TEN OR 



TWELVE YEARS. 



I propose to bring before you this evening a review of the Progress 

 of Astronomy during the last 10 or 12 years, a review at least of some 

 of the chief points in which our knowledge has been advanced, as 

 an account of all of them would be too long for this address. The 

 theory of Astronomy during this period has not attracted so much of 

 the attention of the younger generation at our Universities, their 

 attention having been diverted to the newer theory of Electricity 

 with its manifold developments ; there is however a goodly number of 

 advances in theoretical Astronomy to be recorded, but I cannot 

 venture on a detailed account of them to-night. 



A large amount of work has been done in connection with the 

 shape and dimensions of the earth. Bessel's value of the ellipticity, 

 or ratio of the difference of the axis of the earth's spheroid to the 

 major axis, was ^^q^. It was derived from arcs of the meridian 

 measured in France, Sweden, Russia, India and Peru. From ex- 

 tensions of these arcs and new ones, measured with more refined 

 instruments Col. Clarke has shown that Bessel's value is too small 

 and that -^\^ is nearer the truth. His result has been confirmed by 

 pendulum observatious in India by Col. Herschel, and by the U.S» 

 Coast Survey in America. But it has been made abundantly manifest 

 in these investigations that no one spheroid or ellipsoid will represent 

 the earth's shape with exactitude : and that just as there are 

 departures from uniformity on the earth's surface in the shape of 

 mountains, there are anomalies in astronomical latitudes and longitudes*. 

 Notable examples of these have been found in Russia and the island^ 



