Page:History of the Royal Astronomical Society (1923).djvu/246

 214 HISTORY OF THE [1880-1920 tion of Kapteyn, who measured all the plates, the publication of three volumes of the Annals of the Cape Observatory was com- pleted in 1900, containing approximate places of 454,875 stars south of 18 Declination. A rare example of an immense piece of work carried out in a comparatively short time by the unwearied patience and perseverance of two individuals working at a great distance from each other. In the meantime the French Academic des Sciences had invited scientific bodies and observatories in all countries to send dele- gates to an international astrophotographic congress, to be held in Paris to discuss the preparation of a photographic chart of the heavens. The congress was opened at the Paris Observatory on 1887 April 16. Of the eight members from Great Britain, three (Common, Knobel, Tennant) represented our Society, and a full report of the proceedings was printed in the Annual Report of the Council in the following February.* The following are the prin- cipal resolutions of the congress : A chart to be made of all stars down to the fourteenth magni- tude, the plates to be in duplicate. A second series of photographs with shorter exposure, including stars to the eleventh magnitude, to be made concurrently in order to form a catalogue and to determine fundamental positions in the first series. The photographic telescope to be essentially similar to that used by MM. Henry. After receiving the report of the delegates the Council appointed a deputation to wait on the Prime Minister (Lord Salisbury) and urge the desirability of this country taking part in this important undertaking. The deputation was, however, not received, as it was believed that it would not " lead to any profitable result." Eventually Greenwich Observatory was provided with a photo- graphic refractor and enabled to undertake the zone +90 to +65, while De la Rue generously presented the Oxford University Observatory with a similar instrument, with which the zone +31 to +25 Declination has been observed. These two Observa- tories have long ago finished their share of the Carte du del, but several zones undertaken elsewhere are not yet completed. As the Society did nothing further, no more need be said. The rapid rise of the application of photography has caused a great demand for negatives for serious study, for lantern slides for lectures, and prints for more casual examination or wall-decora- tion. The Society appointed a permanent Photographic Committee as early as 1887 June ; it has been regularly renewed every year. To include in our publications any large number of reproductions
 * Monthly Notices, 48, 212.