Page:History of the Royal Astronomical Society (1923).djvu/252

 220 HISTORY OF THE [1880-1920 complete by computing places by Hansen's tables for mean mid- night of every day during the years 1847-61, after which time Hansen's tables were used in the Nautical Almanac. Knowing thus H B for every midnight, interpolation would give that quantity for the actual time of every observation, and thus the determination of the apparent error of Hansen's tables could be completed. The expense of these computations was met by a grant of 320 from the Government Grant Committee of the Royal Society, and the results were published as an appendix to volume 50 of the Monthly Notices (1890). There are, of course, various kinds of ephemerides which can never find a place in the Nautical Almanac, nor in any similar publication. For a number of years, Marth had occasionally published ephemerides of satellites or for physical observations of the moon and the major planets. In 1882 June he was engaged by the Council to prepare such ephemerides regularly every year for publication in the Monthly Notices. This arrangement ter- minated in 1891, when the Council expressed their regret that they did not see their way to continue it any longer, but hoped that Marth would communicate the data on which his ephemerides had been computed. This, however, he declared himself unable to do at the time, but announced his readiness to continue the ephemerides without remuneration ; and he did in fact supply continuations of most of them till his death in 1897. From 1898 till 1906 similar ephemerides were published by Mr. Crommelin. At the Paris Conference in 1911 it was resolved that ephemerides relative to the physical observations of the sun, moon, and planets should be calculated by the American Ephemeris, and this has been carried out from 1916. The computation of ephemerides is often the first step taken after the announcement of an astronomical discovery, and it is therefore natural in this place to allude to the arrangements made for the rapid distribution of news of discoveries. The first attempt at such in this country was made by the late Lord Crawford, from whose Observatory the " Dun Echt Circulars " were issued from 1879 to 1889. Similar circulars were sent out by our Society in 1880-82, about fifteen in all. When the " Centralstelle " for the despatch of astronomical telegrams was started at Kiel, it was suggested to let the Society act as an intermediate station for this country, but this was found to be impracticable and was never carried out. The central office at Kiel continued to have charge of this matter until the war put an end to its activity. In 1919 the International Astronomical Union established a central bureau for astronomical telegrams at the Brussels Observatory. While the observatories in the United Kingdom, as a rule,