service to astronomical science as calculators. What a number of names we might cite of those who have given their time to the collection of observations and determining the courses which comets and the minor planets describe in space! The positions of three hundred thousand stars are now known; one third of the work of determining them has been done by volunteer astronomers. The famous catalogues of stars to which we have recourse in official observatories have been prepared in the private observatories of Wrottesley, Hartnup, and Groombridge. To produce such results, how great must have been the zeal and devotion of those amateurs who, after numerous years of watching, have been able to get together thousands of observations, with no reward except the personal satisfaction of having been serviceable to astronomy! Such labors, which are of the most ungrateful kind, and to which professional astronomers devote themselves, have no immediate result. The glory and fame which the discovery of a comet or a planet brings at once to its author are not to be found in them. They serve for the preparation of material which it is certain can not be productive for ages to come; for it is only then that these catalogues can help establish by comparison with new catalogues minute displacements of stars on the celestial vault, and can furnish the means of calculating the proper motions of these stars, and consequently of determining the direction and velocity of the movement of our solar system in space.
We need not go further in the enumeration of the various lines of progress and the discoveries that are due to private persons. We can appreciate to a certain degree the extent of the services rendered by them when we see the strongest astronomical society, that of London, distributing in fifty years more than a third of its annual medals to amateur astronomers.
Other laborers than astronomers have assisted in the advance of the science by furnishing amateurs easier means of examining the sky and bringing the greatest exactness into their observations. Among them are such men as Molyneux, Dent, Grubb, Alvan Clark, Secretan, and the clockmakers, machinists, and opticians who have placed their constructive talent at the service of astronomy. We should not forget to pay our tribute of admiration to the Dudleys, Licks, and Bishoffsheims, who have disinterestedly employed their large fortunes in constructing and furnishing observatories, and providing means to assure their existence in the future.
What emulation prevails among amateurs in astronomy! They pride themselves on cultivating the science as independent men, and spare neither time nor pains to secure a place in the legion which enrolls Copernicus and Herschel in its ranks. One can, indeed, engage with profit in those beautiful studies without
