During Mr. Christie's office, the two new departments of the Astrographic Chart and Double-star observations have come into being. The following buildings have been erected under his administration: the great New Observatory in the south ground, the New Altazimuth, the New Library, nearly opposite to it, the Transit Pavilion, the porter's lodge, and the Magnetic Pavilion out in the Park. Whilst in the old buildings the Astrographic dome has been added, and the Upper and Lower Computing rooms have been rebuilt and enlarged. As to the instruments, the 28-inch refractor, the astrographic twin telescope, the new altazimuth, the 26-inch and 9-inch Thompson photographic refractors, and the 30-inch reflector are all additions during the present reign. Roughly speaking, therefore, we may say that three-fourths of the present Observatory has been added during the nineteen years of the present Astronomer Royal. One exceedingly important improvement should not be overlooked. Airy observed little himself whilst at Greenwich, and had an inadequate idea of the necessity for room in a dome and breadth in a shutter-opening. With the sole exception, perhaps, of the transit circle, every instrument set up by Airy was crammed into too small a dome or looked out through too narrow an opening. The increase of shutter-opening of the newer domes may be well seen by contrasting, say, the old altazimuth or the Sheepshanks dome with that of the astrographic. This reform has had much to do with the success of later work. CHAPTER V THE OBSERVATORY BUILDINGS Like a living organism, Greenwich Observatory bears the record of its life-history in its structure. It was not one of those favoured institutions that have sprung complete and fully equipped from the liberality of some great king or private millionaire. As we have seen, it was originally established on the most modest--not to say meagre--scale, and has been enlarged just as it has been absolutely necessary. To quote again from Professor Newcomb-- 'Whenever any part of it was found insufficient for its purpose, new rooms were built for the special object in view, and thus it has been growing from the beginning by a process as natural and simple as that of the growth of a tree. Even now the very value of its structure is less than that of several other public observatories, though it eclipses them all in the results of its work.'