Ebook The Dominion Astrophysical Observatory, Victoria, B. C

The order for the large disc for the 72-inch mirror and for an auxiliary ?at of 55 inches diameter for testing the 72-inch was given to the St. Cobain Glass Works of Paris by the Jno. A. Brashear Co. As soon as the contract was awarded. The 72-inch disc was cast and annealed by June 1914 and was fortunately shipped at once without waiting for the 55-inch disc. It left Antwerp only about a week before war was declared and it was only by this small margin that Canada now has a 72-inch telescope. Grinding and polishing were at once begun but the lack of the large ?at and other difficulties delayed the completion and it was not until April 1918, about a year and a half after the completion of the mounting, that the figuring was finally completed and the telescope ready for work. Nevertheless, for an undertaking of such magnitude the work was completed in record time, four and a half years after the awarding of the contracts.