Melbourne, Aug. 29. - A colusión oocurred yesterday in the Port of Philip Heads between the steamer üambier and Easby. The üambier was bound írom Sydney, Nev South Wales, for Melbourne, and was just clearing the heads when shc met the Easby bound out. It was irapossible for the vessels to clear each other, and the Easby struck the Gambier amidships, crushing her side to such an eXtent that when she backed away the water poured into the hold of the Gambier in torrents. Seven minutes after the collision the Gambier gave a long forward lurch, then her bows rose high out of the water, then she settled back, and, sinking stern first, she disappeared from view carrying with her five saloon passengers, fifteen steerage passengers and six of the crew.