Transportation of 100-inch mirror to Mount Wilson Observatory. The mirror is covered with a white tarpaulin and is loaded into the back of a truck. A small crowd of men and women surround the mirror on the truck. One of the Observatory's domes is seen behind some trees. The truck with the mirror is seen approaching the Observatory on a dirt road. Image courtesy of the Observatories of the Carnegie Institution for Science Collection at the Huntington Library, San Marino, California.