The older, devised by Hooke in 1667, is provided with valves above and below, both opening upward, through which the water passes freely during descent, but which are closed by some device on hauling up. The newer or slip water-bottle type consists of a cylinder allowed to drop on to a base-plate when a sample is tro be collected.
The remainder of his life he spent at Canopus, and Tro y near Memphis, where he died at the age of ninety-five.
This page gives an overview of all articles in the 1911 Brittanica which are alphabetized under Tro to Tze.
