+--------------------+------------------+-----------+-------------+ | | Diameter of | Size of | | | | driving wheels. | cylinder. | Position of | | | ft. in. | in. in. | cylinder. | +--------------------+------------------+-----------+-------------+ |Great Eastern | 7 0 | 18 x 24 | inside | +--------------------+------------------+-----------+-------------+ |South-Eastern | 7 0 | 19 x 26 | " | +--------------------+------------------+-----------+-------------+ |Glasgow and | | | | |Southwestern | 6 1 | 18 x 26 | " | +--------------------+------------------+-----------+-------------+ |Midland, 1884 | 7 0 | 19 x 26 | " | +--------------------+------------------+-----------+-------------+ |North-Eastern | 7 0 | 171/2 x 24 | " | +--------------------+------------------+-----------+-------------+ |London and | | | | |North-Western | 6 6 | 17 x 24 | " | +--------------------+------------------+-----------+-------------+ |Lancashire and | | | | |Yorkshire | 6 0 | 171/2 x 26 | " | +--------------------+------------------+-----------+-------------+ |North British | 6 4 | 17 x 24 | " | +--------------------+------------------+-----------+-------------+ |Nord | 7 0 | 17 x 24 | " | +--------------------+------------------+-----------+-------------+ |Paris-Orleans, 1884 | 6 8 | 17 x 231/2 | outside. | +--------------------+------------------+-----------+-------------+ |Ouest | 6 0 | 171/4 x 251/2| " | +-----------------------------------------------------------------+ This table, the examination of which will be found very instructive, shows that there are already in use: For locomotives with single drivers, diameters of 9 ft., 8 ft. 1 in., and 8 ft.; (2) for locomotives with four coupled wheels, diameters 6 ft. to 7 ft. There is therefore an important difference between the diameters of the coupled wheels of 7 ft. and those of 8 ft. 3 in., as conceived by M. Estrade. However, the transition is not illogically sudden, and if the conception is a bold one, "it cannot," says M. Nansouty, "on the other hand, be qualified as rash."