DECEMBER 14, 18St} explored the Antarctic as far as 77° S., and might have gone RAILWAY BRIDGES.-THEIR MATERIAL AND MODE OF further perhaps but were stopped by the land of the Antarctic CONSTRUCTION. continent. The Southern hemisphere has a more even temperature owing to its greater amount of water, and the same Jervis in his "Railway Property" make.s the foHowing has been considered the reason why the thermal equator is very just remarks on the bridges of railways which are par north of the

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... l equator, excepting in the middle Pacific. ticularly pertinent in view of the disasters occurring in vari The greater amount of water south has probably coolOO the ous sections of the country from the insecurity of these struc· crust of the earth to a greater depth there than at the north, tures. His directions and suggestiol1s will be found to be and the internal heat of the earth has less influence on the valuable: surface there than here; at least the curving in the'thermal "In this country bridges are mostly constructed of wood; equator seems to indicate that its location is influenced by th" in England, brick is very extensively used, and in that mild amount of land. climate may answer a good purpose. So long as bricks con-