F, are caused to approach the cylinder, D, both are raised at the same
instant.

When the cylinders, F, occupy the position represented in the engraving
by unbroken lines, the flat plate, O, is simply submitted to pressure
between the cylinders, D and P, the cylinders, F F, then merely acting
as guides. But when, while the plate is being thus flattened between the
principal cylinders, the accessory cylinders are caused to rise, the
plate is curved as shown by the dotted lines, O' O'. To obtain a
uniformity in the position of the two cylinders, F F, the following
mechanism is employed: Each cylinder has an axle, to which is affixed a
crank, Q, connected by means of a rod, R, with the slide, G. These axles
are also provided with toothed sectors, L L, which gear with two screws,
L L, whose threads run in opposite directions. These screws are mounted
on a shaft, N, which may be revolved by any suitable arrangement.

[Illustration: ROLLING MILL FOR MAKING CORRUGATED IRON]

* * * * *




RAILWAY TURN-TABLE IN THE TIME OF LOUIS XIV.


The small engraving which we reproduce herewith from _La Nature_ is
deposited at the Archives at Paris. It is catalogued in the documents
relating to Old Marly, 1714, under number 11,339, Vol. 1. The design
represents a diversion called the _Jeu de la Roulette_ which was