In this cylinder the distribution cannot be modified, that is to say, the active length of the expansion slide-valve is invariable. The interval comprised between one of the edges of this valve and the internal edge of the corresponding inlet orifice is equal, then, to 28 mm. when the axes of the two valves coincide. Let us describe, from _o_ as a center, a circle having this length for a radius, and let us again project the intersections of the radius, _o k_, with the crank circle upon a parallel at M M'. The external overlap, being the same as in the small cylinder, say 25 millimeters, the circle, _o e_, already traced for the distribution in the small cylinder, will serve for the distribution in the large one. Let us join its intersection with the circle, _c_, and the center, _o_, and let us trace also the circle of the internal overlap and the radii, _o g_, and _o h_, and we shall have all the elements of the distribution. _Advantages of the Engine._--The engine that we have just described presents all the advantages possessed by horizontal motors and double cylinder vertical ones without their many inconveniences. It, in fact, takes up less space than the former, while it possesses more stability than the latter. Its operation is as regular as that of an engine having two cranks adjusted at right angles. The cranked shaft, a costly member of an engine, and one whose duration is always uncertain, despite the care that has been taken in making it, is here done away with. The kind of distribution adopted is well adapted to the great variations in expansion, and, notwithstanding the two superposed slide-valves in each cylinder, two eccentrics suffice to operate them. The regulator, thanks to the mechanism that connects it with the expansion plate, is freed from all exaggerated resistance, the eccentric rod alone supporting the entire stress. The regulator is consequently very sensitive, and is capable of giving a coefficient of regularity which is more than sufficient in most cases. The condenser, with its wide apertures, is capable of operating with great speed without shock. We may add to this that the engine is simple and compact; the number of parts is few, and all can be easily got at; the bearings are long, and the wear is consequently reduced; the dimensions of the steam ports are wide and permit of great velocities being reached without counter-pressures; the mode of lubrication has been well studied, and requires but little attention on the part of the engine man; and, finally, the cylinder jackets and the superheating of the steam after it has begun to expand make this an economical motor aside from all the advantages that we have enumerated.--_Publication Industrielle._ * * * * * IMPROVED GAS ENGINE.