The Northern of France Company has a few engines of immense power. Passengers between Calais and Paris may have observed them occasionally at stations. Their funnels lay horizontally on the upper surface of the boilers until near their extremities, when they bend upwards; their mouths are thus perpendicular, like the funnels of ordinary engines. The weight of each of these locomotives is nearly forty-five tons, and it is said that they can easily draw loads of 600 tons; but their adoption is not likely to he general. They must be very injurious to the road and very destructive of couplings, &c. Not content with this weight, the Northern of France Company exhibited in the Paris Exhibition a four-cylinder twelve-wheel tank engine, made by Messrs. Gouin & Co., the weight of which, fully loaded with fuel and water, is 58½ tons. It has 1,920 feet of heating surface. In 1863, M. Thouvenot, a French engineer, proposed, in a pamphlet published at Lausanne, the construction of a colossal locomotive, the weight of which was to be 82 tons, horse power 582, heating surface 5,512 square feet, estimated consumption of fuel 250 lbs. per mile. This engine was proposed principally with the view to the ascent of mountains by railway; yet the weight of the train was to be less than the weight of the engine—only seventy-four tons. The speed estimated was twelve miles an hour. No such engine has as yet been, or is ever likely to be, constructed. The earliest passenger locomotive engines were all made with “inside cylinders,” that is engines, the cylinders of which were within the framework. The late Mr. Joseph Locke we believe first introduced “outside” cylinder engines, that is, cylinders outside the framework, and at once visible to the eye. The “Crampton” engines—a great favourite in various parts of the continent, especially on the Northern of France Railway, but never in England—all have outside cylinders. The outside cylinder engine was very popular some twenty years ago, but the tendency of engineers, especially since the introduction of steel-cranks, is to revert to inside cylinders. Even at the Crewe manufacturing shops, where formerly none but outside cylinder engines were built, engines with inside cylinders are now constructed. The same on the Great Eastern, and one or two other lines where outside cylinders were at one time exclusively adopted.