“Independent of the energy, perseverance, and straightforward practical sense, of which he has given proof, in his long train of trials and experiments, Mr. Fell’s principal merit, in our opinion, is that he has understood, what theory entirely justifies, that locomotives with additional adhesion are only applicable to steep gradients and slow speed, because such engines are able to develop powerful means of traction, without heavy additions to their weight.” Early in 1863, Mr. Fell instituted experiments on a length of line of 800 yards, laid out on his plan, upon the Cromford and High Peak Railway, near Whaley-Bridge. The gauge was 3 feet 7½ inches, 180 yards of the line were straight with a gradient of 1 in 13 (406 feet in the mile); 150 yards with a gradient of 1 in 12 (440 feet in the mile); with curves of _two chains and a-half each_. The centre rail was raised seven and a-half inches above the surface of the two ordinary rails, so as to be acted upon by the two horizontal wheels of the engine. During the experiments, the first engine of the kind ever constructed, and necessarily, from want of experience, unsatisfactory in many of its details, working with a pressure of 120 lbs. to the square inch, was always able to convey a load of twenty-four tons up the incline. The maximum it succeeded in taking was thirty tons. Its dimensions were as follows: diameter of cylinder, 12 inches; length of stroke, 18 inches; four wheels coupled, diameter 2 feet 3 inches; axles, 5 feet 3 inches apart. The weight of the engine fully loaded with coke and water was sixteen tons. When the pressure was only brought to bear upon the vertical wheels, the engine could not take more than a weight of seven tons up the incline, but when the horizontal wheels acted combinedly with the perpendicular, she took up twenty-four tons on the same day, and under circumstances precisely similar in every respect, except as regards the action of the horizontal wheels upon the centre rail. These experiments were considered so satisfactory, that it was decided, with the permission of the French Government, and for its information, that they should be repeated upon a more extended scale upon the Mont Cenis, with the condition made by Mr. Fell, that if the system were found to be practicable, the authorities should grant the concession of a portion of the roadway for a line to be laid down across the French division of the mountain on the same terms as had already been agreed to by the Italian Government for the Italian portion.