complicated screw system.

ESTRADE'S HIGH SPEED LOCOMOTIVE.

We illustrate a very remarkable locomotive, which has been constructed from the designs of M. Estrade, a French engineer. This engine was exhibited last year in Paris. Although the engine was built, M. Estrade could not persuade any railway company to try it for him, and finally he applied to the French government, who have at last sanctioned the carrying out of experiments with it on one of the state railway lines. The engine is in all respects so opposed to English ideas that we have hitherto said nothing about it. As, however, it is going to be tried, an importance is given to it which it did not possess before; and, as a mechanical curiosity, we think it is worth the consideration of our readers.

In order that we may do M. Estrade no injustice, we reproduce here in a condensed form, and in English, the arguments in its favor contained in a paper written by M. Max de Nansouty, C.E., who brought M. Estrade's views before the French Institution of Civil Engineers, on May 21, 1886. M. Nansouty's paper has been prepared with much care, and contains a great deal of useful data quite apart from the Estrade engine. The paper in question is entitled "Memoire relatif au Materiel Roulant a Grand Vitesse," D.M. Estrade.

About thirty years ago, M. Estrade, formerly pupil of the Polytechnic School, invented rolling stock for high speed under especial conditions, and capable of leading to important results, more especially with regard to speed. Following step by step the progress made in the construction of railway stock, the inventor, from time to time, modified and improved his original plan, and finally, in 1884, arrived at the conception of a system entirely new in its fundamental principles and in its execution. A description of this system is the object of the memoir.

The great number of types of locomotives and carriages now met with in France, England, and the United States renders it difficult to combine their advantages, as M. Estrade proposed to do, in a system responding to the requirements of the constructor. His principal object, however, has been to construct, under specially favorable conditions, a locomotive, tender, and rolling stock adapted to each other, so as to establish a perfect accord between these organs when in motion. It is, in fact, a complete train, and not, as sometimes supposed, a locomotive only, of an especial type, which has been the object he set before him. Before entering into other considerations, we shall first give a description of the stock proposed by M. Estrade. The idea of the invention consists in the use of coupled wheels of large diameter and in the adoption of a new system of double suspension.

The locomotive and tender we illustrate were constructed by MM. Boulet & Co. The locomotive is carried on six driving wheels, 8 feet 3 inches in diameter. The total weight of the engine is thus utilized for adhesion. The accompanying table gives the principal dimensions:

TABLE I.