IN Smiles' "Lives of the Engineers," in the volume of the 1874 edition devoted to George and Robert Stephenson, will be found a very small engraving which is a longitudinal section of Murdock's locomotive. In the "Life of Trevithick," by his grandson, and published by Messrs. Spon, in 1872, will be found a small section of the machine. We are not aware of the existence of any other section of this little engine, save that which we publish on next page. The machine is the property of Mr. Murdock, manager of the Sun Foundry, Leeds, and grandson of William Murdock, the friend of Watt, and the maker of the little locomotive in question. Smiles gives no dimensions or details. Mr. Murdock has, however, recently taken the engine to pieces, and had a drawing made from it fully dimensioned, and we are indebted to him for a tracing from this drawing, by the aid of which our engraving has been prepared. Mr. Murdock has had the engine under steam, and found that it readily made one hundred revolutions a minute when supported with the driving wheels off the ground. It is one of the most interesting mechanical relics in existence; for there is no reason to doubt that it is the first locomotive steam engine ever made in England. The first locomotive ever constructed was built by Cugnot, a French engineer. The original model was made in 1763, and the machine itself was tried in 1769. It was not successful because the boiler was too small. In 1772 Oliver Evans, in America, invented a steam carriage to travel on common roads. In 1784 William Symington made, it is said, a model of a locomotive in Scotland, and in the same year Murdock produced the model we illustrate. It was not until 1802 that Richard Trevithick, Murdock's pupil, took up the subject. Those who wish to learn what be did will find it fully recorded in "The Life of Trevithick," referred to above.

The Murdock model has been exhibited many times, and it is to be regretted that it does not now repose in some museum where it could be seen, while it remained in perfect safety. It consists of a flat board, at one end of which is a wooden upright, on which is pivoted a wooden beam. The cylinder is placed underneath the other end of this beam. This slide valve is actuated by a tappet motion, the beam striking it up and down alternately at each end of the stroke. The connecting rod has a transverse joint near the top, intended, no doubt, to compensate for imperfect workmanship, in the same way that Watt used a universal joint in his earlier connecting rods, as may be seen, for instance, in a Watt engine which is, or was until a very recent date, at work at Messrs. Frost's rope works in Bermondsey. The disk seen round the vertical pivot of the steering wheel is a leaden weight, apparently put on to keep the front of the engine down, and so make it steer better. The boiler is of copper. The details are too clearly shown to make further description necessary.—The Engineer.