It is, perhaps, more difficult to write accurate history than anything else, and this is true not only of nations, kings, politicians, or wars, but of events and things witnessed or called into existence in every-day life. In _The Engineer_ for September 17, 1880, we did our best to place a true statement of the facts concerning the Rocket before our readers. In many respects this was the most remarkable steam engine ever built, and about it there ought to be no difficulty, one would imagine, in arriving at the truth. It was for a considerable period the cynosure of all eyes. Engineers all over the world were interested in its performance. Drawings were made of it; accounts were written of it, descriptions of it abounded. Little more than half a century has elapsed since it startled the world by its performance at Rainhill, and yet it is not too much to say that the truth--the whole truth, that is to say--can never now be written. We are, however, able to put some facts before our readers now which have never before been published, which are sufficiently startling, and while supplying a missing link in the history of the locomotive, go far to show that much that has hitherto been held to be true is not true at all. When the Liverpool and Manchester Railway was opened on the 15th of September, 1830, among those present was James Nasmyth, subsequently the inventor of the steam hammer. Mr. Nasmyth was a good freehand draughtsman, and he sketched the Rocket as it stood on the line. The sketch is still in existence. Mr. Nasmyth has placed this sketch at our disposal, thus earning the gratitude of our readers, and we have reproduced as nearly as possible, but to a somewhat enlarged scale, this invaluable link in the history of the locomotive. Mr. Nasmyth writes concerning it, July 26, 1884: "This slight and hasty sketch of the Rocket was made the day before the opening of the Manchester and Liverpool Railway, September 12, 1830. I availed myself of the opportunity of a short pause in the experimental runs with the Rocket, of three or four miles between Liverpool and Rainhill, George Stephenson acting as engine driver and his son Robert as stoker. The limited time I had for making my sketch prevented me from making a more elaborate one, but such as it is, all the important and characteristic details are given; but the pencil lines, after the lapse of fifty-four years, have become somewhat indistinct." The pencil drawing, more than fifty years old, has become so faint that its reproduction has become a difficult task. Enough remains, however, to show very clearly what manner of engine this Rocket was. For the sake of comparison we reproduce an engraving of the Rocket of 1829. A glance will show that an astonishing transformation had taken place in the eleven months which had elapsed between the Rainhill trials and the opening of the Liverpool and Manchester Railway. We may indicate a few of the alterations. In 1829 the cylinders