in the subsequent trials, both vessels having set the whole of their sails, the _Archimedes_, carrying much more canvas than the _Widgeon_, on a run of 26 miles from Dover to Calais, close hauled, accomplished this distance in nine minutes less time than the _Widgeon_. Upon the return voyage to Dover, with a fresh breeze abeam and all sail set, the _Archimedes_, with a speed of ten knots per hour, performed the distance in five and a half minutes less time than the _Widgeon_. [Sidenote: and its results.] These experiments decided the practical value of the screw. They proved that the _Archimedes_ was slightly inferior to the _Widgeon_ in light airs, in calms, and in smooth water; but, as the steam power of the former was ten horses less, and her burthen 75 tons more than that of the _Widgeon_, it is evident that in _such_ vessels the propelling power of the screw alone was equal, if not superior, to the ordinary paddle-wheel. In this respect, therefore, Mr. T. P. Smith’s invention might be considered completely successful. It was evident from the second trial that, in steaming against even a light wind, the low masts and snug rig of the _Widgeon_ gave her an advantage over the _Archimedes_ with loftier masts and heavier rig; but, on the last two trials, the power of the sails operated favourably for the _Archimedes_, as she then beat the _Widgeon_, and made the passage between Dover and Calais in less time than it had ever previously been performed by any of Her Majesty’s mail packets. On this occasion the _Archimedes_ went from Dover to Calais in two hours and one minute, and returned in one hour and fifty-three and a half minutes.[141] Although the successful performances of the _Archimedes_ brought the screw into more general notice, it does not appear that she was ever employed as a trading vessel. After several experiments she lay for a long time in the East India Dock advertised for sale, and her spirited proprietors, who had been so instrumental in promoting the introduction of the screw-propeller, lost all the capital they had invested in this important undertaking. [Sidenote: The _Rattler_ and the _Alecto_, 1843.] As the _Widgeon_ and _Archimedes_ differed materially in size and form, an exact comparison could not be made by them between the performance of the screw and that of the paddle; but the result of these trials nevertheless showed (especially when the peculiar fitness of the screw for war purposes was taken into consideration) the propriety of having a further and fairer trial of this novel instrument. With this object in view the _Rattler_ was ordered to be built,[142] and, that the experiment might be conclusive so far as a trial could be made between two vessels, she was constructed on the same lines as the _Alecto_ (her after part being lengthened for the insertion of the screw), and fitted with engines of the same power, and on a plan which had been previously tried with paddle-wheel vessels.