On the other hand, by almost abandoning the present modes, and adopting measures which I shall point out presently, adapted to the new circumstances, a much greater degree of certainty and accuracy may be attained than is now even sought for. I have had the best advice on these points, both astronomical and nautical: the Astronomer Royal, Mr. Airy, who both as a man of science and a practical man, and by his official position, is the first authority on such matters, and Professor Smyth, of the Edinburgh Observatory, Captain Beecher of the Admiralty, and several other scientific naval men, have assisted me; and, under their advice, instruments are being constructed, and a system devised, which will admit of continuous observations being made with great accuracy at all times of the day, and particularly at night, and by means of which also a continuous correction of the ship’s compasses with the most minute accuracy can be kept up, and her position be ascertained with almost the same accuracy as a point on land; and I have their authority for saying that such improved means are desirable, and are attainable. The importance and advantage of continuous observation throughout the twenty-four hours, whenever a glimpse can be obtained of any object which will answer the purpose, and even when the horizon is invisible, may not at first be evident, but it cannot be over-estimated. An exact knowledge of the ship’s movements will be soon acquired that would almost replace observation, and the average of numerous observations secures an accuracy which cannot be approached by any other method. By a careful and continuous comparison of the exact distances run, with accurate records of the speed of the engine and of the ship through the water, registered by good instruments (the performance of which has been tested, and which are being made), and having proper reference to the varying draught of water of the vessel, the most precise measure of the speed of the vessel through the water can be learnt; and by careful observation of the force and direction of the wind, the effect of any given wind, and an accurate measure of her drift or lee-way, may be obtained; and then, by adhering strictly, without regard to wind or weather, to a course previously laid down on good charts, having upon them the sets of currents, as already observed, the true position of the ship may be determined at any moment, and there need never be the slightest hesitation, or any time or distance lost by doubts. In addition to the instruments above named, I hope to be able to provide the means of sounding at moderate depths while the ship is going her full speed.