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Such publications ought to be without a trace of exaggeration, and furnish only data on which the mariner may with perfect confidence rely. My object in extending these observations over so long a period was to make evident to all how fallacious it would be, and how mischievous it might be, to draw general conclusions from observations made in weather of great acoustic transparency.

Thus ends, for the present at all events, an inquiry which I trust will prove of some importance, scientific as well as practical. In conducting it I have had to congratulate myself on the unfailing aid and coöperation of the Elder Brethren of the Trinity House. Captain Drew, Captain Close, Captain Were, Captain Atkins, and the deputy-master, have all, from time to time, taken part in the inquiry. To the eminent arctic navigator, Admiral Collinson, who showed throughout unflagging, and, I would add, philosophic interest in the investigation, I am indebted for most important practical aid; he was almost always at my side, comparing opinions with me, placing the steamer in the required positions, and making, with consummate skill and promptness, the necessary sextant observations. I am also deeply sensible of the important services rendered by Mr. Douglas, the able and indefatigable engineer; of Mr. Ayres, the assistant engineer; and of Mr. Price Edwards, the private secretary of the deputy-master of the Trinity House.

The officers and gunners at the South Foreland also merit my best thanks, as also Mr. Holmes and Mr. Laidlaw, who had charge of the trumpets, whistles, and siren.

In the subsequent experimental treatment of the subject I have been most ably aided by my excellent assistant, Mr. John Cottrell.


By J. R. BLACK, M. D.

IF there is any one disease that the diligent brain-worker, a little past middle life, has reason to fear, it is apoplexy. Although statistical evidence is wanting, the experience of the physician confirms the popular belief that more of our distinguished men are carried off by this disease, or by one of its sequels, paralysis, than by any other cause. The influences which tend to produce such a result, and the best means of avoiding them, are the objects we propose briefly to discuss.

A middle-aged physician said one day to the writer: "As I was walking down the street after dinner I felt a shock in the back of my head, as if some one had struck me; I have not felt well since. I fear I shall die, just as all my ancestors have, of paralysis. What shall I