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Memoirs of a Trait in the Character of George III. of these United Kingdoms/Appendix 4

No. 4.

A LETTER FROM LIEUTENANT A. HOWE, ON THE COMPARATIVE MERITS OF THE LUNAR PROCESS, FOR FINDING THE LONGITUDE, AND THAT BY CHRONOMETRY.



As it occurred to the Author; a fresh water sailor (like Mr. Croker) that improvements in the instruments, and increased facilities in practice, may have made Lunar observations more available than when this pamphlet was published, above sixty years ago; with a view to be better informed of the present state of these concerns in the Navy, he wrote to an intelligent Officer (Lieutenant Alexander B. Howe) whom he knew to be of great experience. The following extract from the answer of that Gentleman, written in December, 1830 (see page 183) treats the question distinctly, and may be thought to set it at rest: except with those few who can no more be expected to part with a preconceived opinion than an old scholiast would to undervalue the logic of Thomas Aquinas.

In reply to your enquiry, I have much pleasure in stating, that in the opinion of the most able, scientific and successful nayigators, the invaluable invention of Mr. John Harrison stands unrivalled by any other mode of ascertaining the Longitude at sea, and that for the best reasons. In the first place there are many men of great science who, from some personal imperfection, cannot accurately measure the distance between the moon and the sun, or a star, where a trifling error is of great consequence; when he must of course depend for accuracy on another. You will at once see how far this goes in comparison; and it is not unusual for the nicest observers to express their doubts on that point; and in a fleet, the result of the observations on board different ships will often vary from thirty to forty miles, under the most favourable circumstances. Besides it not unfrequently happens in tropical climates, that the best practical observer is unwell and cannot act, when the desired object becomes very uncertain; but not so with the chronometer, for any person who can take an altitude, can determine the Longitude; and I have never known a navigator, who had any opinion worth notice that has not expressed his entire confidence in. those admirable machines, and depended on his Lunar observations in proportion to their approach to the Timepiece, to which he has always looked as his surest guide.

This I am quite sure is not only my opinion, from positive experience, but that of every Officer in the Navy, who has witnessed the amazing accuracy of the chronometer and the ease with which it is kept.—In a conversation I once had on the subject, with the then oldest Captain in the East India service, he expressed his apprehensions that the rising Officers in that service would be induced to lay aside their astronomical acquirements altogether, as the chronometer rendered navigation so easy that a woman could take a ship to Calcutta. He had been fifty years in that service, and largely expatiated on the improvements in navigating since the introduction of timepieces. This was in 1812, and he spoke from an experience of thirty years practice with chronometers.

Some remarks are added, denoting Lieutenant Howe's dissent from Mr. Croker's opinion on the points at issue; who he thinks lays more stress on scientific accomplishments, than on the practical utility that outweighs them.