We Certainly Can Observe With Greater Accuracy Through The Telescope, Than With The Common Sight, When The Ship Is Sufficiently Steady.

The use of the telescope is found difficult at first, but a little practice will make it familiar.

By the assistance of the watch, we shall be able to discover the greatest error this method of observing the longitude at sea is liable to; which at the greatest does not exceed a degree and a half, and in general will be found to be much less. Such is the improvement navigation has received by the astronomers and mathematical instrument- makers of this age; by the former from the valuable tables they have communicated to the public, under the direction of the Board of Longitude, and contained in the astronomical ephemeris; and by the latter, from the great accuracy they observe in making instruments, without which the tables would, in a great measure, lose their effect. The preceding observations were made by four different sextants, of different workmen. Mine was by Mr Bird; one of Mr Wales's by Mr Dollond; the other and Mr Clerke's by Mr Ramsden; as also Mr Gilbert's and Smith's, who observed with the same instrument.

Five tolerably fine days had now succeeded one another. This, besides giving us an opportunity to make the preceding observations, was very serviceable to us on many other accounts, and came at a very seasonable time. For, having on board a good quantity of fresh water, or ice, which was the same thing, the people were enabled to wash and dry their clothes and linen; a care that can never be enough attended to in all long voyages. The winds during this time blew in gentle gales, and the weather was mild. Yet the mercury in the thermometer never rose above 36; and was frequently as low as the freezing point.

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