being much ſtronger than thoſe of copper, do not yield to that degree of preſſure which bends the others.
This ſource of error affords an additional reaſon why mariners ought to give the preference to the circle of reflexion, invented by Citizen Borda. The facility with which any errors that may ariſe from the graduation, are rectified by croſs obſervations, in the uſe of this inſtrument, gives it a very great ſuperiority over all others.
I regret that this valuable inſtrument, though ſo eaſy in its application, is not more generally in uſe. Each of our officers poſſeſſed one of them, and during the courſe of the expedition every one learnt to uſe it with certainty.
With a little practice an obſerver may take the longitude within 10, or 15,000 toiſes; and there is reaſon to believe, that when the lunar tables ſhall have attained a greater degree of perfection, the obſervations will approximate ſtill nearer to the truth.
Though the plants which I had collected at Teneriffe were very dry when we ſailed from that iſland, they were become much damaged by the moiſture which they had imbibed, during the time that we were between the Tropics, particularly at the lower part of the leaves, where the
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