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NOTES AND ILLUSTRATIONS.

With refpedt to places in the torrid zone, there wasanother refource for determining the latitude. This wasby obferving the time of the year when the fun was verticalto any place, or when bodies that flood perpendicular tothe horizon had no fhadow at noon-day; the fun’s diltancefrom the Equator at that time, which was known from theprinciples of aftronomy, was equal to the latitude ofthe place. We have inftances of the application of thismethod in the determination of the parallels of Syene andMeroe . The accuracy which this method would admitof, feems to be limited to about half a degree, and thisonly on the fuppofition that the obferver was ftationary;for if he was travelling from one place to another, andhad not an opportunity of correcting the obfervation of oneday by that of the day following, he was likely to deviatemuch more confiderably from the truth.

With refpeCt to the longitude of places, as eclipfes ofthe moon are not frequent, and could feldom be of ufe fordetermining it, and only when there were aftronomers toobferve them with accuracy , they may be left out of theaccount altogether when we are examining the geographyof lemote countries. The differences of the meridians ofplaces were therefore anciently ascertained entirely by thebearings and diflances of one place from another, and ofconfequenee all the errors of reckonings, Surveys , anditineraries, fell chiefly upon the longitude, in the famemanner as happens at prefent in a fhip which has nomethod of determining its longitude, but by comparingthe dead-reckoning with the observations of the latitude;though with this difference, that the errors, to which themoll; Skilful of the ancient navigators was liable, were fargreater than what the molt ignorant Ihip-mafter of modern !times , provided with a compafs, can well commit. Thelength of the Mediterranean meafured , in degrees oflongitude , from the Pillars of Hercules to the Bay of Iffus,is lefs than forty degrees; but in Ptolemy ’s maps it ismore than lixty, and, in general, his longitudes, countingfrom the meridian of Alexandria, efpecially toward the

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