Page:Travels to Discover the Source of the Nile - In the Years 1768, 1769, 1770, 1771, 1772, and 1773 volume 1.djvu/472

360 some of them near the surface, though the breakers do not appear upon them, partly owing to the waves being steadied by the violence of the current, and somewhat kept off by the island. This dangerous error is, probably, owing to the draughts being composed from different journals, where the pilot has had different ways of measuring his distance; some using forty-two feet to a thirty-second glass, and some twenty-eight, both of them being considered as one competent division of a degree; the distances are all too short, and the soundings, and every thing else, consequently out of their places.

has to navigate in the Abyssinian side of the channel, will do well to pass the island Dahalac on the east side, or, at least, not approach the outmost island, Wowcan, nearer than ten leagues; but, keeping about twelve leagues meridian distance west of Jibbel Teir, or near mid-channel between that and the island, they will then be out of danger; being between lat. 15° 20' and 15° 40', which last is the latitude, as I observed, of Saiel Noora, and which is the northern island, we saw, three leagues off Ras Antalou, the northmost cape of Dahalac.

at our entering into the port of Dobelew on the 14th, and our going out of it on the 17th, we found a tide running like a sluice, which we apprehended, in spite of our sails being full, would force us out of our course upon the rocks. I imagine it was then at its greatest strength, it now being near the equinoctial full moon. The channel between Terra Firma and the island being very narrow, and the influence of the sun and moon then nearly in the equator,