. Annals of Philosophy. 184 Rev. J. J. Conybeare on the [March, the commanders, miss the harbour altogether, the loss in conse- quence is not chargeable upon the entrance. Entrances that face the calmest quarter, and that do not receive the surf, are at right angles, or nearly so, to the main shore. Let A, fig. 2, be such an en- trance to the harboui B, facing the high shore o s; a b is the main pier, and n m the inner pier. The exterior lines of approach, e b, c b, are obtained by allowing such space in front of the shore a t, i1:, and g h, as will keep ships sailing on these lines from rocks
. Annals of Philosophy. 184 Rev. J. J. Conybeare on the [March, the commanders, miss the harbour altogether, the loss in conse- quence is not chargeable upon the entrance. Entrances that face the calmest quarter, and that do not receive the surf, are at right angles, or nearly so, to the main shore. Let A, fig. 2, be such an en- trance to the harboui B, facing the high shore o s; a b is the main pier, and n m the inner pier. The exterior lines of approach, e b, c b, are obtained by allowing such space in front of the shore a t, i1:, and g h, as will keep ships sailing on these lines from rocks and shallow water; and if they have within them 146° 15', then a vessel can reach the pier- head b in any wind. But as the side c is open in strong sea gales, vessels are some times carried too far past the head b to turn into the harbour-mouth A ; and the same happens in gales out of the harbour-mouth A : vessels so driven aside are forced upon the contiguous rocks or sandy shore, and are destroyed or much injured. So it has happened after an entrance of this kind has been tried to a large harbour, and where money could be obtained, that outworks have been erected on the exposed side c, which assimilate the principle of this entrance, when so modified, very closely with that of the first kind of entrance. I am, Sir, yours, &c. J. B. Article V. On the Geology of Devon and Cornwall. By the Rev. J. J. Conybeare, MGS. (To the Editor of the Annals of Philosophy.) MY DEAR SIR, BathEaston, Feb. 2, 1823. The notice of such geological travellers as first visited Corn- wall and Devonshire was of course most strongly attracted by those which may be termed their metalliferous districts, and these still do and must always continue to present the most immediate and interesting objects of such research. Soon also the attention was directed to such points of the coast as are. Please note that these images are extracted from scanned page images that may have been digitally enh
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