A Further Note on Sea-Birds

In a ‘Note on Sea-birds’ [JHS xcii (1972) 172–3] Miss Sylvia Benton comments on Mr J. K. Anderson's preceding Note, Θρᾷξ, Δυτῖνος, Καταρράκτης. But if we are to identify the species to which ancient names refer we must limit ourselves to those species which are now, or can be shown to have once been, present in Greece, and for this both accuracy of observation and a knowledge of the literature on the ornithology of Greece seem desirable. Miss Benton says: ‘A ship on which I was sailing was dive-bombed by Gannets just east of the harbour of Tinos: no doubt they were defending their nests on the cliffs’. But the Gannet (Sula bassana) is a bird of the North Atlantic which does not now nest, if it ever did, in the Mediterranean nor indeed south of 51° N. on the eastern coasts of the Atlantic, so that these dive-bombers, whatever they were, could hardly have been Gannets. There are only two authentic records of Gannets in Greece at all, in May 1853 and in April 1965 (A. Kanellis: Catalogus Faunae Graeciae; pars II Aves ed. W. Bauer, O. v. Helversen, M. Hodge, J. Martens. Thessaloniki, 1969).

The TRIAX 6 Element for Axisymmetric Analysis by the Matrix Displacement Method

The investigation of axisymmetric states of stress by the matrix displacement method may, in principle, be carried out as an ordinary exercise of three-dimensional analysis, using TETRA 4, TETRA 10 or other suitable elements. However, this approach is clearly not the most efficient by not taking advantage ab initio of the inherent simplifications arising in an axisymmetric state; this leads to an unnecessary inflation of the number of unknowns and complexity of the mesh. A number of techniques to deal with this limiting condition of a three-dimensional state have been developed at the ISD. The theory for one specific element, TRIAX 6 which evolves most naturally from the tapered TRIM 6 element analysed in the preceding note 8 is presented.