December 19, 19 12] 



NATURE 



453 



Sussex. The first of these was the brown-veined 

 orchid, Orchis purpurea, found in the Ouse district, 

 near Lewes, in the month of May, by Mr. Herbert 

 Jenner, of Lewes. This interesting find was the pre- 

 lude of another of perliaps even greater interest, for 

 in the month of June the author found a specimen 

 of the rare lizard orchid, Orchis hircina, in the Cuck- 

 mere district near Eastbourne. The author's collec- 

 tion of photographs at present consists of thirty-fhree 

 species and varieties out of a possible forty-four. — 

 Prof. W. A. Herdman : Spolia Runiana, L, the 

 Hebridean Diazona described as "Syntethys," and 

 other rare or interesting animals obtained on the 

 cruise of the S.Y. Rttna in 1912. The chief forms 

 discussed were : — (i) The giant sea-pen, Funiculina 

 quadrangularis; (2) the pelagic Tunicate, Doliolum 

 tritonis ; and (3) the large green compound ascidian, 

 described by Forbes and Goodsir in 185 1 as Syntelhys 

 hebridicua, but now shown to be the same as Diazona 

 violacca, Savigny, from the Mediterranea;i. 



Physical Society, November 22. — Prof. L. H. Lees, 

 F.R.S., vice-president, in the chair. — Prof. E. G. 

 Coker : a column-testing machine. The conditions of 

 fi.xture of the ends of columns, and the large influence 

 this has upon their strength, generally make it neces- 

 sary to use special testing machines for these mem- 

 bers, in which the end plates applying the load are 

 accurately parallel, and remain so during a test. If 

 only rough measurements of the load are required 

 this offers no serious difficulty, but accurate measure- 

 ment involves elaborate mechanical devices, some of 

 which are briefly referred to in the paper. This diffi- 

 culty is overcome in a simple manner by supporting 

 one pressure plate by two or more annular diaphragms 

 spaced at considerable intervals, and clamped at their 

 outer edges to a fixed casing in such a manner that 

 only one degree of freedom is possible. This con- 

 struction is carried out in the machine described in 

 the paper.— C. E. Larard : The law of plastic flow of 

 a ductile material and the phenomena of elastic and 

 plastic strains. The author gave an account of the 

 twisting to destruction at a uniform angular velocity 

 of a cylindrical steel specimen 3 in. diameter, and of 

 his deductions from the experimental data. The fol- 

 lowing deductions w-ere made : — (i) The rate of in- 

 crease of the torque with the time varies inversely 

 as the time. (2) The acceleration of the torque velo- 

 city which is negative or, as it may be called, the de- 

 celeration, varies therefore inverse! v as the square of 

 the time. (3) The variables, time (, and torque T, are 

 connected by the compound- interest law. More 

 exactly t + t„ = ai>>'^, where t^ is a time constant. Cor- 

 responding results in terms of the angle of torsion 

 and T obviously followed, since = ut, where t^' is the 

 angular rate of straining. The author next proceeded 

 to summarise certain other conclusions he has formed 

 as a result of many experiments extending over five 

 years, illustrating his arguments by meansof original 

 diagrams, but reserving the full account for later 

 publication. — C. E. Larard : Kinematograph illustra- 

 tions of the twisting and breaking of large wrought- 

 iron and steel specimens. The tests illustrated the 

 Northampton^ Institute testing machine in operation, 

 showing torsion tests on the following : — fi) A piece 

 of mild steel, 2J in. diameter. (2) A piece of wrought- 

 iron of the same dimensions. (3) A wrought-iron 

 shaft, 2^ in. square. (4) A rectangular bar of steel, 

 3i in. bv li in. (s.) A steel tube, 3^ in. diameter, with 

 the wall I in. thick. (6) A tension test showing the 

 development of the Liider lines. 



Zoological Society, November 26.— Dr. A. Smith 

 Woodward. F.R.S., vice-president, in the chair. — 

 E. S. Goodrich : The structure of bone in fishes : a 

 contribution to pateohistologv. A microscopic 



NO. 2251, VOL. go] 



examination of the bone of the Actinopterygian fishes 

 showed that in those groups which are provided with 

 lepidosteoid ganoid scales (Amioidei [Protospondyli] 

 and Lepidosteoidei [AetheospondyliJ) the character- 

 istic lepidosteoid histological structure extended 

 throughout the endoskeleton as well as the dermal 

 bones. No other fishes are known to have this lepido- 

 steoid structure, either in the scales or in the skeleton. 

 — G. VV. Smith and Dr. E. H. J. Schuster: Land 

 crayfishes of Australia. This paper dealt with the 

 Engceus, a group of Victorian and Tasmanian cray- 

 fishes, which have forsaken the water and excavate 

 burrows in damp soil. In certain mining districts on 

 the west coast of Australia they do much damage to 

 the artificial water-courses by riddling through the 

 banks and dams and causing them to collapse. 

 Although the tunnel leading to the heart of the burrow- 

 is free from water, there is always water in the circu- 

 lar chambers at the end where the crayfish lives. 

 In a former paper it was suggested that these cray- 

 fishes of the genus Engseus are derived from the 

 genus Parachseraps, which has spread from Western 

 Australia into the desert regions of the centre, and is 

 now found in all parts of continental .Australia ; but 

 conclusive evidence is brought forward in this paper 

 to show that Engseus is derived from the south- 

 eastern and Tasmanian genus Astacopsis, and that its 

 superficial resemblance to Parachaeraps is due to con- 

 vergence owing to similar habits. — Dr. C. L. 

 Boulenger : The Myzostomida collected by Mr. Cyril 

 Crossland in the Red Sea in 1905. — Hon. P. A. 

 Methuen : Description of a hew Amphipod, belonging 

 to the family Talitridae, obtained in the Woodbush 

 district of northern Transvaal. — B. F. Cummings : 

 Some points in the anatomy of the mouth-parts of 

 the Mallophaga. 



Geological Society, December 4. — Dr. Aubrey 

 Strahan, F.R.S., president, in the chair. — J. E. Marr : 

 The Lower Palasozoic rocks of the Cautley district 

 (Yorkshire). The succession in this district is clearer 

 than in the Lake District, and it is suggested that 

 it be adopted as the type sequence for the .Ashgillian 

 beds of the north of England. — E. S. Cobbold : (i) 

 The trilobite fauna of the Comley Breccia-bed (Shrop- 

 shire). A trilobitic fauna from the matrix of a breccia 

 of Middle Cambrian age, found near Comley Brook, 

 is described. The fossils indicate an horizon that is 

 probably equivalent to a part of the Paradoxides-tessini 

 zone of Scandinavia. As they are distinct from those 

 of the Quarry-Ridge Grits of Comley, which are also 

 basal but rest upon Lower Cambrian limestones, the 

 inference is drawn that the tw-o deposits are separated 

 by a distinct interval of Cambrian time. (2) Two 

 species of Paradoxides from Neve's Castle (Shrop- 

 shire). Portions of two species of Paradoxides, col- 

 lected in 1892 by Mr. J. Rhodes, are figured. These 

 are referred to P. hicksi, Salter, and to a new variety 

 of P. bohemicus. Boeck. Species of Agnostus, 

 Ptychoparia (Liostracus), Agraulos, Hyolithus, and 

 Acrotreta occur in the same rock-fragments, but are 

 not sufficiently well preserved for specific determina- 

 tion. 



Mathematical Society, December 12.— Prof. A. E. H. 

 Love, president, in the chair. — Dr. H. F. Baker (re- 

 tiring president) : Presidential address on recent ad- 

 vances in the theory of surfaces.. — H. E. J. Curzon : 

 A connection betw'een the functions of Hermite and 

 those of Legendre. — G. H. Hardy : .A.n extension of a 

 theorem on oscillating series. — H. R. Hass4 : The 

 equations of the theory of electrons transformed rela- 

 tive to a system in accelerated motion. — E. W. 

 Hobson : The convergence of series of orthogonal 

 functions. — J. McDonnell : Mersenne's primes. — L. J. 

 Mordell : The diophantine equation y- = x^ + k. — 



