294 



NATURE 



[August 25, 1923 



from animals, mostly Indian, in the Zoological 

 Garden, Calcutta. One of the most interesting 

 records is that of full-si^jed specimens of Ascaris 

 lumhricoides in squirrels. The authors have com- 

 pared these specimens with others from man and 

 from an Indian wild pig — paying particular attention 

 to the characters of the lips, of tne posterior end of 

 the male, and of the eggs — and they conclude that 

 all belong to the same species. A ncylostoma duodenale 

 is recorded from the tiger, the specimens being some- 

 what smaller than those from man, as has been noted 

 in regard to examples previously found in the tiger. 

 Necator americanus was found in a new host, namely, 

 a young African rhinoceros which was captured in 

 Tanganyika Territory and had lived in the Calcutta 

 Zoological Garden only a very short time. Two 

 larvae taken from a prawn are tentatively referred to 

 the genus Eustrongylides, and are apparently the 

 first examples of the genus to be recorded from an 

 invertebrate. 



Fossil Barnacle.s of India. — The receipt of fresh 

 material at the Natural History Museum has led 

 Mr. T. H. Withers to undertake a revision of the 

 Fossil Balanomorph Barnacles from India and the 

 East Indian Archipelago {Rec. Geol. Surv. India, 

 vol. liv). Five species in all are described, three 

 being new, but amongst them the Balanus tintin- 

 nabulum, of Linne, although often cited in literature, 

 was not to be found, notwithstanding its occurrence 

 in the modern Indian Ocean fauna. One of the new 

 species, Balanus javanicus, is closely allied to a recent 

 South African form, and another, B. indicus, to a 

 North Pacific species. 



Indian Tertiary Gastropoda. — A fourth, and 

 unhappily last, contribution on Indian Tertiary 

 Gastropoda comes from the pen of Mr. E. Vredenburg, 

 who did not, alas, live to revise the proofs. This 

 part includes the Olividae, Harpidae, Marginellidae, 

 Volutidaj, and Mitridae {Rec. Geol. Surv. India, vol. 

 liv.), and is on the same lines as its predecessors 

 {cf. Nature, May 6, 1922, p. 594). Most of the 

 species described are new and nearly all are excellently 

 illustrated. By an oversight the pre-Linnean name 

 Turricula of Klein, 1753, has been allowed to stand 

 in lieu of Vexillum, Bolten, 1798. 



The Geological Exploration of Africa. — The 

 progressive work of the Geological Survey of Nigeria 

 has already been referred to in Nature (vol. no, 

 p. 91, 1922). The fourth of the quarto bulletins, on 

 " The Northern Tinfields of Bauchi Province," price 

 105., has now been issued under the care of Dr. J. D. 

 Falconer, and its finish and style »f publication 

 testify to appreciative Government support. The 

 illustrations of heat-weathering and water-weathering 

 in granite increase our knowledge of " inselbergs," 

 and the solution-cave in the granite mass near 

 Gohar (PI. vi) will be a revelation to most geologists. 

 Dr. Falconer's discussion (p. 41) of the origin of the 

 fissures that carry tin ore in the region is of im- 

 portance in the question of batholitic intrusion gener- 

 ally. He shows how widely spread fracturing may 

 occur in advance of the magma rising from the depths, 

 and how intrusive breccias result from the breaking 

 off of abundant blocks from the zone of shattering. 

 The tin ore may have been introduced to a large 

 extent by vapours heralding the invasion, rather than 

 during the cooling of the " Younger Granite " mass. 

 In Uganda, where " mineralisation " is not obvious, 

 Mr. E. J. Way land is not so fortunate; he is of 

 necessity working with a temporary staff, and there 

 is a tendency to regard his Survev as a luxury. The 

 Annual Report for 1922 (Entebbe, 1923) shows a 



NO. 2808, VOL. 112] 



wide range of work, including researches on water- 

 supply, and we hope that it may be realised that a 

 Geological Survey, with a geographical as well as a 

 petrological outlook, forms the basis for the under- 

 standing of a country. The Geological Survey of 

 Tanganyika Territory, under Dr. E. O. Teale, has 

 issued (1922) what is called a " Final Report," in which 

 details of mineral samples are given, together with 

 some new points as to the Karroo flora of the district. 

 The recommendations show that hopes are enter- 

 tained of the establishment of a permanent Survey 

 Department, 



Contact Angles in Capillarity. — The modern 

 industry of ore flotation has its origin in some of the 

 comparatively obscure laws of surface tension, and 

 any observations which throw light on these laws 

 help to provide the industry with a firmer scientific 

 basis. Mr. R. Ablett's paper in the August issue of 

 the Philosophical Magazine deals with variation of 

 the contact angle of water with paraffin wax according 

 to whether the solid is stationary or is moving into 

 or out of the water. The wax is in the form of a 

 horizontal cylinder immersed to such an extent that 

 the two liquid surfaces at its sides are horizontal 

 right up to the solid. The angle of contact is then 

 104^°. On rotating the cylinder about its axis, the 

 angle at the side where the wax enters the water 

 becomes 113° and where it leaves the water 96", the 

 wax as it were dragging the meniscus with it. For 

 speeds exceeding 4 mms. per second these angles are 

 constant. The author ascribes the change of angle 

 to absorption or inhibition of the water by the wax. 



Theory of Ship Waves. — A contribution to this 

 subject, by Einar Hogner, has been published in the 

 Arkiv for Mateniatik, Astronomi och Fysik, Band 17, 

 No. 12. (Stockholm : Almquist and Wiksells Bok- 

 tryckeri A.-B. ; London : Wheldon and Wesley, Ltd.) 

 The aim of the paper is to investigate mathe- 

 matically the waves produced by a " forcive " travel- 

 ling with uniform velocity over a water surface ; 

 the investigation being confined to the waves in the 

 vicinity of two boundary planes radiating from the 

 " forcive " and forming an angle of i9°-28' with the 

 mid wake plane. The author briefly reviews the 

 mathematical explanation of the system of ship 

 waves developed by previous authors, and points out 

 that the theory so developed is valid only for waves 

 at great distances from the ship, and fails in proximity 

 of the boundary planes, where the wave amplitudes 

 become infinite. Furthermore, no waves exist outside 

 the boundary planes, as the approximations intro- 

 duced make the surface discontinuous at the bound- 

 aries. From his modified mathematical treatment, 

 which is given in full, the author deduces that the 

 resultant wave system inside the boundarv planes 

 can be considered as constituted by the superposition 

 of two different wave systems, the " transverse " 

 and " divergent." These two systems have a phase 

 difference of i/3rd of a wave length at the boundaries, 

 — a fact not hitherto noticed by previous writers on 

 this subject. The highest points of the outermost 

 waves are finite and situated at some distance inside 

 the boundary planes, and the resultant wa\e crests 

 form angles of 56°-44' with the mid-water plane. 

 The resultant wave systems inside and outside the 

 boundary planes join without discontinuity. The 

 system outside the boundar^'■ planes is simple. The 

 mutual situation and direction of the crests of the 

 different wave systems at the boundary are in general 

 found to be dependent on the acceleration of gravita- 

 tion, velocity of the forcive, and distribution of 

 pressure withiri the forcive ; and the direction de- 

 pends also on the distance from the forcive. 



