5 86 



NA TURE 



[October 28, 1922 



et sp. now, from the Miocene of Wyoming. M. R. 

 Thorpe describes a " New genus of Oligocene Hyte- 

 nodontidae, " from South Dakota, under the name of 

 Neohvsenodon. He also discusses the " Oregon 

 Tertiary Canidae " and " A new Merycoidon " as 

 well as " Arseocyon, a probable old world migrant." 

 The last-named, founded on a jaw from the Middle 

 Pliocene of Oregon, has its nearest ally in Simocyon 

 primigenius, Roth, from the Pikermi beds near 

 Athens, and should it prove to be a derivative of 

 purely American ancestry it will, the author con- 

 siders, be one of the most remarkable cases of 

 convergence known to the science of vertebrate 

 paleontology. Finally, in a more lengthy paper Mr. 

 Thorpe describes " Some Tertiary Carnivora in the 

 Marsh Collection," including new forms. 



Rain-producing Influences in South Australia. 

 — From an examination of the rainfall records and 

 other evidence in South Australia, Mr. E. T. Quayle 

 has come to the conclusion that there is an area of 

 marked rainfall improvement lying south-east from 

 Lake Torrens, where in places it ranges as high as 

 20 per cent. In the Proceedings of the Royal Society 

 of Victoria, 34 (N.S.), Pt. II., Mr. Quayle discusses 

 the reasons of this improvement and its bearing on 

 the reclamation of arid areas in the interior. The 

 area of improvement in South Australia is con- 

 tinuous with a similar one in Victoria, and both are 

 in contrast to areas of marked decrease to the north. 

 Irrigation as a source of improved rainfall cannot 

 operate in South Australia, for it has made practically 

 no progress. Mr. Quayle finds the causes in changes 

 in vegetation, due to settlement, and to variations 

 in the water supply of the great inland lakes. From 

 various data it would appear that Lake Torrens and 

 Lake Frome are now impounding more water than 

 formerly, but quantitative data are difficult to 

 obtain. Certain places to the south-east or lee of 

 the lake show increased rainfall in recent years, while 

 places beyond its influence show a decrease. The full 

 cause of the increase of water in these lakes is not 

 clear, but Mr Quayle considers that the substitution 

 of cereal crops or grass for Mallee scrub leads to a 

 marked increase in rainfall. The destruction of 

 forest trees and the extension of pastoral lands are 

 aids in local rain production. This matter is of so 

 much importance that it is to be hoped that investiga- 

 tions on a larger scale will be undertaken. 



The Lignite of the Lough Neagh Clays. — 

 Evidence is accumulating to show that the Lough 

 Neagh Clays in the counties of Tyrone and Antrim are 

 of Oligocene rather than Pliocene age. The recent 

 deep boring at Washing Bay has yielded to Prof. 

 Johnson and Miss J. G. Gilmore (Sci. Proc. R. Dublin 

 Soc, vol. 17, p. 59, 1922), through the cores preserved 

 by the Geological Survey, material that calls forth the 

 following interesting remark : " It needs little imagina- 

 tion to picture the presence of forests of Sequoia in 

 N. Ireland, possibly contemporaneous with those in 

 S. Devon at Bovey Tracey, the shores of the Baltic, 

 the Rhine valley, Saxony, Silesia, and S. France. We 

 may yet find in Ireland large deposits of lignite or 

 brown coal of economic value like those abroad." 



The Statement of Crystal-symmetry. — Numer- 

 ous minerals are known, the normal crystals of 

 which indicate, on physical measurement, a certain 

 type of symmetry, while the results of treating them 

 with solvents lead to their being placed in another 

 of the thirty-two crystallographic classes. A latent 

 symmetry is thus revealed. E. T. Wherry (Amer. 

 Journ. Sci., vol. 204, p. 237, Sept. 1922) styles such 

 crystals amphisymmetric, and regards the symmetry 

 determined with the goniometer as that of the structure 



built up by the atoms or molecules, and the latent 

 symmetry as that of the separate atoms or molecules, 

 with their attached electrons. This matter is in- 

 geniously stated on p. 241. A halogen atom in 

 sylvine, for example, may receive an electron from a 

 potassium atom, and may then, as a complete octet, 

 be capable of taking its place in a holosymmetric 

 structure. When, however, it is attacked by a 

 solvent, its low surface-symmetry, due to the presence 

 of one electron of metal and seven of halogen, is 

 revealed as the latent symmetry of the substance. 

 Both classes of symmetry should be mentioned in the 

 description of the crystal. Sylvine might thus be 

 described as " Cubic ; structurally holosymmetric ; 

 latently gyroidal," or " Cubic, structurally of class 32 

 latently 29." A useful list of amphisymmetric 

 substances is given by the author, including some noi 

 known as minerals. 



Insulation Testing. — Messrs. Evershed anc 

 Vignoles, Ltd., of Acton Lane Works, Chiswick, have 

 produced a new insulation tester which possesses 

 several advantages over the older types. Mr. Ever- 

 shed, who was the first to make a testing set consisting 

 of a small hand dynamo and an ohmmeter, has pro- 

 duced many improvements on the original set during 

 the last thirty years. His greatest improvement was 

 when he made a " one-box " instrument in 1903 and 

 raised the pressures produced by the hand dynamo 

 to 500, 1000, and even higher voltages. This instru- 

 ment is called the " megger " and has a world-wide 

 reputation. The new instrument is called the " meg 

 insulation tester. As its weight is only 7 lb. and 

 its dimensions are only 5J x 7J x t>\ inches, it is much 

 lighter and smaller than any similar instrument. 

 The case is made of cast aluminium, one end of which 

 is formed of an oil-tight gear box. It is always ready 

 for use and will stand rough usage. A free-wheei 

 device protects the gear from damage and prevents 

 the armature from being turned the wrong way. At 

 100 rev. per. min. it generates 500 volts, and consider- 

 ing its size its efficiency is most satisfactory. The 

 price is only about half the price and the weight is 

 less than half the weight of the well-known " megger ' 

 testing set. 



Heating and Ventilation in Passenger Ships.— 

 With the general advance of scientific progress many 

 of the discomforts of sea life have been eliminated 

 Distilling ensured a plentiful supply of fresh water ; 

 electricity solved the problem of lighting, refrigeration 

 that of food preservation. The accommodation ol 

 our big ships is often and rightly described as palatial 

 If there is any problem that has lagged behind it is 

 that of the ventilation and heating of passenger ships 

 a subject which was dealt with in a paper read by 

 Mr. J. L. Musgrave at the Institution of Heating and 

 Ventilating Engineers on October 11. The problem 

 is admittedly a difficult one. Not only have large 

 numbers of passengers to be accommodated in limited 

 spaces but the conditions of sea life change from day 

 to day. Then, too, odours from the machinery spaces, 

 from the paintwork, store-rooms, kitchen, bathrooms, 

 etc., have to be prevented from reaching the living 

 spaces, and at the same time an ample supply of fresh 

 air, heated or cooled as the case may be, has to be 

 kept in circulation throughout dining saloons and 

 cabins. In his paper the author referred to these 

 things and gave it as his opinion that though ship- 

 building firms employ experienced men to design the 

 ventilating and heating arrangements, the co-opera- 

 tion of the fully-qualified heating and ventilating 

 engineer at an early stage of the design of the ship 

 would lead to more satisfactory results, and that 

 expenditure on improved ventilation would prove a 

 profitable investment. 



NO. 2765, VOL. I ioj 



