Septembkr. 1911. 



KNOWLEDGE. 



351 



of treating gout by the application of radium emanation, and 

 it is claimed that the treatment has given good results. 



RADIUM IN URANIUM ORES.— An estimation of the 

 amount of radium present in various uranium ores has been 

 made by Messrs. Marckwald and Russell iCIieni. News, 1911. 

 C I II . 2 77 ) . who have taken the ionising power as a measure of the 

 radium. Comparing the ratio of the radium to uranium 

 with that of Joachimsthal pitchblende (taUen as 1001. they 

 have obtained a value of 98-1 for thorianite, and 101.5 for 

 African pitchblende, but for autunite values ranging from 

 20-7 to 68 • 0, although the ratio of ionium to uranium was 

 much more uniform in this mineral. Since the life of ionium 

 is not less than thirty thousand years, the conclusion is drawn 

 that autunite must be at least one hundred thousand years 

 old. and that, therefore, the relatively low values for the 

 radium ratio are not due to the radium being of recent 

 formation. It seems more probable that the physical structure 

 of autunite is responsible for the difference, and that owing to 

 its possessing a much more spongy texture than pitchblende and 

 thorianite. the radium and lead have been partially extracted 

 by water from the mineral. This view is supported by the 

 fact that there is only a slight occlusion of helium in autunite, 

 and by analogous results obtained in the examination of the 

 mineral rutherfordite. 



PROPERTIES OF METALLIC TITANIUM.— It is not 

 an easy matter to obtain the element titanium in a pure 

 condition, as is shown by the account given by Messrs. 

 Hunter and Jones {Rensselaer Polyt. Inst., No. 1, February 

 nth. 19111. of their attempts to prepare it. The products 

 obtained by reducing sodium, potassium, and barium titani- 

 tluorides with potassium in no instance contained more than 

 73-2 per cent, of titanium, while reduction of titanium oxide 

 by means of carbon invariably yielded products containing 

 upwards of five per cent, of carbon. Finally pure titanium 

 was prepared by heating together in a closed bomb a mixture 

 of titanium tetrachloride and metallic sodium, with the 

 greatest precaution to exclude all air. The reduction took 

 place almost instantaneously at a dull red heat, and products, 

 which on analysis showed from 99-9 to 100 per cent, of 

 titanium, were obtained. 



As thus prepared titanium was a hard brittle metal 

 resembling polished steel in appearance. It melted between 

 ISOQ- and 1850' C, and had a specific gravity of 4-50. It 

 could readily be forged. 



CHEMICALLY ACTIVE NITROGEN.— Pure nitrogen 

 that has been subjected to an electric discharge from a Leyden 

 jar undergoes a remarkable change, an account of which is 

 given by the Hon. R. J. Strutt. in a recent issue of the 

 Proceedings of the Royal Society (1911, LXXXV, 2191. The 

 gas after being removed from the region of the discharge 

 continues to glow during the process of returning to its 

 normal state. The glow is intensified by cold but diminished 

 by heat, and it is suggested that it may be due to the 

 dissociated atoms entering into combination again. 



In this chemically active condition, nitrogen forms a 

 compound with ordinary yellow- phosphorus, while a large 

 amount of the phosphorus is transformed into the red 

 modification during the reaction. It also enters into combina- 

 tion with sodium and with mercury at relatively low 

 temperatures, the mercury product being an unstable explosive 

 body : while there is spectroscopic evidence that similar 

 compounds with other metals, such as cadmium and 

 magnesium, are produced. 



When brought in contact with nitric oxide glowing nitrogen 

 reacts to form nitrogen peroxide, the reaction probably taking 

 place in accordance with the equation — 



2 NO + N = NO.>+N.2 

 It also effects the decomposition of acetylene and of chlorine 

 and bromine derivatives of hydrocarbons, with the liberation 

 of the halogen and formation of cyanogen. 



MINERAL CONSTITUENTS OF A DUSTY ATMOS- 

 PHERE. — A spectroscopic method of determining the nature of 



the dust in the atmosphere has been devised by Professor 

 Hartley {Proceedings of the Royal Society, 1911, LXXXV, 

 A, 2711. A series of photographs of spark spectra was taken 

 upon one plate, and compared with a similar series taken in 

 an atmosphere of hydrogen, the differences showing which of 

 the lines were due to impurities in the metal electrodes and 

 which to the dust in the atmosphere. 



It was found that the calcium and copper lines were intensi- 

 fied as the proportion of dust in the air increased, w-ith the 

 continuance of dry weather. With regard to the source of the 

 copper it is pomted out that this element is present in coal- 

 ash, and in the dust from the flues of chemical and gas 

 works, and that it is also introduced into the atmosphere by 

 the flashes of overhead cables : while the amount of calcium 

 is increased by tram and motor car traffic. In fact the 

 possibility of the copper or calcium in the atmosphere acting 

 as reagents, must be taken into account in all cases of 

 apparently spontaneous changes such as might have been 

 set up by traces of basic substances. They may also pro- 

 duce alterations in solutions that would not be affected by 

 exposure to a pure atmosphere. 



GEOLOGY. 



By G. W. Tyrrell. A.R.C.Sc. F.G.S. 



NEW THEORIES OF \ULCANISM. — R. A. Daly 

 iProc. Ainer. Acad, of Arts and Sciences. Vol. XLVII. 

 No. 3, 1911, pp. 45-122) bases a paper on "The Nature of 

 \'olcanic Action" on his well-known theory of abyssal 

 iniection. He believes th.at the world-wide granitic terrane 

 underlying the interrupted sedimentary shell is itself underlain 

 by a shell of eruptible basalt, which is the source and " heat- 

 bringer " of all igneous action. He points to the fact that all 

 the great lava-floods of the world are of basalt, and have 

 welled out from great fissures which are supposed to have 

 tapped this basaltic substratum, although it is not supposed 

 that simple openings extend to this depth. 



Other igneous rocks are believed to be due to the absorption 

 of the overlying acid shell, as abyssal injections of basalt, 

 caused by crustal deformation, work their way upwards by a 

 method known as " sloping." This involves the constant 

 wedging away of blocks from the roof of the resulting 

 batholith. and their solution in depth. The resulting mixed 

 magmas are called " sj-ntectics," and with or without 

 subsequent differentiation, are held to give rise to the known 

 variety of igneous rocks. 



Daly holds that vulcanism is a subsidiary effect of abyssal 

 intrusion. He distinguishes three phases of volcanic action — 

 fissure eruptions, in which lava rises with great rapidity through 

 relatively thin cracks in the crust : eruptions through local 

 foundering of the roof of a batholithic intrusion ; and central 

 eruptions of the common cone and crater type. Fissure 

 eruptions are well known, and beside the recent Iceland 

 examples, there are numerous others belonging to past ages. 

 The Yellowstone Park rhyolite is beHe\ed to be an example of 

 the second type of volcanic action. This huge mass of lava, 

 cut by canyons to a depth of six hundred meters without 

 revealing its base, lacking horizontal division-planes indicating 

 successive flows, is without parallel amongst lava-flows. Daly 

 believes that it passes gradually downwards into a batholithic 

 mass of granite, and is due to the foundering of part of the 

 roof of this batholith, whereby the molten rock was solidified 

 under surface conditions. 



Central eruptions are supposed to originate in a cupola-like 

 extension of the roof of a batholithic intrusion, where " stoping " 

 action would be intensified by a concentration of the hot 

 volatile magmatic fluids. On reaching the surface the 

 " cupola " would originate a volcanic focus, and a cone 

 would be formed. -At this stage the problem of the continu- 

 ance of the volcano becomes the problem of the continuance 

 of heat within the funnel. 



