February 23, 1922} 



NATURE 



.251 



lonosporous mycelia in the genus Coprinus, and a 

 lote by Mr, Collet describing viability in Fumago 

 igans after sixty-seven years' preservation as a 

 srbarium sf)ecimen. The issue is well produced and 

 lustrated by five plates, two of which are beautifully 

 >loured. 



SiLiciFiED Plant Remains.— The Middle or Lower 

 Bvonian flora discovered by Dr. Mackie at Rhynie, 

 Aberdeenshire, was generally reviewed by Prof. 

 O. Bower in 1920 (Nature, vol. 105, pp. 681 and 

 ri2). Dr. Kidston and Dr. W. H. Lang (Trans. Roy. 

 Edin., vol. 52, pt. 4, 1921) now describe the 

 lallophytes occurring in the remarkable silicified 

 it-bed, and discuss the conditions of accumulation, 

 le sequence is due to continued growth on a land- 

 irface that was at times submerged in lake-waters 

 impregnated with silica. A volcanic source is sug- 

 gested for the silica, and it is pointed out that the 

 growth of cyanophaceae and bacteria in modern hot 

 springs is known to promote a deposition of colloidal 

 silica. We may note that Prof. W. N. Benson (Proc. 

 Linn. Soc., New South Wales, vol. 45, p. 315, 1920) 

 refers the silicification of remains of gymnosperms in 

 Carboniferous beds on Mount Cobla, New South 

 Wales, to contemporaneous hydrothermal solutions 

 associated with the deposition of keratophyric tuflfs. 

 In view of climatic changes in the past, the possibility 

 of the spread of siliceous waters derived from laterisa- 

 tion must not, of course, be overlooked. 



Austrauan Meteorology. — Meteorological statistics 

 for the Australian Colony of Victoria have recently 

 been published, based on all the available records ob- 

 tained at 1046 official stations from January, 1856, to 

 December, 1907. They have been prepared under the 

 direction of Mr. Pietro Baracchi, Government Astro- 

 nomer from 1895 to 1915. Observations were 

 commenced at Melbourne in 1840 and continued 

 until 185 1, when, in consequence of Government 

 changes, there seems to have beer a break for about 

 four years. From 1855 observations were made at 

 Melbourne and at some twenty stations in different 

 districts of the Colony. All observations were con- 

 trolled by the authorities at Melbourne Observatory 

 until 1907, when the meteorological duties were taken 

 nver bv the Government of the Commonwealth of 

 \ustralia under the control of ihe Commonwealth 

 Meteorologist, Mr. H. A. Hunt. The observations 

 included in the volume received are a summary of 

 results to 1907, when the responsibility of Melbourne 

 Observatory ceased. This volume of the early Aus- 

 tralian weather observations is of great value as 

 affording data for seasonal changes and possibly 

 showing meteorological irregularities of interest in 

 ronnrction with more recent observations. A detailed 

 history is given of the development of the system of 

 observing and showing the requirements and value 

 of meteorological observations, especiallv a thorough 

 knowledge of rainfall distribution. Many details 

 Jven in the introduction are of extreme value, and 

 how most thorough supervision and great alertness 

 ^ to the utility of special observations. At Melbourne 

 'hservations are given for a period of fifty vears. The 

 mean and extreme values for the several elements and 

 for the different regions of observation are of high 

 scientific value. 



Standard Cells of Low Voltage. — In the issue 

 for November, 192 1, of the Proceedings of the 

 Physico-Mathematical Society of Japan Mr. J. Obata 

 describes the investigation he has carried out on the 

 possibilitv of constructing standard cells of low 

 voltage for testing purposes. Nine types of cell have 



NO. 2730, VOL. 109] 



been studied, in all of which cadmium or cadmium 

 amalgam formed the negative, and cadmium or lead 

 amalgam the positive pole. The electrolytes were 

 solutions of lead or cadmium sulphate, chloride, 

 bromide, or iodide, and the cells were given the H 

 form. The two cells which proved most suitable for 

 standards were the cadmium amalgam /cadmium 

 iodide/lead iodide/lead amalgam cell with an electro- 

 motive force at 20° C. of 009838 volt and a tem- 

 perature coefficient of 000024 volt per degree, and a 

 cadmium amalgam (10 per cent.)/cadmium sulphate 

 solution /cadmium amalgam (dilute) cell with an 

 electromotive force of about o-oi volt and a tem- 

 perature coefficient of about 00004, according to the 

 strength of the dilute gmalgam. 



Magnesium in Organic Chemistry. — Mr. H. Hep- 

 worth describes in the issue of the Journal of the 

 Society of Chemical Industry for January 16 the 

 recent applications of magnesium in organic chemistry. 

 The "Grignard reaction," since its discovery in 1900, 

 has found numerous applications in organic synthesis, 

 and this paper is an interesting rdsumd of much 

 recent work. The following examples will serve to 

 illustrate the new lines of research made possible by 

 the use of magnesium compounds. Cyciopentamethyl- 

 stannines, in which the ring contains an atom of tin 

 replacing carbon, have been obtained. Tin diaryl- 

 compounds exhibit an intense colour. Lead tetra- 

 alkyls, lead triaryls, apparently analogous to tri- 

 phenylmethyl, and mixed tin and lead compounds 

 have been prepared, and I-phenylchloroacetic acid is 

 converted by magnesium phenyl bromide into d-di- 

 phenylsuccinic acid. The use of ether in preparing the 

 Grignard reagent is not essential, but the early view 

 that an additive compound was formed seems to have 

 received confirmation by the isolation of a crystalline 

 compound, 2(C,H,),,PO,CH3MgI, when tribenzyl 

 phosphine oxide is used instead of ether, and of 

 crystalline (C5H,,).0,MgCH3l with amyl ether. In- 

 stead of the oxonium structure for such compounds, 

 a formula in which magnesium is the central atom 

 with co-ordination number 4 has been proposed, the 

 ether being attacked by subsidiary valencies. 



Vibrations of Vehicles. — According to an article 

 by M. A. Boyer-Guillon in the November issue 

 of the Bulletin of the Soci^t^ d'encouragement 

 pour rindustrie nationale, ^ the Auclair and 

 Boyer-Guillon accelerometer is to be used in 

 the near future in a detailed study of the oscilla- 

 tions, shocks, or vibrations to which the rolling 

 stock of the French railways is subjected. The Auto- 

 mobile Club of France and the Society of Architects 

 propose also to use it in a study of the vibrations 

 of buildings. The instrument has already led to the 

 solution of problems connected with the failure of 

 machines apparently well designed for the stresses 

 they were expected to withstand. In most cases it has 

 shown that the accelerations to which parts of the 

 machines were subjected were for in excess of those 

 contemplated. Used on autocars in Paris streets it 

 gives the vertical accelerations on irregular wood and 

 on good stone pavements as between 6 and 7 metres 

 per sec. per sec. at a speed of 27 km. per hour. The 

 instrument itself consists of a heavy mass held up^ by 

 springs attached to the ends of tods which project 

 radially from it. The springs are of graduated 

 strengths, and each holds the rod to which it is 

 attached against a stop with which it makes elec- 

 trical contact until the down acceleration breaks the 

 contact, and the break is registered on the revolving 

 drum of a chronograph. 



