July 19, 1894] 



NATURE 



283 



per cent, of the force of gravity upon it ; and electric forces 

 of not very dissimilar magnitudes must have acted on the 

 air electrified as it actually was in the non-spherical en- 

 closure used in our experiments. If natural air or cloud, 

 close to the ground or in the lower regions of the earth's 

 atmosphere, is ever, as in all probability it often is, electrified 

 to as great a degree of electric density as we have found it 

 within our experimental vat, the natural electrostatic force 

 in the atmosphere, due as it is, no doubt, to positive electricity 

 in very high regions, must exercise an important ponderomotive 

 force quite comparable in magnitude with that due to difference 

 of temperatures in different positions. 



It is interesting to remark that negatively electrified air over 

 negatively electrified ground, and with non-electrified air above 

 it, in an absolute calm, would be in unstable equilibrium ; and 

 the negatively electrified air would therefore rise, probably in 

 large masses, through the non-electrified air up to the higher 

 regions, where the positive electrification is supposed to reside. 

 Even with no stronger electrification than that which we have 

 had within our experimental vat, the moving forces would be 

 sufficient to produce instability comparable with that of air 

 warmed by the ground and rising through colder air above. 



§ 15. During a thunderstorm the electrification of air, or of 

 air and the watery spherules constituting cloud, need not be 

 enormously stronger than that found in our experiments. This 

 we see by considering that if a uniformly electrified girbe of a 

 metre diameter produces a difference of potential of 38 volts 

 between its surface and centre, a globe of a kilometre diameter, 

 electrified to the same electric density, reckoned according to 

 the total electricity in any small volume (electricity of air and 

 of spherules of water, if there are any in it), would produce a 

 difference of potential of 3S million volts between its surface 

 and centre. In a thunderstorm, flashes of lightning show us 

 differences of potentials of millions of volts, but not perhaps of 

 many times 38 million volts, between places of the atmosphere 

 distant from one another by half a kilometre. 



UNIVERSITY AND EDUCATIONAL 



INTELLIGENCE. 



The Council of the Owens College has, on the recommendation 



1 ihe Senate, made the following appointments to Fellowships 



111 the College :— Bishop Berkeley— Dr. A. W. Crossley in 



Chemistry, .\. H. Jameson in Engineering ; Honorary Research 



— Wilmot Holt, junr., in Chemistry. 



Mr. Andrew J. Herfiertson, of Edinburgh, has been 

 appointed Lecturer on Ceography at the Owens College, Man- 

 chester, in succession to Mr. Yule Oldham. 



tributes a paper to the lahrbtich, "On the Devonian strata of 

 Graz," in which he proves that the " Coral limestone " and the 

 " Calceola horizon " immediately above it are the uppermost 

 bed of the Lower Devonian series. The age of the palaeozoic 

 strata of Graz ranges, according to Dr. Penecke, from the 

 oldest Silurian to the youngest Devonian, and may possibly 

 include a part of the Lower Coal Measures. — The monograph of 

 the RaibI strata, by Baron von Wufirmann, marks a consider- 

 able advance in our knowledge of Alpine Trias. The author's 

 previous papers on the RaibI fauna in North and South Tyrol, 

 have paved the way for this general paper. All the RaibI lacies 

 known in the Alps are described, the species contained in 

 them reviewed, the indications of the geographical conditions 

 discussed, and comparative references made to extra-.-Mpine 

 seas in the same period. The subject is one of the most com- 

 plex, but its treatment is searching, concise, and exhaustive. 

 We note, almost with relief, the entire absence of the speculative 

 method and wordy argument too frequently seen of late in 

 matters concerning the Alps. 



Bd xliv. Heft 2, June 1804. — "On the newer literature of the 

 Alpine Trias," by Dr. A. Bittner. The personal and polemical 

 tone of this paper renders it somewhat remarkable. By way of 

 reviewing the terminology and literature of the Alpine Trias, Dr. 

 Bittner exposes scathingly the fashion of new name-giving on 

 insufficient grounds, the prejudice and obstinacy with which a 

 name once given is apt to be retained, and the danger to 

 science of subsequent attempts to modify the original meaning 

 of a name, and prop a deservedly falling fabric. The writings 

 of Mojsisovics are those which specially come under the whip. 

 We are told, for example, that in studying " the Cephalopoda 

 of the Hallstadt Limestone," one of the greatest works of 

 Mojsisovics, we must read everywhere — instead of Medi- 

 terranean Trias, Alpine Trias ; instead of Juvavic horizon, 

 Noric horizon ; instead of Noric horizon, Ladinian horizon ; 

 the author of the work himself having entirely departed from 

 the geological conceplions for which the names were creaied ! 

 Dr. Bittner's paper is, to say the least, breezy ; but, on the 

 principle of the old proverb, " It's an ill wind, &c.," there is no 

 doubt it will have a healthful effect in blowing away some of 

 the cobwebs of tradition Irom a study which nature had already 

 made so difficult and so fascinating. 



SCIENTIFIC SERIALS. 



Amnican Journal of Matlumatics, vol. xvi. 3. (Baltimore : 

 July 1894.) — A class of uniform transcendental functions, by 

 Dr. T. Craig (pp. 207-220), gives another mode of forming a 

 certain transcendental function first introduced by M. Picard 

 (Comptts Reudus, 187S), and which does not seem to have been 

 subsequently discussed. M. G. Humbert (pp. 221-253), writing 

 "Sur les surfaces de Kummerelliptiques," after mentioning that 

 Cayley's lelrahedroid is a particular case of a Kummer surface 

 with six double points, applies himself to the problem of 

 determining whether any other of these surfaces possess similar 

 properties. — Mr. Basset contributes a memoir on the deforma- 

 tion of thin elastic plates and shells (pp. 254-290). The 

 origin of the investigation appears to be the dissatisfaction 

 Mr. Basset has felt with Mr. Love's treatment of the theories of 

 thin plates, shells, and wires in the second volume of his book 

 on " Elasticity." 



lahrbuch der k. t. secht;. Rtichsanslalt ]Vien. Bd. xliii. Heft 

 3and4, March 1894.— AllhoughGraz is one of the few localities 

 in the Central Alps in which palieozoic strata are present contain- 

 ing good fossils, the exact age of these strata and their parallelism 

 with the Silurian and Devonian strata of extra-Alpine regions 

 have remained uncertain. The richly fossiliferous Coral-limestone 

 of the Graz succession was determined as mid-Devonian by Suess, 

 Stache, and others. Iloernes, on the other hand, thought it 

 Lower Devonian. Now, for the first time, the Corals have been 

 made the subject of a detailed study.— Dr. K. A. Penecke con- 



NO. 1290, VOL. 50J 



SOCIETIES AND ACADEMIES, 



London. 

 Royal Society, May 10. — "The Composition of .\t- 

 mospheres which Extinguish Flame." By Dr. Frank Clowes, 

 Professor of Chemistry, University College, Nottingham. 



The statements usually published, as to the proportion of 

 carbon dioxide in air necessary to extinguish a candle flame, 

 vary widely. The present investigation was undertaken with 

 the object of fixing the minimum proportion of carbon dioxide 

 and of nitrogen gas, which, when mingled with air, will ex- 

 tinguish flame ; anil with the further object of ascertaining also 

 the minimum proportion of each of these gases, which is 

 necessary to extinguish the flames of different combustible 

 substances, including those of certain gases. 



The method of experimenting, which was devised, prevented 

 the introduction of errors arising from the incomplete mixture 

 of the gas with the air, from the solubility of carbon dioxide in 

 water, and from the effect of carbonic dioxide produced fronj 

 the flame during its combustion. The proportions of gas and 

 air in the mixtuies used were checked by analysis and were 

 shown to be accurate, and duplicate experiments agteed in 

 their results closely. 



A preliminary series of experiments proved that, within the 

 wide limits selected, the extinctive proportion of carbon dioxide 

 was independent of the j;;i.- of the flame of any particular 

 combustible which was introduced into the mixture. 



An extended series of experiments was then made to ascertain 

 the minimum extinctive proportion of carbon dioxide for flames 

 of very various description. The results arrived at showed 

 that the flames of very different combustibles which were burnt 

 from wicks, required a strikingly similar proportion of carbon 

 dioxide in the air for their extinction. Thus the percentage of 

 carbon dioxide necessary for the extinction of the flames of the 

 following combustibles were: for absolute alcohol, 14; for 

 methylated alcohol, 13 ; for paraffin oil, 15 ; for mixed colza and 

 petroleum, 16 ; and lor a candle, 14. 



