February 21, 1901] 



MATURE 



405 



mammalian remains from the Upper Tertiary of Texas, and 

 several truck-loads of dinosaurian bones from the Jurassic of 

 Wyoming and the Cretaceous of Dakota have reached the 

 Museum as the result of last season's work. The dinosaurian 

 remains include the skeletons of one large carnivorous form and 

 of another more nearly allied to the iguanodon. In the same 

 journal will be found an account of the collections in the geo- 

 logical department of the Museum and the manner in which 

 they were ^acquired. The first important acquisition was the 

 Holmes collection from the Tertiary of South Carolina ; this 

 was followed, in 1875, by the James Hall collection, which at 

 once placed the Museum in the foremost position among 

 American institutions in regard to Palaeozoic fossils. 



Prof. Penck contributes a valuable paper to the Zeitschrift 

 of the Berlin Gesellschaft fiir Erdkunde, on the glacial pheno- 

 mena of Australia. The evidences of glacial action in different 

 parts of Australia during permo-carboniferous times are dis- 

 cussed in detail, and brought into relation with traces of simul- 

 taneous action in India and South Africa ; and it is shown that, 

 apart from other difficulties, the hypothesis of a shifting of the 

 South Pole to a central point (on the tropic of Capricorn in 

 long. 86° E. ) does not satisfactorily account for the geological 

 facts. It is next pointed out that the appearances ascribed to 

 ice action present in each case certain features not characteristic 

 of ordinary glacial deposits — the deposits are stratified, and the 

 pebbles are facetted in the manner first described by Wynne. 

 Further, the Gondwana beds, always closely associated with 

 these boulder deposits, have lately been found in the Argentine 

 Republic. Prof. Penck compares the bedding and facetting with 

 conditions induced by pressure observed in the Nagelfluh and 

 in certain localities near Vienna, and concludes that while many 

 indications certainly point to glacial action, these special points 

 must be fully investigated before the formidable problem of 

 accounting for the existence of glacial conditions over such an 

 enormous area can be attacked. The second part of the paper 

 summarises present knowledge of the quaternary glacial, or 

 glacier, period in Australia and New Zealand, and compares the 

 probable elevation of the snow-line in Australia and western 

 Europe in quaternary and modern times. 



Messrs. J. J. Griffin and Sons have just introduced a 

 new form of balance which should find a place on many lecture 

 tables. The instrument is large enough to be seen clearly by a 

 large class, and it can be manipulated by the lecturer without 

 standing in front of it. The sensitiveness, rate of swing, length 

 of arm and other characteristics can be altered so as to illustrate 

 the principles of construction of a balance. 



A PAPER by Messrs. K. A. Hoffman and E. Strauss on 

 "radioactive lead" appears in the current number of the 

 Berichte. This material is extracted from various minerals such 

 as pitchblende, cleveite, broggerite, copperuranite, samarskite 

 and euxenite, and resembles lead in being precipitated from its 

 acid solution by sulphuretted hydrogen, in forming a sulphate 

 insoluble in dilute sulphuric acid, and in having a yellow iodide. 

 It differs from lead in the fact that it acts upon a photographic 

 plate in the dark ; it possesses a characteristic violet line in its 

 spark spectrum, and its equivalent is markedly different, being 

 65 05 as against 517 for lead. The authors regard their results 

 as being due to the presence of an element of an atomic weight 

 of over 260, probably either divalent or tetravalent. 



In a recent contribution to the Proceedings ol the American 

 Academy of Arts and Sciences, Prof. Richards, of Harvard, 

 expresses the opinion that ihe formal sanction of an inter- 

 national table of atomic weights is only a matter of a short 

 time. The opinion elicited by the Commission of the German 

 Chemical Society is overwhelmingly in favour of = i6'00 



NO. 1634, VOL. 63] 



(H = i"oi) as against H=i (0=I5"88), though some eminent 

 authorities would adhere to the old standard. The second 

 question put by the German Commission, as to whether the last 

 figure set down in an atomic weight should be correct to within 

 half a unit, is also answered in the affirmative by a large majority. 

 From this consensus of opinion Prof. Richards is a dissentient, 

 and he explains his position by reference to the case of nitrogen. 

 The International Committee constituted through the German 

 Chemical Society appears already to have made its decision, 

 for in the first number of the Berichte for the present year 

 there are inserted two tables of atomic weights, one of which 

 is headed "Internationale Atomgewichte. " In this the basis 

 is O = i6'oo(H = I •008), and the numbers given are accurate 

 to one unit in the last place. The second table issued with the 

 Berichte is of " Dldaktische Atomgewichte " to the basis 

 H = I "00(0= 1 5 '88). It is obviously intended to meet the 

 objections of teachers who foresaw difficulties in having to 

 explain the use of 16 as the basis of a numerical system for 

 atomic weights and densities. Opinions will differ as to the 

 wisdom of having two tables current, but in any case they need 

 not both be adopted by the same person. It would be hard 

 for a teacher to have to remember that in the class-room S was 

 31 '83, whilst in the laboratory it was 32 "06. It is probable 

 that most didactic requirements will be satisfied with S = 32. 



The additions to the Zoological Society's Gardens during the 

 past week include a Common Guinea Fowl {Ntimida meleagris) 

 from Morocco, presented by Mr. G. E. Veroutsos ; fourteen 

 Tree Frogs (f^yla, sp. inc.) from Barbadoes, a Capuchin (Cedus, 

 sp. inc.) from South America, a Black-handed Spider Monkey 

 {Ateles geoffroyi) from Central America, two Blood-rumped 

 Parrakeets {Psepholus koeniatonottis) from Australia, deposited; 

 an August Amazon [Chrysotis augusta) from Dominica, four 

 Banded Grass Finches {Poephila c inct a) ixom Queensland, two 

 Arizona Heloderms {Helodernia suspectum) from Arizona,. 

 U.S.A., purchased. 



OUR ASTRONOMICAL COLUMN, 



Reduction of Observations of Eros. — In anticipation of 

 the conclusion of the work on the planet Eros during the recent 

 opposition. Prof. G. C. Comstock, of Washburn Observatory, 

 U.S.A., contributes a note to the Astronomical Jottrnal, No. 

 490, on the limits available in the necessary reductions. The 

 question of reducing micrometer measures depends on the 

 degree of accuracy with which it may be assumed that the mean 

 of a number of settings represents the positions of the planet 

 and comparison stars at the mean of the observed times. The 

 problem is discussed with respect to three independent sources 

 of changes in the observed coordinates. 



(rt) Geocentric motion. — General result is that if a set of 

 measures does not extend over a period greater than one hour, 

 the planet's motion may be treated as uniform, with a probable 

 error of ± o"'oi. 



(b) Parallax, which changes with the observer owing to the 

 diurnal motion. In this case the interval allowable is less than 

 half an hour. 



{c) Differential refraction, varying with the time of observa- 

 tion. For this element a table is given showing the correction 

 introduced for varying zenith-distances. 



Constant of Aberration. — The results of zenith-telescope 

 observations of latitude at the Flower Observatory, University 

 of Pennsylvania, are given by Mr. C. L. Doolittle in the Astro- 

 nomical Journal (No. 490). 



The correction to Struve's aberration constant was determined 

 from these observations and applied to the final reductions. 

 The following values of the constant have hitherto been 

 derived : — 



