A L GUST I 8, I 910] 



NATURE 



207 



Royds rarely rises above freezing-point, and there is 

 no vegetation higher than mosses. It is therefore 

 surprising to hear of an abundant microscopic fauna 

 and flora. Mr. Murray's experience stood him in good 

 stead, for he made much of a very unpromising centre 

 of operations. "The kinds of animals which are 

 usually to be found among mosses have at Cape 

 Royds a shelter of another sort, which, judging from 

 their numbers, appears to suit them better. This is 

 furnished by the foliaceous vegetation which grows so 

 abundantly in the lakes and ponds." Thus Mr. 

 Murray reports : — " I have never anywhere seen 

 bdelloid rotifers so plentiful as are the two dominant 

 species at Cape Royds (Philodina grcgaria and 

 Adincta graiidis). . . . The water-bears are of only a 

 few kinds, but one of them {Macrobiotus arcticus) is 

 extremely abundant. There are nematode worms of 

 two or more kinds, mites of several kinds, and two 

 Crustacea belonging to the Entomostraca. The ciliate 

 infusoria are very numerous, there are a good many 

 flagellata, but only two rhizopods were observed." 

 Numerous microphotographs were taken under dis- 

 advantageous conditions, and some of these are 

 printed — showing not only rotifers, water-bears, and 

 the like, but seme other creatures whicn the editor has 

 wisely refrained from naming. 



Some sixteen species of rotifers were distinguished, 

 representing all the orders, though mostly bdelloids. 

 Ihis is the first definite record of rotifers within the 

 Antarctic Circle, and five of the bd>:lloids are new 

 species, llie most interesting facts are those regard- 

 ing the toughness of the rotifer constitution. Thus 

 Philodina gregaria n. sp. is normally frozen in the 

 ice of the lakes for the greater part of the year, and 

 revives at any time that the ice is thawed. It may be 

 alternately thawed and re-frozen at weekly intervals 

 for several months. In England it was subjected to a 

 temperature of —78° C. for many hours, by Mr. 

 J. H. Priestley, of Bristol, and survived. Of Adincta 

 ^randis n. sp., which survived the lowest temperatures 

 experienced at Cape Royds ( — 40'^ F.), and repeated 

 freezing and thawing, and immersion for a month in 

 sea-water, it is further recorded that "a proportion of 

 them lived after the bottle containing them (in the 

 dry condition) was immersed in boiling water for a 

 short time. It was one of the rotifers which was to 

 be seen alive and active in London in September, 1909, 

 after being dry for about a year, and spending some 

 months in tropical and sub-tropical climates." This 

 toughness of constitution is interesting in several ways ; 

 ^.g., in showing that these .\ntarctic rotifers can stand 

 very adverse circumstances in the course of dispersal. 

 Another point of interest concerning the rotifers is that 

 the two dominant species, named above, are viviparous, 

 wliich seems therefore the mode of reproduction best 

 adapted to secure success in the struggle of existence 

 under the severe conditions at Cape Royds. M. Jules 

 Cardot reports on four mosses ; the rest of the report 

 is due to Mr. Murray, to whom we offer congratula- 

 tions. 



(3) From a third .Antarctic expedition, the Belgica 

 ■(1897-9), some additional reports have been recently 

 received. Thus Dr. H. J. Hansen, who has done such 

 •good work among the Crustacea, describes some new 

 schizopods and cumacea. He indicates, as other 

 authorities on crustaceans have done, that the familiar 

 title schizopods will have to go, and that the orders of 

 Euphausiacea and Mysidacea, which it includes, are 

 far from closelv related to each other. In regard to 

 Euphausia superba he notes that it is the staple food 

 supply of seals, such a's Lobodon carcinopliaga, and 

 that it seems to live everywhere in the .Antarctic Ocean. 

 A. Pelikan gives a petrographical account of diorites, 



NO. 2129, VOL. 84] 



gabbros, porphyrites, and other types of rock collected 

 by the expedition. Prof. A. Gilkinet reports on a few 

 fossil plants from Magellan ; Fagus, Nothofagus, 

 Myrtiphyllum, Saxegothopsis, which seem to be of 

 relatively recent age, and bear a close resemblance to 

 members of the present-day flora of that region. H, 

 van Heurck reports on the diatoms and adds to the 

 value of his work by a survey of polar diatoms in 

 general. Henryk Arctowski gives a beautifully illus- 

 trated account of his personal observations on the 

 different kinds of ice and their transiormaticjns. These 

 observations are all the more interesting since very 

 little was known of southern ice before the vovage of 

 the Belgica. As the author indicates, a good deal has 

 been done since. 



ATOMIC WEIGHTS.'^ 



]~^ R. CLARKE continues to put all chemists 

 *-^ under an obligation to him by reason of the 

 zeal and care with which he collects and disseminates 

 information concerning the most important of all 

 chemical constants — the atomic weights of the 

 elements. In the volume before us — the third edition 

 of a work with which his name is inseparably asso- 

 ciated — he has brought to a focus all contemporary 

 knowledge on the subject, discussing, digesting, and 

 weighing the experimental evidence with the same 

 lucidity, completeness, and impartiality which have 

 characterised his previous publications. 



It is interesting and instructive to compare the 

 present issue with the original one of 18S2. The num- 

 ber of the chemical elements has not greatly increased 

 during the last thirtv years. Even including the inert 

 gases of the atmosphere and such of the radio-active 

 elements of which the individuality may be said to 

 be established, the increase is not more than about 

 a dozen, and such values of their atomic weights as 

 we possess are only of the order of first approxima- 

 tions. The most significant feature of the difference 

 between the two issues is seen rather in the far higher 

 standard of accuracy' which is now required in such 

 estimations. It is absolutely useless nowadays for 

 anybody to engage in such determinations who is not 

 prepared to impose upon himself the most rigorous 

 checks, the most scrupulous attention to detail, ana 

 an inflexible determination to put forward no result 

 that will not stand the severest scrutiny. 



Atomic weights to-day are reouired for other pur- 

 poses than chemical arithmetic, and comparatively rough 

 approximations serve for the greater number of the 

 operations of quantitative analvsis. The errors due 

 to manipulation, and to the use of methods faulty in 

 principle, are, as a rule, far larger than those due to 

 the employment of incorrect values for the atomic 

 weights. Instances, indeed, might be quoted where 

 it is apparently necessary to adopt a confessedly in- 

 accurate value for an atomic weight in order to com- 

 pensate for the error due to an imperfect method of 

 quantitative estimation. Certain large trade opera- 

 tions could not be equitably arranged on any other 

 basis. This, of course, does not concern the chemist 

 as a man of science, and is certainly no argument for 

 the retention of an inaccurate constant in our tables 



1 (i) The Constants of Nature. Part v., A Recalculation of the 

 Atomic Weiqhts. Third Edition. Revised and Enlarged. By Frank 

 Wigglesworth Clarke. Pp. iv+548. (Washington : Smithsonian Institu- 



(2) Determinations of Atomic Weights. Further Investigation con- 

 cerning the Atomic Weights of Silver, Lithium and Chlorine. By Theodore 

 W. Richards and Hobart Hurd Willard. 



The Harvard Determinations of Atomic Weights between 1870 and 

 191". By Theodore W. Richards. 



Methods used in Precise Chemical Investigation. By Theodore W. 

 Richards. Pp. iv-t-113. (Washington : Carnegie Institution, 1910.) 



