November 25, 1915I 



NATURE 



353 



, There is a companion shower, often rather strikingly 

 1 visible at the same time, and its radiant point is 

 about 10 degrees east of the chief system. It appa- 

 rently shows a similar displacement to the eastwards 

 at the rate of about i degree per day. 



These showers from Gemini are sometimes extremely 

 active, and on the night of the maximum, about 

 December ii, furnish 20 or 30 meteors per hour for 

 one observer. They have swift flights, not often with 

 conspicuous trains or streaks, and are not recorded 

 so easily and accurately as the meteors from Perseus 

 in August or those from Leo in November. 



Comet 19 15^ Mellisii.— Orbital elements for this 

 comet have been calculated by Messrs. S. Einarsson 

 and Alter, of the Berkeley Astronomical Department 

 (Lick Observatory Bulletin, No. 273), from three 

 observations made by Aitken on September 20, 21, 

 and 23 : — 



T= 191; Oct. 13-3959 <^-M.T. 



, .0(5 / ^ /'N 



o) = 1 1 8 50 30 ^ 

 ft= 77^42' 52'7 

 i = Sf 32' 41" J 



1915-0 



t ■■ 

 log q =964669 



Elements deduced by Messrs. Braae and Fischer- 

 Petersen were given in this column for October 14. 

 It is pointed out that the orbit plane is nearly the 

 same as that of comet 19 15, also discovered by Mellish. 

 In the current number of the Observatory Dr. Crom- 

 melin states that the elements show a distant re- 

 semblance to those of the comet of 1402. 



Visibility of Mercury. — The last W. elongation 

 (18° 49') of this planet occurred on November 7, and 

 although only two-thirds of the jx)ssible maximum, 

 the planet was seen by Mr. H. E. Goodson from 

 the Hill Observatory', Salcombe Regis, ten days later 

 on the morning of November 17, just before 6.15 a.m., 

 attracting attention as a conspicuous naked-eye object, 

 less than 1° above the eastern sky-line in a moderately 

 bright dawn. 



The Light-curve of RZ Cassiopeia. — A number 

 nf minima of this important circumpolar short-period 

 • liipse variable have been followed by Sig. E. Pad, at 

 ; he Royal Observatory of Catania {Mem. Soc. Spett. 

 Ital., September). The measures were made by means 

 of a Topfer wedge photometer attached to a Cooke 

 telescope of 15-cm. aperture. The mean light-curve 

 is based on 2274 measures made during eight minima 

 since last July, and the magnitude ranges from 

 5-9-7-8 in 2h. 45m. 



RECENT SCIENTIFIC WORK IN ITALY. 



SINCE the outbreak of war in August, 19 14, up to 

 the end of May last, when Italy entered into 

 the struggle, the output of scientific work in Italy 

 seems to have suffered but little from the general 

 upheaval which has in other countries so largely dis- 

 organised scientific effort. The Atti of the Royal 

 Academy of the Lincei, which may be taken as re- 

 presentative of scientific work in general, embracing 

 as it does all the different branches, shows during 

 this period very little falling off from previous years 

 cither in the number or quality of the papers pub- 

 lished. This may be seen from a brief review of the 

 contributions of general interest published in vol. 

 xxiii., part ii., and vol. xxiv., part i., which cover this 

 period. 



Prof. C. Acqua (vol. xxiii., ii., p. 78) has an 

 interesting paper on the artificial absorption of liquids 

 by the aerial parts of plants, in which a description is 

 given of the striking effects produced bv allowing 

 living plants to absorb nutritive solutions through the 



NO. 2404, VOL. 96] 



leaves or cut branches. Plants which ordinarily die 

 down in the autumn were in this way kept in leaf 

 throughout the winter by the absorption of saccharose, 

 whilst in other cases plants placed in unsatisfactory 

 conditions of growth, which ordinarily would cause 

 rapid fading, were revived by administering sugar 

 solutions through the leaves or stalks. 



Dr. V. Paolini and R. Lomonaco (vol, xxiii., ii., 

 123) show that the green essential oil obtained from 

 Italian-grown wormwood (Artemisia absinthium) con- 

 tains about 10 per cent, of a mixture of a- and 

 ^-thujones, 48 per cent, of thujylic alcohol, either free 

 or in the form of acetic, isovaleric, and palmitic 

 esters, and smaller proportions of phellandrene, 

 cadincno and a blue oil of undetermined composition. 



From a study of the effect of very dilute acids on 

 the germination of oats {Avena sativa), Prof. R. 

 Pirotta (vol. xxiii., ii., 166) concludes that the anion 

 and kation of the acid have distinct effects, both 

 chemical and biological, on the plant ; the hydrogen 

 acts on the root, and the reaction is localised therein, 

 whilst the effect of the anion is localised on the grow- 

 ing points. From a similar study made by Dr. F. 

 Plate on the effect of the chlorides of the alkjili metals 

 on germination, it is seen that the chlorides produce 

 very different effects from the corresponding nitrates, 

 the difference being due to the presence of a different 

 anion. 



In two papers on the formation of hydrocyanic acid 

 in plants. Prof. C. Ravenna (vol. xxiii., ii., pp. 222 

 and 302) points out that in the estimation of small 

 quantities of hydrogen cyanide in such cases, it is 

 preferable to use potassium chromate as an indicator 

 in titrating with silver nitrate solution rather than to 

 employ Liebig's or Deniges's method. It is shown by 

 a number of experiments on Phaseolus liinatus tha't 

 this plant on germination at first produces hydrogen 

 cyanide in increasing quantities, but that after a time 

 the amount falls off. This plant, therefore, is no 

 exception to the rule formerly established by the 

 author with regard to the course of formation of 

 hydrogen cyanide by cyanogenetic plants. 



Dr. A. Clementi (vol. xxiii., ii., 517 and 612) 

 describes a new method of determining the action of 

 arginase, based on the quantitative estimation, by 

 merms of the formaldehyde process, of the new amino- 

 group formed by hydrolysis of the arginine to urea 

 and ornithine. . Arginase is shown to be present, not 

 only in the press juice of the liver of mammals, but 

 also in aqueous extracts of these. In a later paper 

 Dr. Clementi (vol. xxiv., i., 352) shows that Sorensen's 

 titration process in presence of formaldehyde can be 

 applied to mono-substituted amino-acids, such as 

 sarcosine ; as slight hydrolysis occurs in such rases, 

 it is, however, necessary, in order that the results 

 correspond with the whole of the acid present, that 

 alkali should be added up to the point when an intense 

 red coloration is produced with phenolphthalein. 



Dr. Eva Mameli and Prof. G. PoUacci (vol. xxiv., 

 i., 966) deal with the question of the direct assimila- 

 tion of atmospheric nitrogen by plants. As the result 

 of numerous analyses conducted under a system of 

 rigorous control, it is concluded that the faculty of 

 assimilating nitrogen directly from the air is far more 

 widely distributed among plants than has hitherto 

 been admitted. Nearly all chlorophyll-containing 

 plants, from algae to phanerogams, can, under special 

 conditions, make use with greater or less activity of 

 the atmospheric nitrogen. This property is most 

 strongly marked in the Hydroptcridae, such as AzoUa 

 carolinianum and Salvinia iiatans, and in Lemna 

 major and L. minor, but phanerogams such as 

 Cucurbita pepo, Acer negundo, and Polygonum 

 fagopyrum also possess it. 



