May 30, 1889] 



NA TURE 



117 



nith Africa (with four plates), including the Gamopetalous 

 Dicotyledons, by Dr. Engler, &c. — The Piperacex collected by 

 Lehmann in Guatemala, Costarica, Columbia, and Ecuador, 

 described by Casimir de Candolle. — A new plant belonging to the 

 OlacineK {Tetrastylii/ium Engleri, Schwacke), by W. Schwacke. 

 — An anatomical study of Scirpus and allied genera (with one 

 plate), and a key for distinguishing them on anatomical grounds, 

 by Dr. Ed. Palla. — On some mistaken, or little-known Rubiacea; 

 of South America, by Karl Schumann. — On the flora of Green- 

 land, by Eug. Warming. Including interesting descripti ins of the 

 general appearance of the vegetation, as well as the habit of certain 

 species, with a discussion of the origin and relations of the flora. 

 The author concludes that Greenland is not a European province, 

 from the point of view of botanical geography, but has nearer 

 relations to America. —Contributions to the comparative 

 anatomy of the AristoJochiacea; (with tliree plates), by Dr. H. 

 Solereder. A comprehensive investigation of the structure of 

 both vegetative and reproductive organs. — The volume also 

 includes the usual personal notices, and abstracts of current 

 literature, together with a list of works recently published on 

 geographical and descriptive botany. 



Journal of the Russian Chemical and Physical Society, vol. 

 xxi. No I.— On hexabromtetramethylene, by A. Sabaneyeff. 

 — On the heat of solution of lithium bromide. It is equal 

 to 11*351, and thus occupies an intermediate position between 

 those of LiCl (8-440) and Lil (14-886).— On the action of 

 ethyl iodide and zinc upon paraldehyde, by W. Wedensky. — 

 On the oxidation of erucic and ricinoleic acids by means of 

 permanganate of potassium, by L. Urvantzoff and W. Dieff. — 

 On the formation of cane-sugar from starch in plants, by F, 

 Selivanoff. It was observed in tubercles of potatoes, — Notes by 

 MM. MoltchanoflsUy, Alcxeyeff", and Kondakofif.— Theoretical 

 researches into the motion of water in the subsoil, by N. 

 Joukovsky. The author concludes from his mathematical inquiry 

 and some experiments that the law of Darcy remains satisfactory 

 if the secondary causes are also taken into con-ideralion and the 

 results are not extended to great distances from the well. As to 

 the corrections of Darcy 's law proposed by Kriiber and Smreker, 

 they do not yet correspond to all facts noticed during pumpings. 

 — Note by W. Rosenberg on cyclonic movements. 



No. 2. — Yearly reports of the Society. — Notes on primary, 

 secondary, and tertiary nitro-compounds, by J. Bevad. — On the 

 general law of contraction which takes place during the forma- 

 tion of solutions of salts, by A.Gueritch ; second paper, containing 

 data relative to H^.SOj and HCN.— On the action of chlorides 

 and hydrochloric acid upon the photochemical decomposition 

 of chlorine-water, by E. Klimenko and G. Pecatoros. They 

 slacken the decomposition. — On the vapour density of ethyl 

 isocyanurate at various temperatures, by S. Krapivine and N. 

 Zelinsky. — On the dilatation of solutions of salts, by N. 

 Tchernay ; third paper, containing tables relative to nine different 

 nitrates. — Note on electrical phenomena due to actinic influences, 

 by J. Borgmann. 



In the Amei-ican Meteorological Jotirnal for March, Mr. A. 

 L. Rotch continues his interesting articles on the meteorological 

 services in Europe, dealing in this number with the Paris and 

 Montsouris Observatories. The interest of the Paris Observa- 

 tory, from a meteorological point of view, is now chiefly in its 

 long series of observations, which date from the year 1666 ; 

 since the establishment of the Central Meteorological Office, 

 meteorology has not been actively pursued at the Observatory. 

 The Montsouris Observatory was founded in 1871, and deals 

 chiefly with the collection of hygienic statistics, and the apjjlica- 

 tion of meteorology to agriculture. It publishes an Annuaire, and 

 also a monthly summary in the Comptes rendus of the French 

 Academy. Prof H. A. Hazen contributes an article on ane- 

 mometer comparisons, and discusses the results of recent ex- 

 periments in America and in this country, with the view of 

 determining the ratio between the motion of the wind and that 

 of the centre of the cups. The results of the American experi- 

 ments have been discussed by Prof Marvin, and will shortly be 

 published in extenso. The chief difficulty lies in the determina- 

 tion of a constant factor for all velocities, and of constants 

 for diff'erent sizes of cups and arms. Prof. Hazen thinks it 

 possible to construct an anemometer with arms and cups 

 so proportioned as to give a constant factor at all velocities. 

 Lieutenant Finley discusses the frequency of tornadoes in the 

 State of Georgia during the last ninety-four years. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, May 9.— "On the Magnetic Rotation of 

 the Plane of Polarization of Light in doubly refracting Bodies." 

 By A. W. Ward. Communicated by Prof. J. J. Thomson, 

 F.R.S. 



In repeating Villaii's experiment on the rotation of the plane 

 of polarization of light in a spinning disk of heavy glass, placed 

 with its axis of rotation perpendicular to the lines of force in a 

 magnetic field, it was observed that the incident plane-polnrized 

 light became elliptically polarized. The elliptic p<ilarization was 

 due to the centrifugal force, which had the effect of stretching the 

 glass along the radii of the disk and compressing it parallel to 

 the axis of rotation. The strained glass in the magnetic field 

 has, therefore, the double property of elliptically polarizing plane- 

 polarized light, and at the same time rotating the plane of 

 polarization. The strained glass therefore acted like a crystal 

 placed in a magnetic field, and so, bef ire Villari's experiment 

 could be properly interpreted, it is necessary to examine how 

 the elliptic polarization and magnetic rotation affect each other. 

 The following investigation is an attempt to solve this question, 

 and its conclusions show that the apparent magnetic rotation in 

 a doubly refractive medium is a periodic function of the length 

 of the path of light in the medium. This hitherto unsuspected 

 result entirely accounts for the effects observed by Villari, and 

 those observed by Liidtge in a piece of compressed glass. 



Villari's results are very similar to Liidtge's. Villari, by 

 spinning a disk of glass very rapidly, strained it, and on observ- 

 ing the magnetic rotation found it get less and less as the strain 

 got greater and greater. There is, however, one noticeable 

 difference between Villari's strained disk and Liidtge's strained 

 prism. The disk was free from strain in the middle, the prism 

 free from strain at the ends. 



I have repeated Villari's experiment at the Cavendish 

 Laboratory, using, at Mr. Glazebrook's suggestion, an elliptic 

 analyzer to determine the magnetic rotation. With the disk 

 spinning about 200 times a second, the magnetic rotation was 

 reduced from lo'" to 6°. This is not so great a diminution as 

 Villari observed, but his glass may have been softer and more 

 easily strained. 



Villari thought that the effect he observed was due to the time 

 required to magnetize the glass. That this supposition was erro- 

 neous has been clearly established by the experiments of Bichat 

 and Blondlot, and recently repeated by Dr. Lodge. In these 

 experiments the oscillating discharge of a Leyden jar was found 

 to rotate the plane of polarization in time with the oscillations. 

 Before hearing of these results I had myself attacked the 

 problem in a somewhat similar manner. A coil of wire was 

 wound round a piece of heavy glass, and a current alternated 

 250 times a second by a tuning-fork was sent through the coil. 

 The current was measured by a dynamometer and a tangent 

 galvanometer. The first gave the measure of the current in- 

 dependently of its sign, the second showed that the integral 

 current was zero. When the current was passing it was found 

 impossible to extinguish the light, owing to the rapid alternations 

 of the plane of polarization. 



May 16. — "Physiological Action of the Active Principle 

 of the Seeds of Abrus precatorius (Jequirity)." By Sidney 

 Martin, M.D. London, British Medical Association Research 

 Scholar, Assistant Physician to the Victoria Park Chest Hospital ; 

 and R. Norris Wolfenden, M.D. Cantab. (From the Physio- 

 logical Laboratory, University College, Lonc'oii.) Communicated 

 by E. A. Schiifer, F.R.S. 



" The Toxic Action of the Albumose from the Seeds of 

 Abrus precatorius.'''' By Sidney Martin, M.D. Lonilon, British 

 Med'cal Association Research Scholar, Assistant Physician to 

 the Victoria Park Chest Hospital. (From the Physiological 

 Laboratory, University College.) Communicated by E. A. 

 Sclafer, F.R.S. 



From numerous experiments, the following conclusions were 

 arrived at : — 



(i) The poisonous activity of the seeds oi Abrus precatorius, 

 the jequirity, resides in the two proteids present in the seeds — a 

 paraglobulin and an albumose. 



(2) Both of these proteids have practically the same action. 

 They produce severe conjunctivitis when applied to the eye ; 

 and when subcutaneously injected, they cause local inflamma- 



