I20 



NA TURE 



[Nov. 29, 1888 



small, so that the liminal intensity (Schwellcmverth) for small 

 sm-faces is considerably greater than for large. — Prof Kundt 

 exhibited a large number of photograph; of spectra which had 

 been prepared in his laboratory with a view to testing the action 

 of light-absorbing substances on dry-plates. Spectra photo- 

 graphed on dry-plates which had been coloured with chlorophyll 

 were especially interesting. They consisted of a bright strip 

 ending near Y , followed by a dark portion intercepted by an 

 extremely bright line at the spot where the absorption -band of 

 chlorophyll is present in the red. Plates stained with eosin 

 similarly showed a bright strip corresponding to the absorption- 

 band of this substance in the yellow, whose brightness was much 

 greater than that of the rest of the spectrum. These experiments 

 showed that the rays of light which are absorbed by the above 

 colouring- matters exert an extremely active chemical action on 

 the plates. Experiments made with a view to determining 

 whether absorption of light has a similar effect on fluorescence 

 yielded negative results. It still remains to investigate whether 

 the maximum brightness of the spectrum photographed on a 

 plate stained with chlorophyll corresponds exactly with the 

 absorption-band of this substance, taking into account at the 

 same time the influence of the solvent used for the solution of 

 the chlorophyll on the position of its absorption-band. Prof. 

 Kundt then exhibited a simple form of bolometer which, based 

 on the principle described by Dr. R. von Hehnholtz at a recent 

 meeting of the Society, may be easily and cheaply constructed 

 out of thin tinfoil, and is specially adapted for lecture experi- 

 ments. The same speaker finally exhibited two selenium cells 

 constructed by Uljanin, of Strasburg, in July 1887, and still 

 extremely sensitive to the action of light. 



Meteorological Society, November 6. — Dr. Vettin, Presi- 

 dent, in the chair. — Dr. Kremser gave an account of meteoro- 

 logical observations made during a balloon voyage on June 23 of 

 this year. For the purpose of carrying out scientific observations 

 on the lines of Welsh and Glaisher in England, and of Tissandier 

 in France, von Siegsfeld had constructed a balloon fourteen 

 metres in diameter. — Dr. Assmann described some ice-filaments 

 which he had observed in a valley of the Harz Mountains during 

 a three days' frost in October. 



Physiological Society, November g.^Prof du Bois- 

 Reymond, President, in the chair. — Dr. Virchow described, as 

 based on his own original researches, the development of the 

 cylindrical epithelium of the yolk-sac, thus amplifying the com- 

 munication made at the previous meeting of the Society on the 

 development of the blood, blood-vessels, and yolk-sac of the 

 chick. He distinguished seven stages in the development of the 

 epithelium, each of which he separately described and explained 

 by means of drawings, diagrams, and preparations, which he 

 exhibited. — Dr. Martins made a communication on new experi- 

 ments which he had carried out with a view to refuting certain 

 attacks which had been made on his investigation of cardiograms 

 as laid before the Society in the previous year. It may be re- 

 membered that the speaker had connected the curves traced by 

 the impulse of the apex of the heart on a rotating cylinder with 

 the various phases of a cardiac cycle, by auscultating the heart, 

 and recording each sound he heard by a mark on the same 

 rotating drum. Since he had assured himself that he could 

 record the above without any irregularity due to his own reaction- 

 time, he considered that the point on the cardiogram which 

 corresponded with the mark for the first sound of the heart was 

 synchronous with the closure of the auriculo-ventricular valves : 

 the point corresponding to the mark indicating the second sound 

 of the heart he regarded as coincident with the closure of the 

 semilunar valves. Objections were made to the above method, 

 and the possibility of the observer's reaction- time not being zero 

 was left out of account. In answer to these. Dr. Martius has 

 now made some new experiments with a pendulum beating 

 seconds which closed an electric circuit as it passed through the 

 vertical : the current thus produced attracted an armature, made 

 a clapper-like noise, and recorded the instant of its production 

 on a rotating drum. A second circuit was arranged for momen- 

 tary closure by the observer, yielding a recording mark on the 

 same drum : this circuit was closed regularly each time the 

 clapper was heard, and the two marks made in the way indicated 

 above coincided to within differences of time of at most 0*03 of 

 a second, an exactitude which amply sufficed for the investigation 

 of the ca'"diograms. It may be remarked here, as a matter of 

 theoretical interest, that the above is not a case really involving 

 reaction-time, but only the recording of known signals which 



are repeated rhythmically at regularly recurring intervals. With 

 these rhythmic stimulations the duration of the interval is usually 

 estimated, and in such cases the- variations in the time- value of 

 the estimate are mostly greater than those just quoted. When, 

 however, after some time the rhythm of the stimulations has 

 been fully grasped by the observer, then the interval is no longer 

 estimated, but the record is made with an exactly similar 

 rhythm. 



Stockholm. 

 Royal Academy of Sciences, November 14.— Musci 

 Asise borealis, first part, I.ivermosses, by Prof. G. O. Lindberg 

 and Dr. H. W. Arnell. — The disguise of the Decapodaoxyrrkina 

 through special adaptations of the structure of their body, by Dr. 

 Carl Aurivillius. — On the bladders of the Fucacese, by Dr. N. 

 Wille. — Mineralogical notes, by Herr G. Flink. — On the journey 

 of Dr. Nansen on the inland ice of Greenland, by Baron 

 Nordenskiold. — Contributions to the knowledge of the Cestodean 

 worms which occur in Sweden, by Herr E. Lonnberg. — On a 

 monstrous individual of Cottus scorpius, by Herr E. Nystrcim. — 

 Annotations of some Scandinavian Pyrenomyceta?, by Herr K, 

 Starback. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Meteorological Observations at Stations of the Second Order for the year 

 1884 (Eyre and Spottiswoode).— A Sketch of the First Principles of Physio- 

 graphy: J. Douglas (Chapman and Hall). — Rocks and Soils; H. E. Stock- 

 bridge (Trubner). — The Floating Island in Derwentwater : G. J. Symons 

 (Stanford). — Prodromus of the Zoology of Victoria, Decade xvi. : F. McCToy 

 (Triibner). — The Principles of Cancer and Tumour Formation : W. R. 

 Williams (Bale).— The World's Inhabitants : G. T. Bettany (Ward, Lock).— 

 A 1 realise on Hydrodynamics, vol. ii. : A. B. Basset (Bell). — Results of 

 Observations at Stonyhurst College Observatory, 1887 : Rev S. J. Perry. — 

 Mcrphologisches Jahrbuch, 14 Band, 3 Heft (Williams and Norgate). 



CONTENTS. Page 



Hauptmann on Harmony and Metre. By Dr. W. 



Pole, F.R.S • 97 



Botany of Socotra 99 



The Metallurgy of Gold. By Prof. W. C. Roberts- 

 Austen, F.R.S 100 



Our Book Shelf:— 



Thorell : " Viaggio di L. Fea in Birmania e regioni 



vicini."— Rev. O. P. Cambridge, F.R.S. ... 100 

 Jago : " An Introduction to Practical Inorganic 



Chemistry" loi 



Letters to the Editor :— 



Engijieers versus "Professors and College Men." — 



Prof. P. G. Tait loi 



The Great Modern Perversion of Education. — Hon. 



Auberon Herbert 102 



Mr. Dyer on Physiological Selection. — Prof. George 



J. Romanes, F.R.S 103 



Cleistogamy. — Rev. George Henslow 104 



Nose-Blackening as Preventive of Snow-Blindness.— 



J. D. La Touche 105 



Amber. — Dr. A. B. Meyer 105 



On the Mechanical Conditions of a Swarm of 



Meteorites. II. By Prof. G. H. Darwin, F.R.S. . 105 

 Edison's Perfected Phonograph. {Illustrated.) . . . 107 

 Further Notes on the Late Eruption at Vulcano 

 Island. By Dr. H. J. Johnston-Lavis ...*.. 109 



Notes Ill 



Our Astronomical Column : — 



Comet 1888 £ (Barnard, September 2) 114 



Comets Faye and Barnard, October 30 114 



The Satellite of Neptune 114 



Astronomical Phenomena for the Week 1888 



December 2-8 114 



Geographical Notes 115 



The Renaissance of British Mineralogy. By L. 



Fletcher 115 



University and Educational Intelligence 117 



Societies and Academies 117 



Books, Pamphlets, and Serials Received 120 



