NA TURE 



\_Jan. I, 1885 



sublime, was closed at the top by a stopper through which 

 in sed two small tubes, one reaching to the bottom, the other 

 coming out below the stopper. The first small tube was con- 

 nected with the condenser, and by this means the tube became 

 permanently cooled. The cold tube was let down into the vessel 

 in which the substance to be sublimed was being heated, and 

 the products were obtained on the outside of the little tube, from 

 which they could be easily removed. By a platinum tube in the 

 platinum retort the speaker received molybdenous acid crystals, 

 and, by the heating of lime, microscopic lime crystals.— Prof. 

 Landolt further described an arrangement of a sodium lamp for 

 a polarimetric apparatus in which a uniformly bright flame was 

 produced, and he also showed a theodolite with a glass scale, 

 which could be read by transmission of the incident light, thus 

 facilitating observation. 



Physiological Society, November 29, 1884. — Prof. Wal- 

 deyer exhibited a microscope-stand which he found very practic- 

 able, both for the ease and security with which it enabled a micro- 

 scope to be turned in any direction, and for the way in which it 

 allowed the use of any system of lenses. — Prof. Du Bois-Rey- 

 mond spoke on the difficulty of determining the blood pressure 

 in the capillary vessels, and discussed the method he had adopted 

 in his lectures for the presentation of correct views on this 

 matter. As was known, the blood-pressure in the capillary 

 vessels had hitherto been determined by placing a small glass 

 plate on a spot of skin and then estimating the pressure that was 

 necessary to render this spot void of blood. By this method, 

 however, the elasticity of the inter-capillary tissues was left out 

 of account, and the results were therefore vitiated, so far as the 

 determination of the pressure in the capillaries was concerned. 

 The exact state of the case, which it was difficult for any experi- 

 mental examination to come at, was, in the first place, able to 

 be determined only under ideal conditions. In the current of an 

 incompressible and inexpansible fluid through a system of pipes 

 under a given propelling force the rate of current was always in 

 inverse proportion to the cross section, while, with the distance of 

 the propelling force, the pressure abated at a rate proportionate to 

 the resistance, i.e. it sank more rapidly in narrow, and more slowly 

 in wide, tubes. If a tube were widened by splitting it into two 

 branches of equal calibre, the proportions between lateral section, 

 rate of current, and pressure reaiained the same. If, on the other 

 hand, the bore became as large again as before, the rate of cur- 

 rent sank to a half, while the pressure decreased but little. If, 

 again, a capillary network were intercalated into the system of 

 pipes, the rate of current fell only in proportion to the enlarge- 

 ment of the total cross section ; the pressure, on the other 

 hand, sank considerably on account of the resistance presented 

 by the capillaries, and the curve of pressure showed a very steep 

 decline in relation to the abscissae of the zero-line. If the capil- 

 laries again merged into simple tubes, the cross section became 

 less, the rate of current proportionally greater, while the pressure 

 again sank but slowly. In the middle of the capillary system 

 the pressure, in accordance with known laws, amounted to 

 half the initial pressure. In the circulation of the blood 

 the cross sections of only the larger arteries and veins 

 were known ; the cross section of the capillary system 

 was unknown. Un ler the ideal conditions, however, which 

 formed the basis of the above scheme this cross section might 

 be calculated from measurable rates of current. Suppose the 

 rate of current of the blood in the capillary vessels equal 

 to o-8 mm. per second, and that in the aorta equal to 500 mm. 

 per second, then the current in the latter was 625 times as swift 

 as that in the capillaries, and the cross section of the whole 

 capillary system must be 625 times as large as that of the aorta, 

 or the diameter of all the capillaries was twenty-five times as 

 large as the diameter of the aorta. The curve of pressure sank 

 slowly in the arterial system. In the capillaries the great resist- 

 ance required a very considerable difference of pressure, and the 

 curve of pressure sank, therefore, very considerably ; to sink 

 more slowly in the veins down to beneath the abscissa line, i.e. 

 the pressure in the veins in the neighbourhood of the heart 

 became negative. In the middle of the capillary system the pres- 

 sure, in accordance with this view, was equal to half the pressure 

 in the ventricle. Should the arteries in consequence of the con- 

 traction of their smooth muscle-fibres become narrower, the point 

 where the pressure in the capillaries was equal to half the heart s 

 pressure shifted nearer to the arterial system. If, on the other 

 hand, contractions or obstructions occurred in the veins, this 

 point came closer to the venous system. Such a presentation of 

 the case gave a view of the conditions of cross section and 



pressure in the capillaries, and offered a basis for experimental 

 investigations. A scheme of the same kind might be applied 

 to thesystem of lymphatic vessels, for which the average pres- 

 sure in the blood capillaries must be taken as starting pressure. 

 — Prof. Fritsch related an optical phenomenon he had perceived 

 during the microscopical examination of certain objects, a 

 phenomenon he described as due to monocular stereoscopic 

 vision. Certain pictures, in particular those of the transverse 

 section of the principal nerves of the electric organ, mad a 

 decided impression of a funnel-shaped depression such as was 

 otherwise obtained only in the binocular contemplation of the 

 well-known stereoscopic figures. It was especially easy for him 

 to receive this impression on moving his eye from side to side. 

 By producing the arrangement he had referred to at the next 

 sitting of the Society, he would ascertain whether other eyes 

 received the same impression of the picture. 

 Vienna 



Imperial Academy of Scien:es, December 4, 18S4. — 

 On the scientific usage of orthogonal axonometers, by C. Pelz.— 

 On the mechanical theory of electricity, by T. Tanuschke. — On 

 energy and coercive state in the magnetic field, by G. Adler. 

 On the consumption of some foods in the intestinal tract of man, 

 by H. Malfatti. — Contribution to a knowledge of some hydro- 

 products of cinchoninic acid, by A. Weidel and K. Hazura. — 

 On the action of the sun-spectrum on the haloid comp mnds oi 

 silver, and on the raising of their sensibility to some parts of 

 the spectrum by colouring-matters and other substances, by T. 

 M. Eder.— Computation of the orbit of the planet Russia 232, 

 by N. Herz. 



December II, 1884.— On morin, part 2, by R. Benedikt and 

 K. Hazura. — Communication on the determination of nitrog n. 

 by G. Czeczetka.— Studies on the compounds prepared from 

 animal tar ; part 5, on collidine, by H. Weidel and B. Pick. 



December 18, 18S4. — On deformation of the plane of light- 

 waves in the magnetic field, by E. von Fleischl. — Contributions 

 to the explanation of cosmic-terrestrial phenomena ; part 2, on 

 aurora borealis, by T. Unterweger. — On Kjehldahl's method 

 for determining nitrogen, by G. Czeczetka. — On central eclipses 

 of the sun of the twentieth century, by E. Mohler. 



CONTENTS Page 



The " American Journal of Mathematics " .... 1S9 



A System of Psychology 190 



Our Book Shelf:— 



Hooker's " Student's Flora of the British Islands " . 191 



Claus's " Elementary Text-Book of Zoology " . . . 191 



Strausz's " Bosnien, Land und Leute " 19 2 



Letters to the Editor : - 



The Solar Corona and After-Glow.— Henry F. 



Blanford, F.R.S 192 



Flying-Fish do not Fly.— Dr. K. Mdbius .... 192 

 Iridescent Clouds— T. W. Backhouse ; C. J. P. ; 



James I'Anson ; W. W. Watts 19 2 



The Rotation of Neptune. — Maxwell Hall .... 193 



Peculiar Ice-Forms.— B. Woodd Smith 193 



Lightning in the Tropics.— J. J. Meyrick .... 194 

 An Unnoticed Factor in Evolution.— J. Jenner 



Weir 194 



A Large Meteor.— Otto Boeddicker 194 



The Formation of the Solar System 104 



Berzelius and Wohler. By Prof. T. E. Thorpe, 



F.R.S '96 



American Storm Warnings 197 



The Actiniae "»^ 



The Earthquake in Spain. By F. Gillman ; Alfred 



Batson, (Illustrated) "99 



The Habits of the Limpet. By J. R. Davis . • . . 200 



The Mediterranean Fauna 201 



Our Future Clocks and Watches. (Illustrated) . . 201 



Notes 2 ° 2 



Physical Notes 2 °a 



Chemical Notes • ... 204 



Geographical Notes 2 °4 



Report of the London School Board Committee on 



Technical Education 205 



University and Educational Intelligence 209 



Societies and Academies 2 °9 



