2l6 



NATURE 



[June 30, 1887 



modification, one of the effects of which is the deviation of the 

 equipotential lines. It also occurred to him that this modifica- 

 tion of structure should produce on a calorific flux the same 

 alterations as on an electric current, and the experiments here 

 described have fully confirmed these anticipations. — Application 

 of the electrometer to the study of chemical reactions, by M. E. 

 Bouty. In the author's last communication the problem was 

 resolved in principle regarding the application of the electro- 

 meter to the study of chemical reactions. Here the subject is 

 illustrated by the example of sulphuric acid and the sulphate of 

 potassa. — On a new regulator of electric light, by M. Letang. 

 The object of this apparatus is to obtain a distinct regulating 

 control by means of a simple contrivance independent of any 

 complicated machinery. The means employed to arrive at this 

 result are based on the employment of a mechanism analogous 

 to that of an ordinary system of electric chimes. — On the man- 

 ganites of potassa, by M. G. Rousseau. The formation has already 

 been described of a manganite of potassa by calcination of the per- 

 manganate at 240° C. But this method is useless for studying the 

 variations of the molecular state of manganous acid combined 

 with potassa under the action of a progressively increasing 

 temperature. Hence the author has had recourse to the dissocia- 

 tion of the manganate of potassa in presence of an alkaline 

 dissolvent. 



Berlin. 



Physical Society, June 10. — Prof. Du Bois-Reymond, 

 President, in the chair. — In connexion with his previous com- 

 munications on the determination of the wave-length of light by 

 the weight of a cube of quartz, Dr. Sommer spoke on the methods 

 of determining the specific weight of bodies, with special re- 

 ference to the method by weighing them in water. After 

 having discussed the earlier methods and experiments of 

 Marck and Lepiney, he gave an account of the methods 

 he ..had himself employed in order to do away with the in- 

 fluence which the capillary forces at the surface of the water 

 exert on the wire by which the solid is suspended. He surrounds 

 the wire at the point where it enters the water with a glass tube 

 5 mm. in width, in which is placed one drop of a mixture of 

 equal parts of olive-oil and benzene. From the lower end of 

 the wire in the distilled water he hangs a tiny tray on which two 

 cubes of quartz are placed. Using a wire o*i mm. in diameter, 

 which he finds gives a result as accurate as weighing in air, 

 he determines the weight of these quartz cubes in water, then 

 pushes one of the cubes off the tray by means of a platinum 

 wire which had been previously submerged, and weighs 

 again. He then pushes the second cube off" the tray and 

 weighs a third time. These three weighings, taken in con- 

 junction with the weight of the tray and cubes in air, yield an 

 exactitude which up to the present time has either not been at- 

 tained at all by hydrostatic methods or only by a laborious and 

 roundabout process. The exactness of this method of determin- 

 ing the specific weight of quartz cubes surpasses that obtained 

 by the use of a piknometer. — The President gave an account of a 

 communication which had been made by Siemens at the last 

 meeting of the Akademie der Wissenschaft. A steel tube 10 cm. 

 long, with perfectly smooth external and internal surfaces and 

 extremely uniform bore, and whose walls are apparently of per- 

 fectly equal thickness at all points, was prepared by the following 

 method, patented by Mannermann in Bemscheid. Two rollers, 

 slightly conical towards their lower ends, are made to rotate in 

 the same direction near each other; a red-hot cylinder of 

 steel is then brought between these cylinders and is at once 

 seized by the rotating cones and is driven upwards. But the 

 mass of steel does not emerge at the top as a solid, but in the 

 form of the hollow steel tube which Siemens laid before the meet- 

 ing. Prof. Neesen gave the following explanation of this 

 striking' result : owing to the properties of the glowing steel, the 

 rotating rollers seize upon only the outer layer of the steel 

 cylinder and force this upwards, while at the same time the 

 central parts of the cylinder remain behind. The result is 

 thus exactly the same as is observed in the process of making 

 glass tubes out of glass rods. 



Stockholm. 

 Royal Academy of Sciences, June 8. — Monograph of the 

 Amphipoda Hyperiidea, part 2, by Dr. C. Bovallius. — Fresh- 

 water Algae, collected by Dr. S. Berggren in New Zealand, and 

 described by Dr. O. Nordstedt. — On a manuscript map of Scan- 

 dinavia from the middle of the fifteenth century, found in the 

 library of Comte Zamoisky, in Warsaw, by Prof A. E. 



Nordenskiold. — On the sequence of the Glacial beds, and 

 the temperature during the various stages of the Ice epoch. 

 Prof. O. Torell. — On the anatomy of Hyperoodon diodon. 

 Miss A. Carlsson. — Some reptiles and fishes showing the 1 

 called third eye, exhibited and demonstrated by Prof. F. 

 Smitt. — Desmidiaceffi from Greenland, described by Herr 

 Boldt. — On the distribution of Desmidiaceae in the north( 

 regions, by the same. — Contribution to the knowledge of 1 

 anatomical structure of the Dioscoreee, by Herr J. P. Jungn 

 — Studies on the spectra of absorption of the rare elements, 

 Prof. L. F. Nilsson and Dr. G. Kriiss. — An attempt to cah 

 late the dissociation in the water of solution, by Dr. S. Arrl 

 nius. — Contributions to the theory of undulations in a gasec 

 body, by Prof A. V. Backlund. — On the changes in volui 

 and density of fluids through absorption of gases, by Dr. '. 

 Angstrom. — On the form of the crystals and twin-crystals 

 scolecite from Iceland, by Herr G. Flink. — Mineralogical noti 

 by the same. 



BOOKS, PAMPHLETS, and SERIALS RECEIVE! 



The British Moss Flora, Part x. : R. Braithwaite. — An Introduction 

 the Study of Embryology : A. C. Haddon (Griffin).— Pola seine Vergang. 

 heit, Gegenwart und Zukunft ; eine Studie (Wien).— Mount Taylor and 1 

 Zufii Plateau : Capt. C. E. Dutton (Washington).— Bulletin of the U 

 Geological Survey, No. 38 (Washington). — Annalen der Physik und Chem 

 1887, No. 7(Barth, Leipzig). 



CONTENTS. PAC 



Forestry i 



Observations at Godthaab i 



Our Book Shelf ;— 



Wilson: " Essays and Addre.'^ses " i' 



Page : " Introductory Text-book of Physical Geo- 

 graphy" V 



" Longman's New Geographical Reader " i< 



Letters to the Editor : — 



The New Degrees at Cambridge. — C. T i< 



Weight, Mass, and Force. — Prof. A. G. Greenhill . i( 

 Upper Cloud Movements in the Equatorial Regions of 



the Atlantic. — Capt. David Wilson-Barker . . i( 

 The Shadow of Adam's Peak. — Hon. Ralph Aber- 



cromby i< 



Temperature and Pressure. — Maxwell Hall .... I< 

 British Association Sectional Procedure. — Dr. Alfred 



W. Bennett ' ic 



Mirage. — Dr. Chas. O. Trechmann ic 



A Suggestion for Anthropologists. — Dr. William F. 



Warren ic 



Snow in Central Germany. — Dr. Otto Knopf . . , ic 



Meteor.— Capt. H. King, R.N ig 



Medicine in McGill University. — Prof. T. Wesley 



Mills IC 



The University of Tokio.— Prof. S. Sekiya .... ic 



Science for Artists. {Illustrated) ic 



A Review of Lighthouse Work and Economy in the 

 United Kingdom during the Past Fifty Years. III. 



By J. Kenward 2C 



Report of the Board of Trade on Weights and 



Measures 20 



The German Meteorological Office. By J. S. 



Harding 2C 



The Height of Summer Clouds 2C 



Ivan Polyakoff 2( 



Notes m. 



Astronomical Phenomena for the Week 1887 H 



July 3-9 * ' 



Geographical Notes 2: 



Discovery of Fossil Remains of an Arctic Flora inM 

 Central Sweden. By Prof. A. G. Nathorstj ■ • • ■ 



Geological Structure of Finistere ■ 



Temperature in Relation to Fish ■ 



Societies and Academies 1 



Books, Pamphlets, and Serials Received 



i 



