528 



NATURE 



{Mai^ch 29, 1888 



soil whence the roots derive the sulphate is shown to remain 

 always richer than the solution penetrating into the vessels 

 of the roots. Thus is confirmed the general law of this 

 class of phenomena, and some important inductions are drawn 

 from it in connection with the formation of the nitrates in certain 

 plants. — On the relations of atmospheric nitrogen with vegetable 

 humus, by M. Th. Schloesing. Having previously studied the re- 

 lations of vegetable earth with ammonia, carbonic acid, and oxygen, 

 the author here extends his researches to its relations with atmo- 

 spheric nitrogen. — On the actinometric observations made at Mont- 

 pellier during the year 1 887, by M. A. Crova. From these observa- 

 tions it appears that the calorific intensity, measured at noon, 

 steadily increased from the beginning of winter nearly to the end 

 of spring, attaining its monthly maximum (i'35 calorie) in May, 

 and its absolute maximum (i'54 cal. ) on the 24th of that month. 

 Then it declined rapidly, its mean value during the summer 

 being inferior to the means of other seasons. It rose, fell, and 

 again rose in autumn, during which period it acquired a new 

 maximum of i '26. These observations confirm the general laws 

 induced from the records of previous years, showing that, 

 although the epochs of maxima and minima may often be ex- 

 ceptionally displaced, the maxima of radiation occur normally in 

 spring, the minima in summer. Tables follow giving the mean 

 annual intensities and other meteorological data for the five years 

 1883-87. — On the unification of the calendar, by M. Tondini. 

 Reference is made to the recent steps taken by Italy for the pur- 

 pose of promoting the universal adoption of the Gregorian 

 calendar, which, thanks to the action of England, has already 

 replaced the Chinese system in Japan under almost insurmount- 

 able difficulties. — Remarks accompanying the presentation of a 

 model of the Fumat safety-lamp, adapted for use in mines subject 

 to fire-damp, by M. Daubree. This lamp, which has been 

 for some time in use in the Grand Combe mines, has suc- 

 cessfully withstood the severe tests to which it has been 

 subjected by MM. Mallard and Le Chatelier, and seems 

 to answer all the purposes of such an appliance quite 

 as well as any other hitherto devised. — The meridian of 

 Laghwat, by M. L. Bassot. The geodetic junction of Spain 

 with Algeria, completed in 1879, has now been extended to 

 Laghwat, 180 miles south of Algiers, and on the verge of the 

 Sahara. This carries the great meridian for the west of Europe 

 across 28° of latitude, from the northernmost point of Great Britain 

 through France and Spain to about 33° N. latitude, on the 

 confines of the desert. To the triangulation have been attached 

 the astronomic stations Gelt-es-Stel and Laghwat itself, the 

 latitude and longitude and an azimuth for each of these places 

 having been accurately determined. — On the passage of the 

 electric current through sulphur, by M. E. Duter. Sulphur, a 

 very bad conductor at the normal temperature, is here shown to 

 acquire a considerable degree of conductibility when raised to the 

 boiling-point. — On the radiograph, by M. Louis Olivier. The 

 instrument described under this name has been invented by the 

 author as a self-acting recording photometer. At each revolution 

 of the drum it closes an electric circuit, and thus automatically 

 shuts off the luminous action at any desired moment. While 

 serving in a general way as a registering apparatus for light, it 

 is capable of venous applications in photography, meteorology, 

 and physics. — On the hydrate of sulphurated hydrogen, by MM. 

 de Forcrand and Villard. Having already made known the 

 composition of this substance, HS-I-12HO, and measured its 

 tension of dissociation between -fo'5 and 29° C, the authors here 

 resume its study for the purpose of more accurately determining 

 this tension at or about the temperature of 0°. This is found to 

 be about equal to atmospheric pressure. — Experimental re- 

 searches on chronic intoxication by alcohol, by MM. A. Mairet 

 and Combemale. Having previously described the influence of 

 chronic alcoholic intoxication on the nervous and muscular 

 systems, the authors here study its effects on the heart, the 

 respiratory and digestive organs, and the bodily temperature. 



Berlin. 



Physical Society, March 2. — Prof, du Bois Reymond, Pre- 

 sident, in the chair. — Dr. Gumlich spoke on Newton's rings as 

 seen by transmitted light. The speaker had calculated and ex- 

 perimentally verified the formulae for the rings as seen by 

 transmitted light, in the same way as many years ago Prof. 

 Wangerin had treated the rings when seen by reflected light, 

 and subsequently verified the results of his calculations experi- 

 mentally in conjunction with Prof. Sohncke. The outcome of 

 Dr. Gumlich's calculation was the same as that of Prof. 



Wangerin for the rings seen by reflected light. When the 

 light is incident at right angles, the rings are circles lying in one 

 plane : when the angle of incidence is less than a right angle, 

 the rings lie on a surface of extremely complicated shape, which 

 is characterized by a primary ordinate, and an oblique ordinate 

 at right angles to the former, which do not coincide at the point 

 of intersection. By means of an apparatus which the speaker 

 showed and carefully described, he had experimentally tested 

 the accuracy of his calculations, and found them fully confirmed. 

 When the light is incident obliquely, the rings are no longer 

 circles as they are when it falls on to and passes through the 

 medium at right angles, but are now ellipses whose axes bear 

 a ratio to each other which is dependent on the angle of in- 

 cidence of the light. It was not found possible to obtain any 

 definite results as regards the width of the rings, since this is very 

 largely affected by temperature. — Dr. Sprung reported on a work 

 which had been sent in by Dr. Miiller-Erzbach [treating of the 

 determination of mean temperature by means of the weight of 

 water which is vaporized. A bulb blown on the end of a glass 

 tube is half filled with water and introduced into a wide- 

 necked flask whose bottom is covered with sulphuric acid. 

 Assuming the truth of Dalton's law of tensions. Dr. Miiller has 

 arrived at a formula by means of which the mean temperature 

 of a space can be determined from the mass of water which is 

 vaporized in a given time. — At the end of the meeting Prof. 

 Lampe discussed a reply which had been recently made to a 

 criticism of his on a piece of work done last year by Dr. Haussler, 

 and showed how devoid of foundation the reply was. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED 



Geography of the British Isles : A. Geikie (Macmillan). — Pubblicazione del 

 Real Osservatorio di Palermo, vol. iii. (Palermo). — Glen Desseray : Principal 

 Shairp (Macmillan). — Die Wechselbeziehungen zwischen Pflanzen und 

 Ameisen im Tropischen Amerika : A. F. W. Schimper (Fischer). — Encyclo- 

 paedia Britannica, vol. xxiii. (Black). — Disease, its Prevention and Cure : 

 C. G. Godfrey (Grevel). — Untersuchungen iiber Heterogenese, iii., Dr. 

 A. P. Fokker (Groaingen). — Journal of Morphology, vol. i. No. 2 (Ginn, 

 Boston). 



CONTENTS. PAGE 



Elementary Instruction in Practical Biology . . . 505 



A Text-book of Embryology 506 



A Treatise on Algebra. By Capt. P. A. Macmahon, 



R.A 508 



Our Book Shelf :— 



"My Telescope" 509 



James: " Hand-book of Perspective" 509 



Letters to the Editor : — 



Coral Formations. — Robert Irvine 509 



Professor Rosenbusch's Work on Petrology. — A. B. . 509 



" The Mechanics of Machinery." — ^J. Venn .... 510 

 The Definition of Force and Newton's Third Law. — 



Nemo , . . 511 



Green Colouring-matter of Decaying Wood. — Rev. A. 



Irving 511 



The Hittites, with Special Reference to very Recent 



Discoveries. I. {Illustrated.) By Thomas Tyler . 511 

 Timber, and some of its Diseases. VI. {Illustrated.) 



By Prof. H. Marshall Ward 514 



Notes 516 



Our Astronomical Column: — . 



The Pulkowa Catalogue of 3542 Stars for 1855 _. . . 520 

 The Constant of Precession and the Proper Motion of 



the Solar System 520 



Comet 1888a (Sawerthal) ■ 520 



Astronomical Phenomena for the Week 1888 



April 1-7 520 



The Royal Meteorological Society's Exhibition. By 



William Marriott 521 



The Botanical Department, Northern India .... 522 



The Mew Siberian Islands 522 



Earthquakes in the Levant 5^3 



The Mineral Concretion of the Teak Tree. By 



David Hooper . 523 



The New York Agricultural Station. By Prof. John 



Wrightson 524 



Scientific Serials . 525 



Societies and Academies 5^5 



Books, Pamphlets, and Serials Received 528 



