ij6 



NATURE 



[June 28, 1877 



pounds, so long as the boiling-points at the ordinary pressure of 

 Ihe atmosphere alone are taken into account. 



Mathematical Society, June 14. — Lord Rayleigh, F.R.S., 

 president, in the chair. — Prof. Crotton, F.R.S., proved some 

 geometrical theorems relating to mean values. These theorems 

 were chiefly interesting as examples of the employment of the 

 theory of probability to establish mathematical results ; they 

 were of a kindred nature with theorems given in the I'nil. 

 Trails., 186S, p. 185, and in Williamson's " Integral Calculus," 

 second edition, p. 329. Mr. Merrifield made a few remarks on 

 the communication. — Prof Clifford, F. R.S. , read a paper on the 

 canonical form and dissection of a Riemann's surface. The object 

 of the paper is to assist students of the theory of complex 

 functions by proving the chief propositions about Riemann's 

 surfaces in a concise and elementary manner. To this end 

 certain results of Puisenx's were assumed at the outset. Prof. 

 Smith in making remarks on the paper expressed his in- 

 debtedness to the author in having cleared up a difficulty which 

 presents itself in Liiroth's paper on the subject. — Prof. II. J. S. 

 Smith, F.R. S., gave a short account of a further communication 

 upon Eisenstein's theorem. — Mr. Tucker communicated a paper 

 by Mr. J. C. Malet entitled, " Proof that every Algebraic Equa- 

 tion has a Root." — The Society's next meeting, will be held 

 on the second Thursday in November. 



Royal Astronomical Society, June 8. — Dr. Huggins, 

 F.R.S., in the chair. — .Some tables for facilitating the computa- 

 tion of star constants were presented by Mr. Stone. — Mr. Marth 

 explained diagrams referring to conjunctions of Saturn and Mars 

 between July and November next — being a triple conjunction. — 

 Dr. Royston Pigott described a method of collimating reversible 

 instruments by which the error could easily be determined within 

 2". Mr. Dunkin intimated that he would be greatly disappointed 

 to find his collimalion o"'25 out. — Mr. Gill recounted some of 

 the troubles that beset people who go after parallax, and de- 

 scribed some methods of getting rid of systematic errors.— The 

 president in the name of the mteting said " Good-bye" to Mr. 

 Gill on the eve of his departure for the Island of Ascension. — 

 At 9 r. M. the proceedings were stopped by the president to leave 

 time for the special meeting called to consider a proposed altera- 

 tion in the bye-laws. 



Paris 



Academy of Sciences, June 18. — M. Peligot in the chair. — 

 The following papers were read : — On the notation of Berzelius, 

 by M. I'.erthelot. — Some observations on the mechanism of 

 chemical reactions, by M. Berthelot. The new facts observed 

 relate to direct oxidation of haloid salts, and of sulphurous and 

 arsenious acids. — On the order of appearance of the first vessels 

 in the aerial organs of some Primula, by M. Trecul. — On the 

 crystalline form and the optical properties of proto- iodide of 

 mercury, by M. Des Cloizeaux. The ciystals generally occur in 

 the form of thin, flexible, weakly dichrfjic plates, of the quad- 

 ratic system, but liable to be mistaken (or a clinorhombic com- 

 bination. Across the planes of cleavage they give strong double 

 refraction, with positive axis. The salt is completely isomor- 

 phous with calomel (or the protochloride) ; and it is imperfectly 

 so with red bi-iodide of mercury, which, however, has a iirgalive 

 axis. M. Berthelot, in view of such facts, remarked on the 

 uncertainty they throw on the employment of isomorphism 

 as a method for determining the number of atoms con- 

 tained in a compound, and consequently the absolute value of 

 the atomic weights. — Reply to the observations of M. Mouchez, 

 by M. Villarceau. — On M. ^'illarce.au's A'l'iirvaii A'cn-ignfion, 

 by M. Mouchez. — On the interior sea of the Algerian Sahara, 

 by M. Favc. The slope at the borders of the lake, he points 

 out, would be very pronounced. — Theory for finding the number 

 of variants and contravariants of given order and degree linearly 

 independent of any system of simultaneous forms containing any 

 number of variables (continued), by Mr. Sylvester. — On the 

 present state of the solar atmosphere ; letter from P. Secchi. 

 In presenting a resiimf of the spots and protuberances of 1S76, 

 he gives his reasons for thinking the sun in a state of relative 

 (not alisoliite) calm. M. Janssen's view that there is rather a 

 tendency to speedy dissolution of spots than a state of (even 

 relative) calm, implies, he thinks, the false idea that spots can 

 be maintained for long without the continuance of eruption. 

 Their short duration indicates a short time of eruption, therefore 

 weak solar activity. Spots continue because the dissolved 

 matter is replaced by freshly erupted matter. We have no 

 proof, either, that dissolution is more rapid at the periods of 



minimum. There are now signs of re-awakening activity. —On 

 electro-magnets with rundles of iron, by M. Du Moncel. He is 

 led to study these again by experiments of M. Fridblatt and M. 

 Jablochkoff. The lateral action of the magnetising currents on 

 the rundles is limited, he thinks, to a simple dynamical reaction 

 between parallel currents, which may, with very strong currents, 

 make plates of iron adhere strongly to the cheeks of the spiral, 

 but which does not develop exteriorly on these plates well-marked 

 magnetic polarities. This latter only occurs where the plates are 

 so small that the spirals act on them by enveloping them like a 

 core. — On the use of sulpho-carbonates and sulphide of carbon 

 in treatment of the vine, by M. Mares. — On a temporary affec- 

 tion of sight, by M. Pierre. Reading, one day, after having had 

 brain fever, a glazed volume, he found the characters apparently 

 more distant than the paper (about 4 mm. ) ; and the exerci.se 

 was very fatiguing. In the next eight or ten days the characters 

 seemed gradually to come nearer to the surface. — Historical 

 remarks on the theory of motion of one or several constant or 

 variable forms in an incompressible fluid, &c. (continued), by M. 

 Bjerknes. — ^Determination of groups formed of a finite number 

 of linear substitutions, by M. Jordan. — On the metallic solar 

 eruptions observed at Palermo from 1S71 till April, 1S77, by M. 

 Tacchini. In 1S71 the zone of eruptions was confined between 

 + 70° and — 40" ; in 1S76 it extended only between zero and 

 — 21°; and in the first four months of 1877 there has only 

 been one very small eruption. — On a new general method of 

 synthesis of liydrocarbons, acetones, &c., by MM. Friedel and 

 Crafts. — Reducing action of phosphorus on sulphate of copper; 

 phosphides of copper, by M. Siiot. — Chemical researches on 

 crystallised carbonite of lead formed on objects found at Pompeii, 

 by M. de Luca. — Observations on some xanthates ; separation 

 of cobalt and nickel, by M. Phipson. — Researches on tetra- 

 chloride of carbon and its employment as an ancesthetic, by M. 

 Morel. 1 le w.as led to this application of it by the similarity of 

 its formula (C^Clj) to that of chloroform (C0HCI3). It is found 

 a perfect anx-sthetic and more powerful than chloroform, but 

 quite capable of being regulated. The periods of insensibility 

 and collapse are identical with those of chloroform ; that of ex- 

 citation is more pronounced. A mode of preparing the substance 

 is described. — Observation of a bolide at Clermont-Ferrand on 

 June 14, 1S77, by M. Grerey. The head was about five to six 

 minutes apparent diameter ; the light was bright and flashing, 

 with slight reddish and bluish gleams. No sound was perceived. 

 —On a solar halo, by M. Vinot. 



CONTENTS Pack 



Soldiers' Rations. By H. Bahen Peitchard 157 



Geikie's "Physical Geography " 158 



The Laboratory Guide 160 



Our booK Shelf ; — 



Kropotkio'-s " Researches on the Glacial Period " 161 



Letters to the Editor : — 



Indian Rainlall and Sun-spots.— Prof. Balfour Stewart, F.R.S. i6i 



Natural History Museums — Wh. Watts, V G.S l6i 



Koenig's Tuning Forks.— Rudolph KoENiG 162 



Antiquity of Man.— Thomas Belt ; SvdnbyE. J. .'^kertchly . 162 

 Colour-Sense in Birds— Blue and Yellow Crocu.^es.— W. B. Teget- 



meiee 163 



Purple Verbenas —A. M. Darby 163 



Japanese Mirrors —Sylvanus P. Thomtson 163 



Note on the Electrical Disturbance which accompanies the 

 Excitation of the Stigma of Mimulus Luteus. By Prof .1. 



Burdon-Sanderson, F.R.S 163 



Taunton College School 164 



On Drops. By A. M. Worthington (Wim ///wj/ra/jowj) ... 165 

 Chemical Notes;— , „ ■■ r „ j 

 On Errors in the Determination ot the Densities of Mixed 



V.ipours ^67 



On the Properties of Ruthenium 167 



Aconitic Acid in Cane Juice and Raw Sugar ....... . 167 



Minerals containing Coluinbium from New Localities in the Uniled 



States 167 



Coefficient of Capillarity for Certain Liquids 167 



Meteorological Note*;: — 



Sun-spot Periods and Auroras from 1773 to 1827 767 



Sun-spots and the Prediction of the Weather of the Coming 



Season at Mauritius 168 



Meteorology in South Australia . 168 



Rainfall Observations in the East of France from 1763 to 1S70 . . 168 



Iowa Weather Report 169 



Our Astronomical Column ; — 



The Saturnian Satelhte, Hyperion i6g 



The Triple-Star 7 Camelopardi 169 



The Cape Astronomical Results for 1874 169 



The British Association at Plymouth 169 



Indian Rainfall and Sun-spots 17' 



University and Educational Intelligence 172 



Notes '73 



Societies and Academies '75 



