24 



NATURE 



[Nov. 7, 1878 



I have always been impressed with the strikingly inferior bright- 

 ness of Mercury as compared with Venus ; and as such a con- 

 dition is the very reverse of what might be expected by reason 

 of Mercury being so much nearer to the sun than Venus, I 

 awaited the rare event of a very close conjunction of these two 

 planets that occurred on September 26 and 27 last. With the 

 advantage of a perfectly clear sky I had the two planets before 

 me for several hours, so to speak, side by side in the field of the 

 telescope at the same time, thus affording me a most perfect 

 opportunity for making a comparison of their relative brightness. 

 It is difficult to convey in words an exact impression of the 

 diiference in the brightness of such objects, bixt I may attempt 

 to do so by stating that Venus looked like clean silver, while 

 Mercury looked like lead or zinc. Were I to indicate my im- 

 pressions by way of number I would say that Venus was fully 

 twice as bright as Mercury. So remarkable an inferiority in the 

 brightness of Mercury, notwithstanding his much greater near- 

 ness to the sun, appears to me to indicate the existence of some 

 very special and peculiar condition of his surface in respect to 

 his capability of reflecting light — a condition that may be due to 

 the nature of his envelope, if such exist, or of that of his sur- 

 face, by which the fervid light of the sun's rays falling on him 

 are in a great measure quenched or absorbed so as to leave but a 

 small residue to be reflected from his surface. If this be so, it 

 appears to me to be reasonable to suppose that the absorption 

 of so much light must result in a vast increase in the heat of the 

 surface of Merairy beyond what would have been the case had 

 Mercury possessed the same surface conditions as Venus. 

 Whether in the progress of spectroscopic investigation we shall 

 ever be enabled to detect some evidence of metallic or other 

 vapours or gases clinging to or closely enveloping the surface of 

 Mercmy that might in some respect account for so remarkible 

 an absorption of the sun's light, we must be content to await 

 the acquirement of such evidence if it ever be forthcoming. It 

 appears to me, however, to be well to raise such a question, so 

 that our astronomical spectroscopists may be on the outlook for 

 some evidence of the cause of so very remarkable a defective 

 condition in the light-reflecting power of Mercury to which I 

 have thus endeavoured to direct attention." — On the water of 

 Thirlmere, by Harry Grimshaw, F.C. S., and Clifford Grimshaw. 



Paris 



Academy of Sciences, October 28. — M. Fizeau in the 

 chair. — M. De la Gourmerie read a note on the works of the 

 late M. Bienayme. — The following papers were also read : — On 

 the decomposition of hydracids by metals, by M. Berthelot. 

 The heat of fonnation of gaseous chlorhydric acid from its 

 elements is surpassed by that of all anhydrous chlorides, even 

 chlorides of lead, copper, mercury, and silver ; gold is the only 

 exception among ordinary metals. The inference that all these 

 metals, except gold, must decompose chlorhydric gas with 

 liberation of hydrogen, is confirmed by experiment. Platina and 

 palladium, also, their chlorides having low heats of formation 

 and little stability, did -not decompose chlorhydric gas up to 

 550°. — On Vice-Admiral Cloue's " Pilote de Terre Neuve," by 

 M. Faye. — On the state in which carbonic acid exists in the 

 blood and the tissues, by M. Bert. The escape of carbonic 

 acid during the respiratory act requires a dissociation of 

 the super-carbonised salts of the blood. These salts were 

 saturated with carbonic acid neither in the arterial nor 

 the venous blood, nor in the tissues. The life of the 

 anatomical elements can only be maintained in presence 

 of carbonic acid in the state of combination. When the alkalis 

 are saturated, and this gas appears in excess in the state of 

 simple solution it rapidly causes death. — Influence of the 

 nervous system on the phenomena of absorption, by M, Moreau. 

 He attached to the dorsal fins of fishes that had swimming 

 bladders a small glass balloon, lighter than the water, and in a 

 few hours the volume of the fish had diminished through absorp- 

 tion of a part of the air contained in the bladder. When a piece 

 of metal was substituted for the balloon, the volume of the fish 

 increased. There is thus a sensation of thrust upwards or 

 downwards, and it is under influence of the former that absorption 

 of air in the bladder takes place, probably through a reflex action. 

 — On decipium, a new metal of samarskite, by M. Delafontaine. 

 In the samarskite of North Carolina he finds yttria, erbine, terbine, 

 Philippine (yellow (PpO), equiv. about 90 ; characteristic absorp- 

 tion band about 449 in A), decipine (white (DpO), equiv. about 

 122, band 416) ; thorine and oxides of didymium and cerium. 

 The equivalents of the metals in some of these earths are shown 



to present interesting numerical relations. Decipium is so called 

 from decipiens, deceiving. The didymium of cerite is probably 

 a mixture of several bodies, by M. Delafontaine. This is based 

 on spectral observations. — Reply to a recent communication by 

 M. Him, on a gyroscopic apparatus, by M. Gruey. — Classi- 

 fication of double stars, by M. Flammarion. Of the 11, coo 

 double or multiple stars discovered, he finds there are only 819 

 that give certain indications of a relative motion of the com- 

 ponents. These groups are divided into 731 doubles, 73 triples, 

 12 quadruples, 2 quintuples, and I sextuple, in all 1,745 stars 

 variously associated. Of these couples in motion 558 have 

 been found with orbital systems, and 316 whose components 

 have been connected merely by the chance of celestial per- 

 spectives and form optical groups. In the orbital systems 

 there is a preponderance of retrograde motion from north 

 to south by west (Several other facts are given.) — On 

 the integration of the equation (i) Ay'^ -^ By^ + Cy"^ -(- 

 Dy' -f Ey + F — O, hy M. Alexeeff. — On involution in curves 

 of n degree, by M. Serret. — Remarks on two integrals obtained 

 by Lame in the analytical theory of heat, by M. Escary. — Re- 

 ply to an observation of M. Boltzmann, by M. Levy.— On the 

 magnetisation of tubes of steel, by M. Gaugain. When a sys- 

 tem formed of two parts having different coercive forces is sub- 

 jected to action of a weak current, the part having the least coer- 

 cive force is always that which takes the strongest magnetisation- 

 (whichever its position, tube, or core). — On a telephone call, by-' 

 M. Perrodon. This consists in connecting a Ruhmkorff coil- 

 with the plate of the telephone, so as to get a loud continuous - 

 sound. — On the transformation of valerylene] into terpilene, by^ 

 M. Bouchardat. — Artificial reproduction of melanochroite, by 

 M. Meunier. This is by keeping fragments of galena in dilute 

 aqueous solution of bichromate of potash. — On the elimination ' 

 of salicylate of soda, and the action of this salt on the heart, by - 

 MM. Blanchier and Bochefontaine. It stimulates various secre- 

 tions, notably the salivary. In man it is at once expelled by 

 the kidneys (appearing in the urine in 20 mm.); in the dog it 

 appears both in the urine and the saliva, also in the bile and 

 pancreatic fluid. The hypersecretion of saliva is due to action 

 of the salicylate on the grey substance of the central nervoi; 

 system. In strong doses, the salt stops the heart in diastole. — 

 On parthenogenesis in bees, by M. Sanson. 



CONTENTS 



Pa 



Sanitary Engineering , . . 



The Naples Zoological Station 



OwR Book Shelf :— 



Petersen's " Theorie der algebraischen Glelchungeti " 



Wilson's " Botany of Three Historical Records, Pharaoh's Dream, 



The Sower, and the King's Measure " 



Simmonds' "Commercial Products of the Sea; or. Marine Ccntri- 



butions to Food, Industry, and Art " 



Letters to the Editor:— 



A Question raised by the observed absence of an Atmosphere in the 



Moon. — S. ToLVER Preston 



Remarkable Local Colour- Variation in Lizards. — ^Alfred R. Wal- 

 lace and Baron de Basterot 



Termites kept in Captivity by Ants. — Henry O. Forces .... 

 Colour-Blindness. — Clementina Black ; Edmu.vd McClure . . 



Carrier-Pigeons. — Thomas Stevenson, C.E 



Globular Lightning — Charlotte Hare 



Speaking-Trumpets. — Wm. Chappell 



Toughened Glass. — G. C. Druce 



Pottery at the Paris Exaibition 



Sun-Spots, Atmospheric Pressure, and the Sun's [Heat. By 



John Allan Broun, F.R.S 



The Size OF THE Tiger. By Sir'J. Fayrer, F.R.S 



The TELErHONE, its History, and its Recent Improvements, II. 



By Prof. W. F. Barrett (With Illustrations) 



Our Astronomical Column : — 



The Late Solar Eclipse at Watson's Station 



Calculation of Excentric Anomalies 



The Minor Planets 



Geooravmical Notes 



The Werdermann Electric Light 



Notes 



On the Vertical Distribution of the Light from Lighthouses 

 placed at High Elevations above the Sea-Level. By T. 



Stevenson, C.E. . . 



Medical Endowments at Oxford 



On the Thermal Phenomena Produced by the Passage of Elec- 

 tricity through Rarefied Gases. By Dr. Naccari and M. 



Bbllati 



Notes fro.m New Zealand 



University and Educational Intelligence 



Scientific Serials 



Societies and Academies 



