144 



NATURE 



. \June%, 1882 



frog tadpoles by describing the three remaining periods into 

 which their life-history may be divided. 



Berlin 



Physical Society, May 12.— Prof. Du Bois-Reymond in 

 the chair. — Dr. Herz spoke on hardness. The methods hitherto 

 used to determine the hardness of bodies have all been merely 

 comparative estimates, e.g. in mineralogy it has been stated by 

 what other substances the material in question is scratched, and 

 what it can scratch, and so its position in the scale of hardness is 

 shown to be between these others. Or it has been ascertained 

 by some physicists to what depth in the substance a steel cone is 

 pressed by a given force, and this depth gives a measure of the 

 hardness, llerr Herz has sought a more absolute method ; and 

 he has confined himself, on account of the complexity of the 

 question, to consideration of isotropic elastic substances. In 

 these the hardness may be determined by the pressure which 

 must be exerted on a round surface, to exceed, by the deformation 

 produced, the limit of elasticity. In the case of plate-glass, e.%. 

 it was found by experiment, that at a pressure of 136 kg. per 

 square mm., the limit was passed, and a circular crack was 

 produced ; 136, accordingly, expresses the degree of hardness of 

 the glass. Every isotropic body which has exceeded its limit of 

 elasticity under greater or less pressure, is, respectively, harder or 

 less bard. The advantage of this method lies in the fact that no 

 second substance is needed, but only two balls or lenses of the 

 substance examined. — Prof. Christiani then showed, as samples 

 of a new method of preservation a series of organic bodies coated 

 galvanoplastically ; a mulberry leaf, a crab, a butterfly, a beetle, 

 the brain of a rabbit, a rosebud, and other objects, were silver-, 

 gold-, or copper-plated, and showed all details of their outer 

 form, down to the finest shadings, very well preserved. As to 

 the process (which is patented by the inventor), it was stated 

 that the objects to be preserved, being put, living or dead, into 

 a solution of silver nitrate in alcohol, then dried, and treated 

 with sulphuretted and phosphuretted hydrogen, form good con- 

 ductors, which, brought in the usual way into the galvanoplastic 

 bath, can be coated with any desired thickness of a metallic 

 deposit. 



GOTTINGEN 



Royal Society of Sciences, January 7. — Contribution to 

 the theory of surfaces, with special reference to minimal surfaces, 

 by A. Enneper. 



February 4. — Report on the Polyclinic for ear diseases, by 

 K. Burkner. — Completion of Steiner's elementary geometrical 

 proofs of the proposition that the circle has a greater surface- 

 content than any other plane figure of equal circumference, by 

 F. Edler. 



March 4. — On functions which remain unchanged by linear 

 substitutions, by L. Fuchs. — Measurement of the earth's mag- 

 netic horizontal intensity by means of bifilar suspension of a 

 magnet, by F. Kohlrausch. — Contribution to the theory of sur- 

 faces, cic. (continued), by A. Enneper.— On cryolith, pachno- 

 lith, and thomsonolith, by C. Klein. — Communications on 

 Giordano Bruno, by P. de Lagarde.— Report on Beneke prize. 



Parts 

 Academy of Sciences, May 29.— M. Blanchardin the chair. 

 — The following papers were read : — Separation of gallium, by 

 M. I.ecoq de Boisbaudran. — On the cycle of reasoning ; its use 

 for formulating and strengthening the fundamental hypotheses 

 and propositions of all science ; application to mechanic-, by M. 

 Ledieu. The cycle includes four operations : (1) observation 

 and, if necessary, experimentation a priori ; (2) induction ; (3) 

 deduction ; (4) experimentation and, at least, observation a pos- 

 teriori. A fundamental hypothesis or law is more or less 

 rational when, on submitting it to the cycle, one can more or 

 less close this cycle. The author illustrates this. — Report on a 

 memoir of M. Bouquet de la Grye entitled, " Study on Waves 

 of Long Period in the Phenomena of Tides." In this memoir 

 the author extends the work of Laplace. It is also proved, inter 

 alia, that the greatest elevation of the water at Brest occurs, not 

 with west but with south winds. The density of the water is 

 found to explain the unexpected fact revealed by Bourdaloue, 

 that the mean level of the ocean at Brest is higher by 1 '02 m. 

 than that of the Mediterranean at Marseilles. From 1834 to 

 1S7S the mean level of the ocean has sunk, at Brest, or the 

 ground has risen (the fact subsists, after allowing for variation of 

 temperature and saltness). The relative rise of ground has been 



about I mm. a year. — Measurement of the volume of blood con- 

 tained in the system of a live mammal, by MM. Grehant and 

 Quinquaud . The method used depends on carbonic oxide giving an 

 oxycarbonised haemoglobin, a more fixed combination than oxy- 

 genated haemoglobin (the carbonic oxide being substituted for the 

 oxygen volume for volume). An animal is made to breathe gas 

 containing a known amount of CO. The volume of CO remaining 

 is noted, say, in a quarter of an hour, and this gives the amount 

 fixed. On the other hand, the blood is analysed to find the CO 

 fixed in a given volume. In this way it was found that the total 

 weight of blood is between I-I2lh and '-13th of the body- 

 weight. In the normal state there are no great variations. — 

 Obervations to serve in the study of phylloxera, by M. Boiteau. 

 — On a proposition relative to linear equations, by M. Darboux. 

 — Demonstration of a theorem relative to the function E (.<), by 

 M. Bouniakowski. — Two means of having v in the game of head 

 or tail, by M. Barbier. — On a mode of transformation of figures 

 in space, by M. Vanecek. — On a potential with four variables, 

 which renders almost intuitive the integration of the equation of 

 sound, and the demonstration of the formula of Poisson concern- 

 ing the inverse potential with three variables, by M. Boussinesq. 

 — On the actinic transparence of optical glasses, by M. de Char- 

 donnet. A species of glass only allows passage (even with thin 

 plates, and with long exposure) to wave-lengths exceeding a 

 certain minimum, characteristic of the material. Another cha- 

 racteristic is the thickness beyond which elective absorption 

 diminishes no further. With these limits, the shortening of 

 the spectrum seems sensibly proportional to the thickness f th* 

 medium. The actinic absorption (measuring the shortening 

 of the spectrum in the scale of wave-lengths) for a given 

 optical system is comprised between the absorption of the 

 least transparent glass and the sum of proportional shorten- 

 ings due to all the glasses of the apparatus. — Action 

 of sulphydrate of ammonia on sulphide of tin, by M. Ditte. — 

 Influence of the tension of sulphuretted hydrogen in presence of 

 a neutral solution of sulphate of nickel, by M. Baubigny. — On 

 the transformations of cuproso-cupric sulphites, by M. Etard. — 

 Determination of glycerine in fatty matters, by M. David. He 

 saponifies 100 gr. of tallow with baryta. — On the ligneous for- 

 mations produced in the pith of cuttings, by M. Prillieux. — On 

 the true situation of the mouth of the Shire, and on the canal of 

 communication connecting this river with the Zambesi, by M. 

 Guyot. Correcting the notion that the Shire, after entering the 

 lake of Lydia, resumes its course and joins the Zambesi ne ir the 

 foot of Chamouara, be represents that the lake is really connected 

 with the Zambesi by a canal called Zio-Zio ; running first W.S.VY. 

 to E. N.E. , then nearly east, which conveys wa.er from the 

 Zambesi and is a larger feeder of the lake than the Shire (the 

 latter at its entrance into the lake is only about 670 feet wide 

 and 3 to 4 feet deep, with little current). 



CONTENTS Page 



Ants, Bees, And Wasps. By Dr. George J. Romanes, F.R.S. . 121 

 Our Book Shelf:— 



Aldis's "Great Giant Arithmos" .... 123 



Lock's " Treatise on Elementary Trigonometry ; " Vyvyan's 



'* Introduction to Plane Trigonometry " 124 



Smith's " Elementary Treatise on Conic Sections' - 124 



Letters to the Editor : — 



The Darwin Memorial. — J. T. Cunningham 124 



Comet a 1S82.— A. Percy Smith ; F. T. Mott 124 



Meteors.— Rev. S. J. Perky. F. R.S. ; Rev. John HOSKYH - 



Abrahall 124 



Earth-Tremors in Japan. — John Milne 125 



Limulus.— Dr. H. A. Hagbn 126 



The Utilisation of Ants in Horticulture.— Prof. C V. Riley . . 126 



Aurora Australis. — T. H. Potts 136 



" Cuprous Chloride Cell."— A. P. Laurie 126 



Physico-Chemical Lecture Experiments. — Leigh Clifford . . . 126 



Curs and Circles 126 



The Eclipse Expedition 129 



Aurora in Greenland 1:0 



Illustrations of Nbw or Rare Animals in the Zoological 



Society's Living Collection. VIII. {With Illustrations) ... 131 



Mr. Siroh's Vibratory Experiments 134 



Notes 135 



Our Astronomical Column : — 



The Comet (1882 a) .37 



The Transit of Mercury, 1881, November S 137 



.!! Planets 137 



1 jba Zones 137 



Chemical Notes 137 



Physical Notes 13S 



Grogkaphical Notes 139 



The Royal Oksfrvatory 140 



University and Educational Intelligence 141 



Societies and Academies 142 



