Jan. 2, 1890] 



NATURE 



215 



obscured for a few minutes by a star of the tenth or eleventh 

 magnitude. — Determination of the difference of longitude be- 

 tween Paris and Leyden, by M. Bassot. This international 

 operation, executed by MM. Van de Sande Bakhuyzen and 

 Bassot, presents a special geodetic interest, Leyden being the 

 northernmost station of the meridian of Sedan which now passes 

 through Belgium far into the Netherlands. From the observa- 

 tions the difference of longitude between Paris and Leyden 

 appears to be 8m. 35*6025., with probable error ± O'Oiis., 

 which, reduced to the official meridians, gives 8m. 35 '2 1 3s. — 

 On the degree of accuracy attained by thermometers in the 

 measurement of temperatures, by M. Ch. Ed. Guillaume. On 

 presenting to the Academy his '* Traite pratique de la Thermo- 

 mt'trie de precision," the author took occasion to reply to M. 

 Renou's recent remarks on the accuracy of the mercury ther- 

 mometer. Reviewing the whole question, and comparing the 

 opinions and experiences of the most distinguished physicists 

 during late years, M. Guillaume considers it placed beyond 

 doubt that mercury thermometers with glass of varying qualities 

 yield varying results. But these differences, formerly supposed 

 to be fortuitous, are now known to be systematic, so that any 

 number of instruments giving identical results may be constructed 

 by a judicious selection of glass and careful manipulation. 

 — On /8-inosite, by M. Maquenne. In a previous note 

 {Compfes rendus, vol. cix. p. 812) the author showed that 

 pinite may be decomposed into a molecule of methyl iodide and 

 a molecule of a new sugar called by him i8-inosite. The analysis 

 cif these two bodies leading to identical results, he inferred that 

 they were isomerous, presenting relations of the same order as 

 those existing between the two known hexachlorides of benzine. 

 This hypothesis has been fully confirmed by his further study of 

 ;3-inosite, communicated in the present memoir. — On a new 

 class of diacetones, by MM. A. Behal and V. Auger. The 

 authors have already shown that the chlorides of malonyl, 

 methylmalonyl, and ethylmalonyl react on the aromatic car- 

 burets, yielding diacetones, /8,R— CO— CHX— CO— R. They 

 have also determined the formation of compounds having the 

 characteristic property of yielding with the alkalies and alkaline 

 carbonates blood-red solutions. A further series of researches 

 has now enabled them to prepare several of these compounds in 

 large quantities, and thus study their constitution as here de- 

 scribed. The best results were yielded by metaxylene and the 

 chloride of ethylmalonyl. — Optical properties of the polychroic 

 aureolas present in certain minerals, by M. A. Michel Levy. 

 This curious phenomenon is traced mainly to the presence of 

 small crystals of zircon widely disseminated throughout granitic 

 and other rocks. In some cases it may also be due to the 

 presence of dumortierite and allanite. These aureoles offer an 

 interesting example of a simultaneous modification of birefraction 

 and polychroism, a modification, however, which is not per- 

 manent, or at least which may disappear, without involving any 

 change in the properties of the mineral itself. — Analysis of the 

 Mighei meteorite, by M. Stanislas Meunier. This meteorite, 

 which fell on June 9, 1889, at Mighei, in Russia, yielded be- 

 sides the usual constituents, a new element, which M. Meunier 

 has not yet succeeded in identifying. — Papers were contributed 

 by M. Y. Wada, on the earthquake of July 28 at Kiushu Island, 

 Japan ; by M. Ch. Contejean, on the circulation of the blood in 

 mammals at the moment of birth ; by M. Ferre, on the semeio- 

 logic and pathologic study of rabies ; and by Messrs. Woodhead 

 and Cartwright Wood, on the antidotic action exercised by 

 the pyocyanic liquids on the development of the anthracite 

 disease. 



Berlin. 



Meteorological Society, Dec. 3, 1889.— Dr. Vettin, Presi- 

 dent, in the chair. —Dr. Kremser spoke on the frequency of 

 occurrence of mist, a subject whose investigation he had recently 

 undertaken. Up to the present time the material derived from 

 observation is extremely scanty, as shown by the extremely 

 divergent mean values obtained for different places in close 

 proximity to each other, as, for instance, Hamburg and Altona, 

 or even different parts of the one city, Berlin. It seems scarcely 

 possible to attribute the differences to local conditipns in all 

 cases, for the mean annual values resulting from the observations 

 of different observers in one and the same place show an equally 

 striking discordancy. This is undoubtedly due to the want of 

 suitable units for estimating and measuring mists. From the 

 above it follows that it is impossible to determine any secular 

 changes on the basis of existing observations, although the yearly 



variations may be. By comparisons based on a long series of 

 observations, it appeared that a series extending over ten years 

 suffices to give a reliable monthly mean. From this it appears 

 that at most stations the maximal amount of mist occurs in the 

 months of November and December, the maximum occurring in 

 November in the eastern provinces of Prussia, and falling pro- 

 gressively later the further the stations lie towards the west. 

 On the coasts of the North Sea and on the adjacent islands the 

 maximum is observed in January, while it occurs on mountains 

 as early as September and October. At the latter stations the 

 minimum is met with as early as May, and is progressively 

 later (June and July) at the other stations according to the 

 lateness of the maximum. On the islands, as, for instance, 

 Heligoland, the minimum does not occur before September 

 or October. As a general rule, 70 per cent, falls in autumn 

 and winter, 20 per cent, in spring, and 10 per cent, in 

 summer. The amplitude of the yearly differences is greatest 

 on the plains and least on mountains. The number of 

 days on which mist occurs is greatest at mountain stations, 

 amounting on the average to 200 per annum, falling in the low 

 lands to as few as 40 or less. The material at hand for deter- 

 mining the variations in the amount of mist per diem was ex- 

 tremely scanty ; still it was possible to make out that, in winter, 

 mist is most frequent in the morning, diminishing considerably 

 towards midday, and being in the evening at times as frequent 

 as at midday, at times somewhat more frequent. In summer, 

 mist is observed only in the morning, and then disappears com- 

 pletely. In the discussion which followed the above communi- 

 cation it was pointed out how essential it is to distinguish 

 between clouds and mist, as also many other factors, such as the 

 frequency of purely local mists, the absence of wind, the diffi- 

 culty of determining the density of mists, the differences of alti- 

 tude, &c. — Dr. Sprung spoke on some new self-recording appa- 

 ratus of various kinds made by Richard of Paris, and described 

 fully his actinometer and anemocinometer. 



Physical Society, Dec. 6, 1889. — Prof- Kundt, President, 

 in the chair. — Prof. Planck spoke on the development of elec- 

 tricity and heat in dilute electrolytic solutions. From the 

 experiments of Kohlrausch and Hittorf, and the theoretical 

 considerations of Van t' Hoff, Arrhenius, and Nernst, all that 

 takes place in dilute electrolytic solutions during the passage of 

 a current is very accurately known, especially in the cases where 

 the solution is very dilute and the electrolyte is very uniformly 

 distributed in it. It has become possible to subject the occur- 

 rences in electrolytic solutions to mathematical investigation, 

 owing to the existing conceptions of the osmotic pressure 

 in such solutions, of the more or less complete dissociation 

 of the electrolyte when in dilute solution, of the applicability 

 of the gaseous laws to such solutions, and owing to the experi- 

 mental determination of the rate at which the ions travel. The 

 speaker had submitted the general case, in which the solution is 

 not quite uniform, to a mathematical analysis, and deduced the 

 formulae which represent that which is taking place in each unit 

 of volume of the highly diluted solutions in which dissociation is 

 complete. These formulae correspond exactly to those arrived 

 at by Nernst for the development of electricity. Up to the present^ 

 time the thermal phenomena in dilute electrolytic solutions 

 have not been fully dealt with. The speaker showed that heat 

 is the most important form of energy existing in the solution. It 

 is only possible to arrive at a complete understanding of the heat 

 production if, when drawing parallels between dilute solutions 

 and gases, a further step is taken, and it is assumed that just as 

 gases become warmer by compression and colder by a fall of 

 pressure, so also heat is developed in electrolytic solutions when 

 the ions are increased in number, and disappears when they are 

 diminished per unit of volume. Hence the mere diffusive pro- 

 cesses in an electrolytic solution whose composition is not 

 uniform must develop an osmotic heat, which makes its appear- 

 ance, and can be calculated in the absence of any electrical current. 

 This osmotic heat must be taken into account, along with the 

 two already known sources of heat production, during the pas- 

 sage of an electric current through a solution, before it is possible 

 to calculate all the relationships of energy in a dilute, non- 

 uniform, electrolytic solution during the passage of a current 

 through it. — The President exhibited the air-pump constructed 

 by Otto von Guericke in 1675, which had recently been acquired 

 by the Physical Society. This pump is still in a thoroughly 

 workable condition, with the exception of the glass vessel, which 

 has been renewed. The pressure in this receiver could be re- 

 duced to 20 mm. of mercury, by means of the pump. The 



