July 25, 1889] 



NA TURE 



311 



of this article the author has completed the survey of all the 

 species known to him from the Oleneilus (Lower Cambrian) zone 

 in North America. From a general comparison of this zone 

 with the Ordovician the superiority of the latter in number of 

 species, genera, and families becomes at once apparent. But 

 when the comparison is extended to class characters, the disparity 

 is much reduced, and it is made evident that the evolution of life 

 between the two epochs has been in the direction of differentiating 

 the class types that existed in the earlier fauna. It cannot be 

 asserted that the Oleneilus fauna of Europe and North America 

 was contemporaneous, although its relations to the succeeding 

 Middle and Upper Cambrian and Ordovician is everywhere 

 essentially the same, the Oleneilus being the basal fauna wherever 

 it has been found. — On allotropic forms of silver (continued), by 

 M. Carey Lea. The properties are given of the two already 

 described insoluble forms of allotropic silver, which differ from 

 normal silver especially in their sensitiveness to light, their 

 brittleness and specific gravities (9*58 and 851, the normal being 

 105). — The peridotile of Pike ("ounty, Arkansas : Part L, 

 description and general relations, by John C. ihanner ; Part IL, 

 microscopic study, by Richard N. Brackett. Though srriall in 

 extent, the exposure of peridotile occurring near Murfreesboro, 

 Pike County, is geologically important, as offering a clue to the 

 time and character of the disturbing influences which about the 

 close of the Cretaceous sank the greater part of Arkansas and 

 other contiguous regions beneath the ocean. It is also interesting 

 as being the third reported occurrence of picrite-porphyry in the 

 United Slates. Its position and topographic fer^tures are shown 

 in the accompanying map. — Papers are contributed by T. M. 

 Chatard, on urao, shown to be the true natural form of sodium 

 carbonate ; by Edward F. Ayres, on the crystallization of trona 

 (urao), from Borax Lake, California ; by G. P". Kunz, on 

 fluorite, amber, opal, and diamond ; and by O. C. Marsh, on 

 the discovery of Cretaceous Mammalia by J. B. Plalcher in the 

 Laramie formation of Dakota and Wyoming. There is also a 

 reprint of Mr. James Croll's paper in the Quarterly Journal of 

 the London Geological Society for May 1889, on prevailing mis- 

 conceptions regarding the evidence of former glacial periods. 



In the Amcritan Alcteorological yoiirnal for June, Mr. A. L. 

 Rotch contributes an interesting article on the organization of 

 the meteorological service in Belgium. The Royal Observatory 

 was established in 1826, and deals with astronomy, meteorology, 

 and magnetism. The present net-work of stations consists of 

 three Observatories (including Liege, which is independent of 

 the Royal Observatory), fifty stations of the second order, and 

 •about 120 rain-stations. Instruments are generally lent, but 

 the observers are volunteers. The most notable instrument in 

 use is the electrical meteorograph, invente<l by F. van Ryssel- 

 berghe, which engraves its indications on metal plates, from 

 which copies can be printed. The recording apparatus can 

 work at any distance from the meteorological instruments. — 

 Lieutenant J. P. Finley gives a chronological table of tornadoes 

 in the State of Michigan for sixty-six years ending i888, with a 

 chart. The total number of storms observed was seventy-six ; 

 the year of greatest frequency, 1886 — eighteen storms. The 

 greatest monthly frequency was in May and September, and the 

 prevailing direction of movement, north-east. The publication 

 of these statistics is the more valuable, as we learn from another 

 part of the Joiirnal that recent restrictions on the publications of 

 the Chief Signal Office prevent it from issuing Lieutenant Finley's 

 tornado charts. — Prof. F. Waldo has a review on some import- 

 ant tornado literatuie. The author points out where the most 

 important discussions of the subject can be found, and calls 

 attention to soiiie particular points therein. Most of the au- 

 thentic accounts between 1835-50 are contained in Silliman s 

 yournal, since which time most prominent meteorologists have 

 investigated the subject, especially Loomis and Reye. — Mr. W. 

 W. Harringion contributes an article on the whirlpool theory 

 of storms. The object of the paper is to lay before the readers 

 <rf the yournal the views of M. Faye, as formulated in his 

 work, "Les Tempeies" (1887), which work was reviewed in 

 our columns. Mr. Harrington offers no opinion upon the theory 

 itself, or upon the criticisms of the same. 



SOCIETIES AND ACADEMIES. 



Paris. 



Academy of Scien:es, July 15.— M. Hermite in the chair. 



— Observations of the sijiall planets and of Barnard's comet 



mide at the great meridian instrument of the Paris Observatory 



during the second half of the year 1888, by M. Mouchez.— 



Thermic researches on the iiomeric nitric camphors and on cyanic 

 camphor, by MM. Berthelot and P. Petit. From these researches 

 it appears that, between Cazeneuve's two isomerous nitric cam- 

 phors, answering to the formula CooHjgNOc there exists the same 

 difference as between a nitrified body and a nitric ether, or any 

 substance of analogous function ; further, that nitro-phenol cam- 

 phor must be less explosive than the corresponding isomerous 

 body. For cyanic camphor the mean heat of combustion has 

 been determined at 8445-3 calories. — On the decomposition of 

 the sulpho-conjugated acids by means of phosphoric acid, by 

 MM. C. Friedel and J. M. Crafts. On recently resuming their 

 study of this question the authors have found that owing to the 

 secondary reactions the decomposition of the acids in question 

 in presence of sulphuric acid does not usually yield all the hydro- 

 carburets contained in them. But the complete decomposition 

 may be effected by mixing the sodium or potassium salt of a 

 sulphonic acid with a considerable excess of concentrated phos- 

 phoric acid at a temperature of 60° Baume. — On the studies in 

 atmospheric micrography undertaken at the Imperial Observatory 

 of Rio de Janeiro, by M. L. Cruls. Considerable interest 

 attaches to these researches, made in a tropical region and in the 

 immediate vicinity of a large city frequently visited by epidemics. 

 Some of the atmospheric particles, obtained in the usual way, 

 have been photographed M. Morize, of the Rio Observatory, 

 and enlarged by 150, 500, and 1000 diameters. In order to 

 collect sufficient data for comparative purposes, M. Cruls has 

 been authorized by the Brazilian Government to organize a special 

 laboratory to carry out a systematic series of microscopic studies 

 on the site that has been chosen for the construction of a branch 

 of the Rio Observatory. — Observations of Barnard's comet (June 

 23, 1889) made at the Observatory of Algiers with the o'50 

 metre telescope, by MM. Trepied and Sy, on July i nnd 5. 

 — On the Brownian movement, by M. Gouy. The author has 

 studied this phenomenon under a great variety of conditions and 

 with diverse kinds of liquids and particles. It results from his 

 observations that this movement is produced with particles of 

 every description, its intensity diminishing in direct ratio to 

 the viscosity of the fluid and the size of the particles ; also 

 that it is a perfectly regular phenomenon, produced at a con- 

 slant temperature and independently of all external influences. 

 Thousands of particles have been examined, and in no single 

 case has any particle in suspension failed to present the 

 usual movement, with its nornial intensity regularly decreasing 

 with the increased size, but not with different kinds of particles, 

 the solid, liquid, and gaseous all behaving much alike under like 

 conditions. This fact clearly shows that the cause of the 

 phenomenon is to be sought, not in the bodies themselves, but 

 in the fluid element, whose internal movement they serve to 

 render visible. Hence the Brownian movement alone of all 

 physical phenomena reveals to the eye a constant state of in- 

 ternal agitation in bodies independently of all outward influences. 

 The fact here established will naturally be associated with current 

 kinetic hypolhese-, and may perhaps be regarded as a faint and 

 remote result of calorific molecular movements. In this pheno- 

 menon the velocities may be estimated at some microns per 

 second, or about 1/100,000,000 of those attributed to molecular 

 movement. — On the electrolysis of distilled water, by M. E. 

 Duter. These experiments, and especially that conducted with 

 aluminium, point to the inference that there are formed at the 

 negative pole metallic hydrides, which are destroyed by the water 

 with formation of an oxide and liberation of hydrogen. — On the 

 ammonio-cobaltic molybdales, tungstates, and vanadates ; separa- 

 tion of cobalt and nickel, and of the cobaltous and cobaltic 

 salts, by Adolphe Carnot. The ammonio-cobaltic salts differ 

 in many respects from the corresponding salts of the cobalt and 

 nickel protoxides. But their respective characters are not, as a 

 rule, sufficiently marked to »serve to discriminate and separate 

 these salts. M. Carnot, however, now finds that this advantage 

 is presented by the molybdales, tungstates, and vanadates. In 

 the present paper he deals with the molybdales alone. — On the 

 reactions of oils with nitrate of silver, by M. Raoul BruUe, 

 During his researches on the character oi diffeient oils, the author 

 has been led to employ the nitrate of silver as a reagent. The 

 results present remarkable differences in the case of olive, cotton, 

 linseed, colza, and other vegetable oils. — On the egg of the 

 i-ardine, by M. Georges Pouchet. The author's observations 

 show that the sardine de roi^ue (the small sardine of commerce) 

 is a young fish not yet arrived at maturity, and presenting the 

 greatest irregularity in the development both of the ovaries and 

 the ovules ; nor, as a rule, is the size any clue to its state of 

 development. 



