Iher

tracts from Fischer, finds no place in it, though here and there an isolated fact is planted side by side with some crude observation of the first quarter of this century. ing's classification, the most pregnant and suggestive (if not the most successful) attempt in many years, is not even mentioned. There is shown no grasp of the subject; and, on contested questions of importance, the treatment recalls a man in a menagerie poking up the animals through the bars. Errors of fact and of the types could be cited in abundance but it is not necessary to descend to small details; the real fault is with the architecture, not with the bricks.

THE PARIS METEORITES.

Guide dans la collection de météorites du Muséum d'histoire naturelle. Paris, Masson. 1882. 40 p. 8°. THIS little work of some forty pages is valuable as giving in brief the results of the extended studies upon meteorites by Prof. A. Daubrée and his assistant Dr. Stanislas Meunier. Besides furnishing a catalogue of all the specimens to be found in the collection, three hundred and six in number, it discusses the origin, characters, classification, etc., of meteorites. These are regarded as having a common origin, and possessing types corresponding to rocks and structures of terrestrial origin, i.e., to lavas, dunite, lherzolite. serpentine, breccias, pumice, metallic veins, metamorphic rocks, etc. The classification is one which, in its simpler divisions, has been well received, but in the minor subdivisions is but little known; hence it is a matter of interest to place this classification in its latest phase before our readers.

cates when they are present. The subdivisions are named from the localities at which the specimen chosen as a type happened to fall. It is unfortunate that the bibliographical index, professing to give the principal works relating to meteorites. should be so very imperfect, giving only eight works and papers, omitting such as the classical publications of Chladni in 1819, Schreibers, and Partsch, and the more recent ones of G. Rose, Shepard, Clark, Harris, Rammelsberg, Kesselmeyer, Phipson, Lawrence Smith, and others.

EARLY ORIENTAL HISTORY. Histoire des anciens peuples de l'orient; par Louis MÉNARD. Paris, 1882. 468 p. 8°.

THIS work contains the outlines of Egyptian, of Assyrio-Babylonian, and of Israelitish history. Parts i. and ii. are profusely illustrated from the monuments. Part ii. (Assyria and Babylonia) covers 102 pages, and discusses in five chapters the region of the Tigris and Euphrates, the primitive times, the Sargonidae, the new Chaldean empire, the monuments, religion, manners, and customs. The author tells in a pleasing way what he knows of these topics; but, unfortunately, he is not a student of Assyriology, nor has he informed himself as to the latest results of Assyrian study. His authorities are the Old Testament, Berosus, and the classic writers and the older

name

generation of explorers and decipherers (Botta, Layard, Rawlinson, Hincks). Of the younger generation, with one or two exceptions, he knows absolutely nothing (Smith and Sayce in England; Halévy, Pognon, and Guyard in France; Schrader, Delitzsch, and others in Germany). Hence he quotes (p. 261) from Berosus the Chaldean legend of the deluge, and points out its similarity to the biblical account, without even mentioning the cuneiform deluge story discovered by the lamented George Smith. On p. 262 he tells us that the 'Babylon' seems to meangate of god.' Certainly this meaning is above possible doubt. He informs us (pp. 262, 263) that the people of Accad and Sumer are of different race; the former being Cushites, and speaking a language approaching the Semitic tongue, the latter being of the Scythic or Turanian stock. He has evidently never heard of Paul Haupt, who has shown that the peoples of Sumer and Accad spoke the same language with dialectical differences, a language utterly unlike any Semitic tongue. He says (p. 273) that 1112 B.C. is the oldest date which can be established for the history of Assyria. He should

have added, that, before this time, there is a long line of Assyrian kings, for many of whom the date can be fixed at least approximately. The author informs us that it has been supposed that the person kissing the foot of Shalmaneser on the black obelisk may be Jehu, king of Israel, whose name, he tells us, is mentioned in the inscription (p. 278). The Israelitish face of the kneeling figure, and the fact that the name Jehu (Assyr., Ya-u-a mar Hu-um-ri-i = Jehu the son of Omri) stands immediately above the picture, ought to allow of no doubt in the matter. The statement (p. 285) that Shalmaneser, the predecessor of Sargon, is not once mentioned in the cuneiform inscriptions, is incorrect; for he is named in the Eponym canon (III. R. 1. col. V. 1), and at least one other time (cf. George Smith: The Assyrian canon, p. 84). The

1 R. is the usual way of representing the great collection of Assyrian texts called The cuneiform inscriptions of Western Asia,' of which Sir Henry Rawlinson is editor. The Roman numeral preceding indicates the volume; the following numerals refer to the page, column, and line.

author gives the conflicting opinions of Lenormant and Maspéro, as to the fate of the rebellious brother of Assurbanipal (p. 301). Assurbanipal's own statement is explicit to the effect that his brother was burned, though the gods are represented as having performed the work (V. R. 4. 46 ff.). It is misleading to say (p. 275) that the Assyrian kings never tried to hold by mild government their conquered provinces; for the later kings at least often bestowed favors on captive princes, not seldom replacing them on the throne. Such cases of inaccuracy and uncertainty might be multiplied. The writer knows too little of recent work in Assyriology, and does not hesitate to express his scepticism as to the way in which Assyrian students read proper names (pp. 271, 301). One who has not studied the language for himself can, of course, not yet write a history of Assyria and Babylonia. The book has the credit of brevity, and gives very well a general impression, but cannot be relied upon in detail.

ASTRONOMY.

Transit of Venus observations at Helderberg, N.Y.-Mr. R. H. Tucker, jun., of the Dudley observatory, gave a detailed account of the arrangements for, and results of, his observation of the transit of Venus, at a station established for the purpose on the Helderberg table-land, about thirteen miles westward from the city of Albany. The site chosen was the U.S. coast and geodetic survey, and the N.Y. state survey station, Helderberg; lat. 42° 37' 38, long. 74° 00 39; altitude, 1,823 feet. The cloudiness which prevented the observation of either contact at the Dudley observatory was but partial at the Helderberg station, and a satisfactory view of the second contact was realized. An estimate was also made of the time of the first contact, based upon a comparison of the phase first seen a few minutes later, with diagrams constructed in connection with preliminary practice.

The errors of the chronometers were obtained by heliotrope signals, and powder-flashes from the Dudley observatory, and by sextant observations of the sun. (Albany inst.; meeting Jan. 2.) [80 Transit of Venus observations at New Haven. Prof. H. A. Newton described his temporary mounting by which he used the eight-inch Grubb object-glass of the observatory to observe the contacts. Dr. L. Waldo referred to the preliminary drill with the Yale heliometer which the five observers and assistants with that instrument had undergone, and said that the results were extremely satisfactory. The definition was good most of the day, and the instrument and dome was manipulated quickly with no waste of time. He gave the following summary: 24 half sets of 4 pointings each, 10 whole sets of 8 pointings each, 20 single pointings on Venus for its diameter, 10 position measures at ingress, and 6 position measures at egress, with time observations of

the four contacts. Mr. Willson described an arrangement by which he had put a cast-iron cylindrical plate-holder in the eye end of the Grubb telescope, and had projected a mercury horizontal surface, together with the reticule glass lines on each of the hundred and fifty or more photographs he had reason to think would develop well. He also described a ten-foot rod caliper he had used in measuring the plate distance from the object-glass. He used a simple crown lens of about one inch and a quarter aperture, and ten feet focal length.

Mr. Sherman, through the courtesy of the scientific school, used the nine-inch equatorial, and obtained about eighty-seven sets of transits of Venus and the sun's limbs across a system of inclined lines ruled on glass. Professors Van Vleck, Lyman, Wright, and Brewer took part in the discussion following the above papers; and, after describing their own contact observations, referred to the atmosphere of Venus, and in general regarded the want of intense blackness of Venus's disc as an effect of contrast with the sun. -(Conn. acad. arts sc.; meeting Dec. 20.) [81

tends the theory of Steiner's polygons and Prof. Sylvester's theory of derivation to the case of curves of order n and deficiency p in an (n-p) flat. The extension involves the use of Abelian functions instead of elliptic functions, as in the case of a plane cubic, and is based principally upon Clifford's wellknown paper, On the classification of loci. — (Proc. Lond. math. soc., 1882.) T. C. [84 Fourier's functions.-M. Nicolas prefers to denote, by this title, the functions more commonly known as Bessel's or cylindric functions. The author studies principally the different modes of representation of these functions by definite integrals and series. A novelty is the introduction of a method of Euler's in finding the development in form of a series of the functions of the second kind. - (Annales école norm., xi., suppl., 1882.) T. c. [85 Geometry of n-dimensions. The author, M. V. Schlegel, here extends certain well-known theorems of ordinary plane and three-dimensional space geometry to a space of any number of dimensions. The paper deals only with completely limited figures, regular and irregular. A homogeneously limited figure is defined: 1°, as one in which each summit meets the same number of edges, planes, solids, etc.; 2°, as one in following any edge of which we meet the same number of edges, planes, etc. Writing 'homogeneous' instead of limited homogeneously,' we see that all plane polygons are homogeneous, etc. The author uses the methods of Grassman, and extends to hyperspace theorems concerning the triangle, quadrilateral, tetrahedron, hexahedron, and octohedron. — (Bull. soc. math. France, x., 1882.) T. C.

[86

Curves whose co-ordinates are elliptic functions. R. von Lilienthal discusses two classes of spherical curves having the following properties: The constants in the expressions for the co-ordinates, with the exception of one (which, with the modulus, is arbitrary), can be so determined that the sought curve shall lie on a sphere. The length of an arc of the curve can be given as an elliptic integral of the first kind increased by the difference of two elliptic integrals of the third kind.

For the second group of curves, the arbitrary constant can be so determined that the integral giving the length of arc shall be an elliptic integral of the first kind. It is also shown that the curves of the second kind lie on algebraical cylinders. — (Journ. reine angew. math., xciii., 1882.) T. C. [87

Applications of the theory of binary forms to elliptic functions. The author, Faà de Bruno, expresses the elliptic functions by aid of the absolute invariant, and gives a very rapidly converging series for the computation of the complete elliptic integral of the first kind. — (Amer. journ. math., 1882.) T. c. [88 Rotation of a solid body. This treats the case of rotation of a solid body about a point which is in general neither the centre of gravity of the body nor (in the case of a body of revolution) a point on the axis of revolution. The author, W. Hess of Munich, discusses the general case, and obtains several interesting theorems on making particular hypotheses as to the position of the point about which the body rotates. (Math. annalen, xx., 1882.) T. C. [89 Vibrations of an elastic sphere. Prof. H. Lamb here discusses the problem of the vibrations of an elastic solid whose dimensions are all finite. He has given several numerical calculations and diagrams, illustrating, in special cases, the results arrived at by the purely mathematical investigation. The author points out that the results of his analysis differ from the views advanced by Lamé (Théorie de l'élasticité)

as to the nature of the fundamental modes of vibration of elastic solids in general; and indicates the error in Lamé's reasoning as consisting in the tacit assumption that a wave undergoes no change of character on reflection at the bounding surface of a solid, -an assumption the incorrectness of which was previously shown by Green. -(Proc. Lond. math. soc., 1882.) T. c.

[90 Subinvariants.- An important paper by Professor Sylvester, of which, since it is not yet completed, a review will be given at a later date. - (Amer. journ. math., v., 1882.) T. C. [91

PHYSICS.

Apparent attractions and repulsions of small floating bodies. — The need of a thoroughly sound and at the same time simple popular explanation of capillary phenomena will probably make every teacher of elementary physics take up Prof. Leconte's article with interest. As he states, ordinary treatises are somewhat unsatisfactory upon this subject, even when they are not actually wrong. For instance, the in general excellent treatment of capillary action in Everett's Deschanel' handles the phenomena observed in a vacuum in a very gingerly manner, hinting at a certain mysterious pressure in the interior of liquids due to molecular action at the surface, even when such surface is plane, in order to account for the rise of liquids in fine tubes in a

vacuum.

In view of the fact that the capillary action of liquids is practically the same in a vacuum as in air, Prof. Leconte appears to be of the opinion that it is unnecessary to take account of atmospheric pressure in explaining any of these phenomena. He proposes to base his explanation upon two 'fundamental principles 1. "That in every case, whether of moistened or non-moistened bodies, there exists an adhesion between the solid and the liquid." 2. "That the capillary forces are, in any given case, inversely proportional to the radii of curvature of the meniscuses, and their resultants, directed toward the centres of concavity."

We suppose Prof. Leconte will admit, however, that although the visible phenomenon of water sustained in a capillary tube, for instance, may remain unchanged when the surface of the water is relieved of the pressure of the atmosphere, the actual condition of water in the tube and of the film at the top of the column is somewhat changed. Thus Young says in his memoir on the 'Cohesion of fluids,' "when the surface is concave, the tension is employed in counteracting the pressure of the atmosphere, or, where the atmosphere is excluded, the equivalent pressure arising from the weight of the particles suspended from it by means of their cohesion," etc. In fact, it would seem the better plan in explaining the above phenomenon, to make full use of the unquestionable agency of the atmospheric pressure, so long as the atmosphere is present, and be thankful for it, since it is far easier to understand than the sustaining by cohesion that must take its place in a vacuum.

Prof. Leconte's statement of his second principle is a little puzzling; for a natural interpretation of his words would be, that he supposes the surface tension to be inversely proportional to the radius of curvature of the film. He applies his two principles to the explanation of three typical cases of attraction and repulsion. In the case of two moistened bodies he says, "But when brought so near that their meniscuses join each other, the radius of curvature of the united intervening concave meniscus . . . is less than that of the exterior concave meniscuses,

and its superior tension acts upon both bodies toward a common centre of concavity."

We do not think physicists generally will admit that a liquid film tends to draw a solid, to which it is attached toward the centre of concavity of the film. Indeed, if this were so, the tendency of a column of water raised between two floating bodies by surface tension would be to lift those bodies: similarly a column of liquid sustained in a fine tube would tend to lift the tube. This action, however, is denied both by theory and experiment. In fact, unless we have misunderstood Prof. Leconte's language and diagrams, his article will not do all that it was intended to do, toward removing the difficulties in the way of a student beginning the study of capillary phenomena. ·(Amer. journ. sc., Dec., 1882.) E. H. H. 192 Rigidity of the earth.-G. H. Darwin discusses the long-period tides the lunar fortnightly declinational and the lunar monthly elliptic - from 33 years' observations in England, France, and India, and finds that they are reduced to 0.7 of their theoretic height. There should be no reduction on a rigid earth, and no ocean tides on a liquid earth: as the actual effect of the earth's yielding to the moon's attraction is only 0.3 of the difference between these extreme effects, the earth is considered at least as rigid as steel. (Nature, Nov. 2, 1882.) W. M. D.

C. S. H.

Optics.

[93

Molecular refraction. - In an investigation on the refractive powers of carbonic ether and its sulphur substitution products, E. Wiedemann finds that the atomic refraction of sulphur depends upon its place in the molecule as does that of oxygen. (Wied. ann., Dec., 1882.) 194 Dispersion formulas. - A. Wüllner shows that in a large number of colorless substances, in which case the absorption constant may be regarded as zero, two of the constants in Helmholtz' dispersion formula are sensibly equal, and the formula reduces to one of two constants, which is then equivalent to that of Lommel. The same was found to hold true of an alcoholic solution of alizarine, as also of an aqueous solution of amonio-sulphate of copper. (Wied. ann., Dec., 1882.) C. S. H.

195

Diffraction. A series for the calculation of Fresnel's integrals, and a table of values, are given by A. Lindstedt. (Wied. ann., Dec., 1882.) C. S. H. [96

(Photometry.)

Photometric observations of the transit of Venus. Professor E. C. Pickering has made some comparisons of the brilliancy of the sun, of Venus, and of the region in the immediate vicinity of the limb of the sun, whereby the photometric illumination of that portion of the corona may be determined. An ordinary double-image-prism photometer with a few slight modifications, attached to the tail-piece of the 15-inch equatorial, was employed for the observations. Calling the light of the sun 100, the mean of thirty-two settings taken between 1 h. 07 min., and 1 h. 30 min., Cambridge mean time, gave: Venus 1.8, and the sky 8.8. The mean of twenty-four settings taken between 2 h. 48 min. and 2 h. 54 min. gave: Venus 1.4, and the sky 6.2. The mean of all gave: Venus 1.6, and the sky 7.5 or 4.7 times as bright as Venus. [According to this, the light of this portion of the corona would seem to be about 3.7 times as brilliant as the light reflected by that portion of our atmosphere lying between us and the sun.]197

W. H. P.

Heat.

Thermal conductivity of rocks. A novel method has been employed by M. Thoulet for the

determination of the thermal conductivity of minerals and rocks. Instead of measuring the temperatures at different distances from the source of heat, measurements are taken of the time required for the passage of a certain quantity of heat through a section of known thickness. The thermal resistance' is defined as the time required for the passage of a definite quantity from a source at 100° C. through a thickness of 0.01 mm. The thermal resistance is consequently inversely proportional to the thermal conductivity. Glass and iron have already been experimented on, and the method appears to give very accurate results. — (Ann. chim. phys., (5), xxvi. 261.) C. B. P. [98

Heat of combination a function of atomic weight. Mr. Laurie shows, that if the atomic weights of elements are taken as abscissae, and their atomic heats of combination with chlorine, bromine, or iodine, as ordinates of a curve, the heats of combination will be seen to be a periodic function of the atomic weights. — (Phil. mag., Jan., 1883.) C. B. P.

Electricity.

199

Electrical resistance of selenium cells. In a communication to the Physical society of London in June, 1881, Dr. James Moser urged that the decrease in electrical resistance observed in a 'selenium cell' when acted upon by a beam of light, is due to heating, which by expanding the selenium makes it press more firmly against the metallic electrodes of the cell, thus establishing better connection. The fact that luminous are more effective than obscure rays in producing the observed change, Dr. Moser sought to explain as a result of selective absorption. Mr. Shelford Bidwell undertook to put Dr. Moser's theory to the proof by heating selenium cells to known temperatures in the dark, and observing the consequent change in electrical resistance. It appears from his experiments, that below a certain temperature, which is different for each cell. heating increases the electrical resistance of the cell; that above this temperature heating decreases the resistance, the temperature of maximum resistance being usually somewhat above ordinary temperature, but in one case being 13° C. Mr. Bidwell concludes, however, that the action of the luminous rays upon the cell cannot be explained by their heating effect alone; for he finds that whereas a moment's exposure to direct sunlight, though causing a great fall of electrical resistance, yet heats the selenium to a hardly perceptible extent, an equal decrease of resistance caused by heating in the dark could be produced only by making the cell too hot to handle. Mr. Bidwell concludes from his experiments that the action of the carbon photophone is to be explained by the heating alone. - (Phil. mag., Jan., 1883.) E. H. H. [100

ENGINEERING.

Practical test of the safety of bridges. — It is well known among engineers, that, with good iron properly used, our bridges may be relied upon for an indefinite length of service. The best practice never loads a structure with more than from one-fourth to one-sixth of the weight that would break it down. Any load put upon a piece of iron will stretch it to a slight extent. Upon removing the load, the iron should regain its original form. This it will do if it has not been overstrained. A very simple and effective piece of mechanism has been for some time in use at the East-River suspension-bridge at Brooklyn for determining the precise effect of any load upon any part of the structure. A bar ten or twelve feet long is attached to any member of the bridge in such a manner that any increase in the length of such

member is at once imparted to the standard bar, and is so multiplied by delicate mechanism as to become plainly visible. In testing a bridge, a movable index upon the standard bar is first placed at zero. A load is then run on to the bridge, when the index moves on account of the stretch imparted by the bridge to the standard bar. The weight is now removed from the bridge, when the index returns to zero unless the iron has received a permanent elongation from the load that is, unless the iron has been overstrained. Not only does this method enable us to determine whether a bridge is safe for the time being; but we can also answer the not less important question, whether the bridge is holding its vitality through long periods of time. The above apparatus is so delicate as to indicate a strain on the iron less than a thousandth part of the weight that would break it. By means of this device, not only do we substitute exact measurement for mere opinion, but we are enabled to answer a good many vexed questions in regard to the precise condition of complex structures of iron.

G. L. V.

[101

Cable power for street-railways. There is probably no more abused piece of motive power than the horse which draws our street-cars. Leaving out of view the outrageous cruelty to which these unfortunate animals are often subjected, it may well be questioned whether such power is in any way economical. Whether steam or electricity will soon be employed upon street railways, may be questioned; but there is reason to think that the so-called cable system may furnish a solution to many of the problems in city transportation. There is nothing new in the idea of a continually moving, endless wire cable beneath the roadway, to which cars may be attached at any point; but to reduce the idea to practice involves a good deal of mechanical skill and a very considerable expense. Mr. J. D. Miller gives a description of the Chicago cable roads, in which he states, that, in October last, there were in Chicago over four miles of cable roads in operation, an amount which has been largely increased since that time. The first cost of these roads is reckoned to be not less than $100,000 a mile for a double track. The cost of operation is said to be much less than by the common method, the percentage of saving being greater as the traffic becomes larger. (Journ. assoc. eng. soc., Oct.) G. L. V. [102 Tests of building materials. An important series of experiments upon the strength of timber has been for some time past carried on by Professor Gaetano Lanza at the institute of technology in Boston, and also at the Watertown arsenal. The experiments from which the data in our books have been determined were in nearly all cases made upon very small and very carefully selected pieces of wellseasoned wood. From the data thus obtained we have assumed that we could at once pass to the more or less defective and generally quite unseasoned timber which is employed in actual work. This method has often led to most absurd and unreliable results, and has been a fruitful source of that discordance which so often appears between science and practice. Instead of small wooden beams an inch square and two or three feet long, Professor Lanza uses beams twenty feet long and of the common sizes used in building; and, instead of the perfectly clear and well-seasoned material employed by the older experimenters, he takes his beams just as they come from the lumber-yard. In fine, the experiments now being carried on are as far as possible under the real conditions of practice, and not under the imaginary conditions of the closet. The result of these experiments will put into the hands of the engineer far

Thorite and the equivalent of thorium. — In a variety of thorite recently discovered at Arendal in Norway, L. F. Nilson finds a large percentage of iron, lead, and uranium, the latter in the form of dioxide. To separate thorium from cerium oxide, after precipitating the oxalates they were converted into sulphates, and advantage was taken of the slight solubility of hydrous thorium sulphate at 0°. In determining the atomic weight of thorium, the purified sulphate Th (SO4)2. 9 II O was ignited at first gently to expel the crystal water, then to a glowing white heat until the acid was driven off. As a mean of ten determinations calculated from the residue Th O2, the value 235.43 was obtained. The metal was prepared in nearly the theoretical quantity by igniting potassium thorium chloride mixed with a few grms. of salt, and covered with sodium in a tube filled with salt. When heated in a current of chlorine gas, the metal is converted into the chloride. It unites readily with bromine and iodine, and is easily soluble in acids. Under no conditions does it decompose water, nor is it attacked by alkaline hydrates. (Berichte deutsch. chem. gesellsch., xv, 2519.) C. F. M.

C. F. M.

[105

Modification of the law of isomorphism.An examination of the isomorphous metatungstates and tungstoborates, by D. Klein, led to results which could not be explained by the law of Mitscherlich. A better interpretation was found in a modification of the latter part of this law, first proposed by M. de Marignac. "Isomorphous bodies either have a similar chemical composition, or they consist chiefly of the same group of elements or of groups with identical chemical functions." (Comptes rendus, xcv., 781.) [106 - - In the Electrolysis of hydrochloric acid. electrolysis of hydrochloric acid, using platinum electrodes, D. Tommasi finds that the heat absorbed in decomposing two molecules of the acid amounts to 78.6 cal. Since platinum chloride was found in solution, a certain quantity of the electromotive force (not determined) must have been absorbed in its formation. One Daniell's cell (E=49 cal.) with one zinc-cadmium element (E16.6) decomposed the acid, but no chlorine appeared at the positive pole. With two Daniell's cells, bubbles of an oxide of chlorine were observed. When dilute hydrochloric acid (1 conc. acid: 20 HO) was subjected to electrolytic action, the liquid at the positive pole became yellow and exerted a strong bleaching action. M. Tommasi regards this action as due to the formation of hypochlorous acid which attacks the electrode in the concentrated acid solution. (Comptes rendus, xcv., 689). [107

C. F. M.

Changes of volume and of molecular arrangeAn unequal expansion ment in hydrous salts. of the alums when heated led E. Wiedermann to con