dency has been, perhaps, too much the other way. Ten thousand years seems a short time for the completion of such great changes as we find in river-beds, in lake-margins, and in mammalian species.

In the last chapter the author discusses the relation of the Bible to science. Perhaps the time is not yet fully ripe for final adjustment here. But one thing is meanwhile certain : all the harm which has come, or will ever come, of the discussion of this subject, comes only of a narrow, intolerant spirit on both sides. Nothing but good can come of the freest inquiry, if only it is conducted in a simple, reverent, truth-loving spirit.

6

But as many will think that a reviewer is 'nothing unless critical,' we must find some faults, even if they be but errors of typography, or slips of the pen. Of the former, we find one on p. 329, where 70° instead of 20° from pole is given as the position of the antarctic continental ice-foot. Among the latter, we notice on p. 310 that the bluff-deposit of the Mississippi River is spoken of as the orange sand.' The bluff-deposit is a very fine silt (loess) overlying the coarse orange sand. Again: the transition from paleozoic to mesozoic can hardly be called one from waterbreathing to air-breathing animals,' since airbreathing insects lived in the Devonian, and air-breathing insects and amphibians were abundant in the carboniferous.

Finally, we should state that the book is illustrated by several plates, which greatly increase its value.

next best plan is at least to carry on topographic surveys wherever possible, and secure, as soon as may be, the good results of a close knowledge of the form of the various states. Such work is going on in New York, and a careful triangulation has been carried across the state; but, with the appropriation at present grudgingly afforded this work, many years must pass before it is completed. New Hampshire has taken advantage of a triangulation executed for it by the U. S. coastsurvey, and constructed a large six-sheet map on a scale of two and one-half miles to the inch (1158,400), with contour lines every hundred, and in parts every fifty, feet; but these latter are by no means of final accuracy. This map was issued with geological coloring in 1878; and that part including the White Mountains has been published apart in Appalachia, vol. i., uncolored, and also by the surveyor, Mr. H. F. Walling, with hypsometric coloring. Another notable contour-line map is that of 'Morrison's Cove,' surveyed by Mr. R. H. Sanders, to illustrate Mr. Fr. Platt's report on Blair and Huntingdon Counties, Penn. (Second geol. surv. Penn., T., 1881). It is printed in fourteen large sheets, on a scale of sixteen hundred feet to an inch (1:19,200), or about three and one-half inches to a mile, with contours every twenty feet, and is colored geologically. Being in a region of typical Appalachian form, it has an especial value in showing this remarkably interesting style of mountain surface. mountain surface. A photographic plate from a model constructed from this map by Mr. E. H. Harden has been published (Proc. Amer.

JERSEY.

A topographical map of a part of northern New Jersey, from surveys and levellings made, and local surveys corrected. By GEORGE W. HOWELL, C.E., and C. C. VERMEULE, C.E. Julius Bien, lith., 1882. 87.5 x 88 cm.

ALL of our state geological surveys have been hampered by a lack of topographic maps on which to record and publish their results. The geological maps thus far completed have in nearly all cases been based on compilations of county and other surveys, executed at different times, on different plans, and seldom with sufficient geodetic triangulation to insure accuracy. Representation of mountain form is in nearly all cases excessively incorrect. When careful topographic surveys have been made, they have unfortunately too often followed instead of preceded the geological examination. As it is now too late to go back and perform the work in proper order, the

the intricacies of Pennsylvanian topography than any thing else that has yet appeared. It is to be hoped that the other models constructed for the Pennsylvania survey may be treated in the same way. A second example of fine topographic work on the same large scale is in the lately issued map of the Panther Creek basin by Mr. R. P. Rothwell (see SCIENCE, p. 310), which makes the first of a series of maps that will illustrate the survey of the anthracite district of Pennsylvania, in charge of Mr. Ashburner. The large number of accurate surveys of private property in this region, and the numerous railroads crossing it, will furnish a valuable basis for the final work of the state geologists, and its interesting form and unique structure will at last find adequate representation.

The topographic map now in course of construction and publication by the Geological survey of New Jersey, under the direction

of Prof. G. H. Cook, bids fair to outrank those already mentioned, as it alone combines all the elements for successful completion. It has the advantage of thorough triangulation, including twenty-six primary stations furnished by the U. S. coast-survey, a work still in progress, but approaching an end. This is illustrated by a very delicately prepared map in Professor Cook's annual report for 1882. The process of local triangulation and levelling was begun in the northern part of the state, and field-observation is already done for most of the area lying north of a line from Belvidere to Sandy Hook. The area of which the sheets have been published contains 847 miles of New-Jersey land, and laps eastward on New York. Its centre is near Orange, and it includes Paterson and Perth Amboy north and south, and Brooklyn and Boonton east and west. The scale is one mile to an inch (1: 63,360), sufficiently detailed to show all the artificial topography even in the city portions of the map, and to include many of those mythical rectangular streets laid out on town plans, and accepted' by the local authorities, although often entirely regardless of the lay of the land. The contours are drawn in faint red lines, showing differences of level of ten feet in plain country, and twenty feet in the hilly portions. Water-surfaces are colored blue, and depthlines are drawn at intervals of ten feet. The chief topographic features thus shown are the strong, regular lines of the triassic trap-ridges, -the Palisades and the double Wachung Mountains, with their bold eastern face and long slope, on the west; the more irregular highland country of the azoic rocks, on the north-west; the great area of salt-marsh lands, built up to tide level along the Hackensack River and Newark Bay; the extensive fresh marshes and flats on the upper course of the Passaic, within the curve of the Wachung range,

the remains of an old lake held by drift-barriers, as explained in the report for 1880; and, finally, the line of the terminal moraine, especially as it crosses the flat sandstone country from Metuchen northward to Locust Grove, where it climbs the trap-range. Even in this short distance, over forty of its characteristic little ponds, that would be quite unnoted on ordinary maps, are shown upon its rolling back. The completion of this map for the entire state will be an immense gain for its people.

The distinctly practical ends that mark the work of the New-Jersey survey justify the subordination of natural to artificial topography; the former being mostly indicated in the fainter

red, and the latter in the stronger black lines. It would be, however, of much practical as well as scientific interest to try a reversal of these colors on a special edition of the map, in order to show more distinctly the natural features of the state, and give a properly secondary place to the towns, railroads, and lettering. As now printed, the ridges of the Wachung Mountains are rivalled by the Central railroad with the parallel roads beside it; and the mountain form is obscured, except to a very close search, among the streets of Orange and Paterson. And, as where so much good work has been accomplished we naturally look for more, it seems not too much to hope that future years may see the entire map appear with geological colors, in which the detrital surface-deposits are shown, as well as the consolidated underlying formations, the latter being indicated only where they outcrop, or are covered by an insignificant soil.

CRUSTACEA OF THE BLAKE AND TRAVAILLEUR EXPEDITIONS. Recueil de figures de crustacés nouveaux ou peu connus. Par M. A. MILNE-EDWARDS. lère livraison. [Paris], April, 1883. 3 p +44 pl. 4°.

The

THE Coast-survey dredgings, under the direction of Pourtalès, in the Straits of Florida, first revealed the wonderful richness of the crustacean fauna beyond the shallow waters of our southern coast. The earlier collections of Pourtalès were unfortunately lost in the great Chicago fire; but Stimpson's preliminary report on the Brachyura, published in 1870, gives some indication of their extent. subsequent explorations, under the direction of Pourtalès, the elder Agassiz, and Stimpson, more than replaced the collections destroyed at Chicago; while the work of the Blake, under the direction of Alexander Agassiz, in 1877, 1878, 1879, has far excelled all earlier explorations in bringing to light great numbers of new and remarkable forms. All the crustacea from these later explorations have been submitted to Alphonse Milne-Edwards of Paris, who has from time to time described and figured a considerable number of the Brachyura in his great work on the crustacea of Central America and the Mexican region. The prog

ress of this work has been exceedingly slow, however, the Carcinoplacidae not yet being reached; so that the groups containing the most remarkable forms were left untouched until the appearance of the preliminary report on the Blake crustacea in the bulletin of the Museum of comparative zoology. This short report, though extending only to the higher Macrura,

enumerates over two hundred species, and characterizes as new to science twenty-eight of the genera and more than a hundred of the species. As a continuation of this report, preliminary notices of more of the Macrura appeared in the Annales des sciences naturelles for 1881. The explorations of the Travailleur on the other side of the Atlantic in 1880, 1881, 1882, have also brought to light numerous new forms, which have been briefly described or mentioned by Milne-Edwards in several reports upon the work of the Travailleur. These preliminary reports of MilneEdwards, though they revealed astonishing discoveries, gave very little idea of the strange new forms discovered; and the accumulation of such a mass of imperfectly described genera and species was fast becoming a serious obstruction to the work of others in the same department. The work which is the subject of this notice begins to obviate this difficulty by the issuing of advance figures of the new forms referred to.

This first fasciculus of the work consists of a titlepage and a two-page list of plates printed by some autographic process, and forty-four plates, of which thirteen are engraved, and the rest printed like the titlepage and list of plates. The engraved plates are all proofs before letter, and represent species from the Travailleur expedition only, while the autographic plates represent species from both Travailleur and Blake expeditions, and a few from other sources. None of the plates are numbered in any way, - an unfortunate omission, which renders references to them difficult; but the names of the species are printed on them, and on the autographic plates the station and depth are usually added. The whole number of species figured is sixty-one; of which thirty-one are from the Travailleur, twenty-six from the Blake, three from the U. S. fish-commission, and one from the Godeffroy museum. The autographic plates, though rough in appearance, are apparently quite as accurate as the highly finished engravings, and have the great advantage of showing the work of the draughtsman only.

The most remarkable forms figured are from the Blake collection. Phoberus caecus, one of these, a Macruran as large as the lobster, resembles Palaemon in external form, but has rudimentary eyes not projecting beyond the carapax, and is said to have branchiae like the Astacidae. Xylopagurus rectus is a hermitcrab, which inhabits tubular stems of plants open at both ends, has a bilaterally symmetrical abdomen with the penultimate somite developed into a calcarous operculum, which closes

the posterior opening of the tube. Pylocheles Agassizii, another hermit-crab, lives in cavities in hard fragments of agglutinated sand, and has a well-developed, symmetrical abdomen like the typical Macrura. One of the most interesting types is Glyphocrangon, represented by three species, the figures of which well illustrate the utility of figures and the slight value of Milne-Edwards's preliminary descriptions. The figures show Glyphocrangon to be the same as my Rhachocaris, figured and described in a report on the Blake crustacea of 1880 (Bull. mus. comp. zool., x.). The genus was described by Milne-Edwards as having the telson completely consolidated with the preceding somite; which is not the case, the telson having a movable, though peculiarly constructed articulation, which is like the articulations between the three preceding somites of the abdomen. The structure of these articulations, which seem to have been wholly overlooked by Milne-Edwards, is so remarkable that I quote the following from my original description:

"In addition to the ordinary hinge at each of the articulations, there is a process arising from the anterior somite just below the hinge, and curved backward and upward concentrically with the hinge; and this process fits accurately, and is slightly overlapped along its edges by a similarly curved groove in the posterior somite. When the abdomen is completely flexed, the ends of these curved processes project dorsally considerably beyond the grooves; but, when the abdomen is fully extended, the processes are withdrawn so as to expose the dorsal part of the groove; and in this position, in the contracted alcoholic specimens, the somites are firmly clamped, apparently by the pressure of the ends of the processes upon the concave posterior walls of the grooves, and held rigidly extended, so that it is very difficult to flex the somites, unless the tip of the abdomen is pulled backward with considerable force, when the processes slide easily through the grooves, and the somites are readily flexed. It is probable that in life, while the extensor muscles of the abdomen are relaxed, the processes move easily through the grooves; but, when the extensor muscles are strongly contracted, the hinges are clamped, as in the alcoholic specimens, so that the animal can voluntarily hold the telson and the spiny terminal somites of the abdomen rigidly extended as a means of self-defence."

Another remarkable peculiarity of the genus, not noticed by Milne-Edwards, is the articulation of the coxae of the external maxillipeds with the edges of the carapax. Pontophilus Jacqueti, from the Travailleur expedition, is evidently not a Pontophilus, but a Ceraphilus, and is apparently identical with my C. Agassizii from this side of the Atlantic.

Nearly half of the species figured apparently belong in or near Pandalinae and Ephyrinae, which seem to be the most abundant of the deep-water Macrura. S. I. SMITH.

ASTRONOMY.

Siemens on solar physics. In a recent lecture at the Royal institution, Sir. W. Siemens discusses the subject of solar radiation. He gives reasons for fixing the temperature of the photosphere at about 2800° C., based, first, upon the behavior of a rod of carbon and a gas-flame in the focus of a reflector exposed to the sun; second, upon a comparison between spectra of different luminous intensities; and, third, upon experiments for determining the relation between temperature and radiation made by means of an iridio-platinum wire a metre long, heated by an electric current. He finds the radiation to be expressible by the formula, Radiation Mt2 + pt, M being a coefficient due to the radiating substance. He discusses also the effect of diminished pressure in lowering the dissociation temperature of compound gases, and restates and advocates anew his last year's theory of the maintenance of the solar heat. - (Nature, May 3.) C. A. Y. [1061 Scintillation of stars as affected by the aurora borealis.-M. Ch. Montigny, observing for many years at Brussels, has noticed, as previous observers have done, that the scintillation of stars is much increased during the occurrence of an aurora. He has noticed, further, that every aurora' produces immediately its effects upon the scintillation,' that stars in the north are most affected, and that the influence of the phenomenon is most marked for the stars which are observed across the upper regions of the air. Magnetic disturbances also, even when accompanied by no aurora visible at Brussels, increase the scintillation to a marked extent. On two occasions during July, 1881, the effect of magnetic disturbances was observed with no aurora visible in Brussels, or even, so far as can be learned, in any part of Denmark. (Comptes rendus, Feb. 26.) E. H. H. [1062 Deviation of axis of meridian-circle.-M. Loewy of the Paris observatory gives two new methods of determining the azimuth constant of a meridian-circle. The first method depends on the following principle: if we take two points in the path of a star so that the chord joining them is approximately at right angles to the instrumental plane, and not greatly different in length from the polar distance, the inclination of the instrumental axis to the equator can be determined by readings of the instrumental declination and distances from the instrumental plane. Owing to the limited field, only those stars whose polar distances are about 1° 40′ or less can be used.

About one hour and forty-six minutes before meridian-transit, simultaneous readings of the right ascension and declination micrometers are made, and also a reading of the circle. It is not necessary to record the time. After an interval of about three hours and a half, the series is repeated. The chord of the path described by the star during this interval will equal its polar distance. From these observations, we can deduce the inclination of the instrumental axis to the equator, and by means of this the azimuth constant, without using the right ascension of the star. The method gives thus an independent determination of the azimuth. The old method, that of upper and lower culminations of the same star, requires an interval of twelve hours, thus greatly increasing the uncertainty of the determination on account of instrumental changes; besides, for a large part of the year it can be applied to only one star, a Ursae Minoris.

M. Loewy's second method, which he does not

consider as good as the first, depends on observations of the distance of the star from the instrumental plane, time of observation being accurately noted. When both right ascension and inclination of axis are sought, it is best to observe these polars at an hour angle of about three hours. When the interval between observations is twelve hours, the inclination of the axis can be determined independent of the right ascension.

M. Loewy gives some results of determinations of inclination by his first method which show a very close agreement with the results given by that ordinarily employed. He believes that the probable error of his method will not exceed 0.02.-(Comptes rendus, April 16 and 23.) M. Mc N. [1063

MATHEMATICS.

Spherical representation of surfaces. In a series of previous communications, M. Darboux treated the particular case of spherical representation when the spherical images of the lines of curvature form an orthogonal and isothermal system. In the present communication, he shows how the method previously employed conducts to the complete solution of the problem of spherical representation whenever this solution can be obtained in finite terms. Employing certain propositions due to M. Montard, the author arrives at the conclusion that we can obtain all the cases in which the problem of spherical representation is susceptible of a solution in finite terms, and that, whenever the problem of spherical representation has been solved in any manner for a system of orthogonal curves, we can derive from the obtained solution an entire unlimited series of orthogonal spherical systems. (Comptes rendus, Feb. 5.) T. c. [1064

Motion of a material point. - In concluding a paper on a certain peculiar case of the motion of a material point, M. Gascheau considers the problem of finding the equations of motion of a material point acted upon by a central attractive force, varying inversely as the cube of the distance from the point to the centre of action. The trajectory is shown to be an hyperbolic spiral. The curve itself is discussed, and a formula is obtained for its rectification. Special phases of the motion of the point are also investigated. (Bull. soc. math., x. no. 7.) [1065

T. C.

Partial differential equations. It is impossible to do more than call attention to this memoir by M. Lemonnier, which treats of the integration of partial differential equations of the first order in n independent variables. The process followed is new, and decidedly simple and interesting; but an abstract can scarcely be given here without introducing a good deal of algebraical work. (Bull. soc. math., x. no. 7.) T. C. [1066

A differential equation. - Capt. MacMahon considers the differential equation,

Xdx + Ydy + Z3dz = 0, where X and Y are cubic functions of x and y respectively. The equation obtained from the above by dropping out the term in z has been investigated by Allegret (Comptes rendus, lxvi. p. 1144), who has obtained the integral in an irrational form. If a denote the constant of integration, Allegret's result is symmetrical in x, y, and a. Capt. MacMahon puts a equal to z, and obtains a solution of the above equation in the form of a rational algebraical integral.

Prof. Cayley adds an interesting note to this paper. — (Quart. journ. math., Feb.) T. C. [1067

PHYSICS. Optios.

Reversal of hydrogen-lines. Liveing and Dewar communicate to the Royal society an interesting note, showing, that, when the induction-spark is taken between electrodes of aluminium at a pressure of two or three atmospheres, the reversal of F is easily obtained; that of C, only with difficulty. By spirting fine drops of water with a pipette into the electric arc, the hydrogen-lines become brilliantly, and, so to speak, explosively' visible for an instant, but without any reversal.(Nature, May 3.) C. A. Y. [1068

(Photography.)

Iodide of silver in the emulsion. - Herr Schumann has been experimenting on emulsions sensitized by combinations of the iodide and bromide of silver. Capt. Abney, Dr. Eder, and Dr. Vogel found that the introduction of iodide diminished rather than increased the sensitiveness of the emulsion, while Herr Schumann obtained the opposite result. He now finds the cause of this discrepancy to be, that while the former authorities prepared their iodide and bromide emulsions separately, and then mixed them, in order to obtain accurate quantitative results, he has been in the habit of precipitating the two together in one and the same solution, as would be done in the practical working of the process. As prepared by the former method, the emulsion is of a pale yellow color; while, by the latter, it is darker and of a citron-yellow tint. The sensitiveness of the mixed emulsions is at a maximum in that portion of the spectrum lying between F and G. It has a lower maximum in the vicinity of the line, and is practically insensitive to the region half way between G and h. The spectrum of the combined emulsion differs from the above in having a distinct maximum between b and F, and in its much greater sensitiveness to the less refrangible rays. (Brit. journ. phot., April 27.) W. H. P. [1069

Photographing the vocal organs. - Messrs. H. T. Wood, Behnke, and Cadett have recently succeeded in photographing the vocal organs in action. An electric light and laryngoscope were employed. It was necessary, in these experiments, to so arrange the light, that the singer should at the same time be enabled to see that the mirror was in the proper position, and also that the image was reflected directly into the camera lens. The light was placed by the side of the camera, and a little in front of it; and the rays were directed by means of a condenser upon a mirror placed immediately above the lens ; this mirror being set at an angle of 45° so as to direct the light upon the subject. The condenser was furnished on the side next the lamp with a waterjacket, through which a current of water was kept flowing to prevent injury to the lens from the heat of the lamp. The rays from the first mirror were received upon the small laryngoscopic mirror placed at the back of the throat, and the image formed in this was reflected upon another small mirror fixed to the front of a drop-shutter; the object of this arrangement being to enable the person whose organs were being photographed to see when the image was properly directed. When this was done, he gave the signal to the operator, and the exposure was made. In some of the latter experiments, arrangements were adopted by which a pair of stereoscopic lenses

Other experiments showed, that, when a given current was trebled, the difference of potential between the poles was slightly increased. The authors have also tested the relation between length of the arc and the difference of potential between the poles. A large number of experiments were made for this purpose with a Brush machine, giving currents varying between 5.5 and 10.4 ampères, the distance between the carbon points varying between 0 and 1 inches, and the difference of potentials from 0 to 140 volts, the carbons being 0.24 inch thick. The results are plotted, giving a curve for which the approximate equation is,

E63 + 55a63 × 10-10a, where E is the difference of potentials in volts, and a the distance between the points in inches. mag., May.) E. H. H.

ENGINEERING.

(Phil. [1071

The steamer City of Fall River. The steamer City of Fall River, which has been recently added to the Fall River line between New York and Boston, exhibits some decided innovations. The engine, of 2,000-horse power, was designed and built by Messrs. A. & W. Fletcher of New-York City. It is a compound beam engine, fitted with the Morgan feathering paddle-wheels, and supplied with steam by a Redfield boiler, all of which features are unusual. The steam-cylinders are 44 inches diameter by 8 feet stroke, and 68 inches by 12 feet stroke. The wheels are 25 feet 6 inches in diameter. The boilers are of Otis steel, and are tested to 150 pounds pressure per square inch. The boat is 260 feet long, 41 feet beam, 17 feet deep. Over the guards the breadth is 73 feet. The draught of water, loaded with 600 tons of freight, is 12 feet. This steamer has made the 181 miles from port to port in 10 hours, and has made 17 miles an hour! The coal consumption is small,-20 tons per round trip. (Sc. Amer., May 5.) R. H. T. [1072

CHEMISTRY. (Organic.)

Oxidation of 'aromatic monamines and diamines. When equal molecules of dimethylparaphenylendiamine aud dimethylaniline in an aqueous solution with zinc chloride were treated with the