stone.

the westward. They contain not less than 80 separate beds of limeNo additional evidence appears to have been obtained in regard to the age of the gypsum-bearing strata immediately above the Permian, and none relating to the more recent formations.

The report contains a chapter on economical geology, which, with the separate Reports appended, furnishes much information of value to all interested in Kansas.

2. First Annual Report of the Geological Survey of Iowa; by C. A. WHITE, M.D., State Geologist. 4 pp., 8vo. Des Moines, 1867.-This Report is merely a preliminary notice of the organization and commencement of the present survey during the past year. A brief Report by the State Chemist, Prof. Hinrichs, is appended.

3. Report of the Progress of the Geological Survey of North Carolina, 1866; by Prof. W. C. KERR, State Geologist. 56 pp., 8vo. Raleigh, 1867.-A brief Report, containing some information on the geology of the State, but mainly interesting as showing that its geological exploration is begun again in good earnest.

4. Geological Survey of Canada, Sir Wм. E. LOGAN, Director. Report of Progress from 1863 to 1866. 322 pp., large 8vo. Ottawa, 1866. This Report reached us too late for a notice in this place.

5. On the Rock Salt Deposit of Petit Anse, Louisiana Rock-Salt Company. Report of the American Bureau of Mines. 36 pp., 4to, with maps. This important report is based mainly on the investigations of Dr. C. A. Goessmann. Dr. Goessmann obtained for the composition of the salt of Petit Anse, chlorid of sodium 98-8823, sulphate of lime 0.7825, chlorid of magnesium 0.0030, chl. of calcium 0.0036, moisture 0.3286 100.

6. Plane Problems in Elementary Geometry: or Problems on the Elementary Conic Sections, the Point, Straight line, and Circle; by S. EDWARD WARREN, C.E., Prof. of Descriptive Geometry, etc., in the Rensselaer Polytechnic Institute. 162 pp., 12mo, with a plate and numerous figures. New York, 1867 (John Wiley & Son).-This little volume is prepared by one who is master of his subject both theoretically and practically, and is an excellent manual for the student or artizan. It gives directions with regard to the use of drawing instruments, is clear and precise in its definitions and demonstrations, and very varied in its problems. 7. The American Naturalist, a Popular illustrated Magazine of Natural History. Vol. I, March, 1867, No. 1. 56 pp., 8vo. Salem, Essex Institute. This first number of the monthly American Naturalist, announced in this volume, at page 136, sustains fully all that was promised. Among its illustrations are two plates, one, of the crater of Kilauea in 1864-5, and the other, of the structure of the Land Snails, with reference especially to those of New England.

8. Description of Fossil Plants from the Chinese Coal-bearing rocks; by J. S. NEWBERRY, M.D., being Appendix No. 1 of Geological Researches in China, Mongolia and Japan, by Raphael Pumpelly. 5 pp., 8vo, with a plate. Smithsonian Contrib. to Knowledge, 1867.-The species are those referred to by Dr. Newberry in his paper in this Journal, vol. xlii, p. 151. 9. Musée Teyler: Catalogue systématique de la Collection Paléontologique, par T. C. WINKLER. Quatrième Livraison. Harlem, 1865.This is a continuation of the Catalogue noticed in vol. xli, at page 287.

THE

AMERICAN

JOURNAL OF SCIENCE AND ARTS.

[SECOND SERIES.]

ART. XXXI.-On certain recent contributions to Astro-Meleorology; by H. A. NEWTON.

1. Radiant points, or radiant areas.

FOR more than twenty years a Committee of the British Association for the Advancement of Science has annually made an extended report on Observations of Luminous Meteors, in which have been given in detail the times, paths, physical appearances, and other phenomena, of meteors seen during the years immediately preceding. No special effort has been made until recently, to elaborate this mass of material. R. P. Greg, Esq., of Manchester, assisted by Mr. A. S. Herschel, at last undertook the task of plotting the paths contained in the voluminous records. By this means they have determined between fifty and sixty radiants, for different periods of the year. Prof. E. Heis of Münster, has in like manner, from observations made by himself and his assistants during a period of twelve years, deduced a similar and, to a considerable extent a corresponding series of radiant points. The latter series is in the Monthly Notices of the Roy. Astro. Soc., xxiv, 213. Both series are in the Report of the British Association for 1864, and in the Proceedings of the British Meteorological Society for Jan. 18th, 1865. From the latter source we give the following table. The general results of Mr. Greg's investigations as regards meteor showers are thus summed up in the Report of the Committee on Luminous Meteors.

"They appear to endure for almost any period, from twenty-four hours to eight or possibly ten weeks, differing from one another in richAM. JOUR. SCI.-SECOND SERIES, VOL. XLIII, No. 129.-MAY, 1867.

Comparison of the epochs and positions of radiant-points of shooting stars, concluded independently by R. P. Greg, Esq., and Dr. E. Heis.

Reference No.

From observations contained in the Brit Assoc. Catalogues, &c., 1845-63. (R. P. Greg.)

Position of
radiant.

1 North

Distinc-
tive

Declina- letters.
tion

Total meteors, 1746; days, 1655; meteor-showers, 56.

(*) Radiants marked thus are extracted from the work by Dr. Heis, entitled 'Die Periodische Sternschnuppen.' (4to. Cöln, 1849.)

ness or intensity of display. In some there appears to be a tendency to maximum display on particular days, as for example xlvii, lasting from November 26th, to December 30th; but the most abundant display occurs from December 9th to 13th. In others no such maximum can be perceived. Their number, of fully fifty as yet ascertained, will probably not be much exceeded, unless by short-lived showers, and by others whose radiants culminate just before dawn. There is no confusion or

chance in their return, but, on the contrary, the showers are very regularly recurrent every year, and, allowing a radiant-region of 10° to 15° in diameter for each, the so-called "sporadic " meteors will become extremely scarce, now that the principal showers and their radiants have been pointed out. A well-marked instance of long persistence and remarkable for having its radiant very small and fixed, is the shower of August 6th to September 10th, No. xxix. The great majority have, at the present time, been as clearly defined (as regards the time of their occurrence, duration, and positions of their radiants) as in the case with the older and better known showers of August and November. On the average of many years, the radiant-regions of a few are, however, still very extensive. In all, a plane, oval, or double-headed region of radiation appears to represent the conditions of the showers more correctly than a point. This elongation of the radiant-region is in most cases perpendicular to the ecliptic, or parallel to the via lactea, in or near which the greater number of the radiants in the latter half of the year are placed. The meteors of particular showers vary in their distinctive characters, some being larger and brighter than others, some whiter, some more ruddy than others; some swifter, and drawing after them more persistent trains than those of other showers. Their connection with the epochs and directions of large meteors still remains to be established."

From a private letter by Mr. Greg to Mr. B. V. Marsh we learn that some minor changes are found neccessary, by further observation and investigation, in the duration of the showers and the places of the radiants. Mr. Greg's charts containing the paths of nearly 2000 shooting stars are about to be published by the British Association. We may hope to receive them within a few months. We evidently need these charts in order to discuss intelligently this important subject. While waiting for them, however, one or two remarks may not be out of place.

That the so-called sporadic shooting stars should belong largely to rings or streams, as do the August and November meteors, is in the present state of our knowledge probable, or at the least is not improbable. The reasonings of Mr. Schiaparelli, which will be spoken of further on in this article, strengthens this probability.

But we meet with some difficulty in accepting the proposition that a ring or stream may be of such breadth as to require eight or ten weeks for the earth to traverse it, that is, that the ring may extend 60° or 70° along the ecliptic; or rather, if there were so broad a ring or stream, it would not appear to have a radiant area so small, and so well marked, as to be detected.

The position of the radiant indicates that point of the heavens from which the relative motion of the meteoroids with reference to the earth is directed. This direction is the resultant of two absolute motions, that of the meteoroids and that of the earth. If either of these should change, the place of the radiant will change.