ADVERTISEMENT.

The object of the GENERAL APPENDIX is to furnish summaries of scientific discovery in particular directions; occasional reports of the investigations made by collaborators of the institution; memoirs of a general character or on special topics, whether original and prepared expressly for the purpose, or selected from foreign journals and proceedings; and briefly to present (as fully as space will permit) such papers not published in the "Smithsonian Contributions" or in the "Miscellaneous Collections" which may be supposed to be of interest or value to the numerous correspondents of the Institution.

180

RECORD OF SCIENTIFIC PROGRESS.

INTRODUCTION.

While it has been a prominent object of the Board of Regents of the Smithsonian Institution from a very early date in its history to enrich the annual report required of them with scientific memoirs illustrating the more remarkable and important developments in physical and biological discovery as well as the general character of the operations of the Institution, this purpose has not hitherto been carried out on any very systematic plan. Believing, however, that an annual report or summary of the recent advances made in the leading departments of scientific inquiry would supply a want very generally felt, and would be favorably received by all those interested in the diffusion of knowledge, the Secretary has had prepared by competent collaborators a series of abstracts showing concisely the prominent features of recent scientific progress in astronomy, geology, physics, chemistry, mineralogy, botany, zoölogy, and anthropology. Other subjects which might properly have been included, such as those of terrestrial physics and meteorology, geography and hydrography, microscopy, &c., as well as the more practical topics of agricultural and horticultural economy, engineering, technology, and industrial statistics have, for the present, been omitted, both for want of time in which to have them properly digested and for want of space to allow them any sufficient presentation. With every effort to secure prompt attention to all the more important details of such a work, various unexpected delays frequently render it impracticable to obtain all the desired reports in each department within the time prescribed. In such cases it is designed, if possible, to bring up such deficiencies and supply them in subsequent reports.

A similar digest, having the title of "Annual Record of Science and Industry," prepared under the general editorship of the present Secretary of the Institution, was commenced in 1871, and published in a duodecimo form by the Messrs. Harper, of New York.* This work was con

*The "Annual Record of Science and Industry" was itself a successor to a similar year-book entitled "The Annual of Scientific Discovery" commenced in the year 1850 under the editorship of Mr. David A. Wells, and published by Messrs. Gould and Lincoln, of Boston. The last-mentioned work was satisfactorily continued for sixteen years, from 1850 to 1865, inclusive, when it was suspended by the appointment of its editor, Mr. Wells, to the commissionership of internal revenue under the United States Treasury Department. The work was, however, resumed in 1867, under the editorship of

tinued through eight annual volumes; but was discontinued with the volume for 1878. The present undertaking may, therefore, be considered as in some sense a continuation of the work published by the Messrs. Harper.

It is scarcely necessary to remark that in a résumé of the annual progress of scientific discovery so condensed as the present, the wants of the specialist in any branch can be but imperfectly supplied; and very many items and details of great value to him must be entirely omitted. While the student in a special field of knowledge may occasionally receive hints that will be found of interest, he will naturally be led to consult for fuller information the original journals and special periodicals from which these brief notices or abstracts have been compiled.

The contemplated plan of devoting some 250 pages of the annual report to such a compilation is not designed to preclude the introduction into the "General Appendix," as heretofore, of special monographs or discussions that may prove interesting to the scientific student.

SPENCER F. BAIRD.

Dr. Samuel Kneeland, who conducted it for the years 1867, 1868, and 1869. It then passed under the editorship of Prof. John Trowbridge, for the years 1870 and 1871, when it was finally discontinued, and the "Annual Record of Science and Industry" took its place.

ASTRONOMY,

BY PROF. EDWARD S. HOLDEN.

INTRODUCTION.

As the space available for the record of astronomical progress is comparatively small, the accounts here given must necessarily be the barest summaries, whose chief end is to call attention to work which has been done, in order that a reference may be made to more extended papers if desired. At the same time it is clearly impossible to give a specific reference to each of the papers consulted.

For such bibliographic information the reader is once for all referred to DARBOUX et HOUEL'S Bulletin des Sciences Mathématiques et Astronomiques (monthly, Paris), to Nature (weekly, London), to Science (weekly, New York), to the Observatory (monthly, London), and to other standard journals. Free use has been made of reviews by writers in these and other periodicals, particularly of the Record of Astronomy, published by Dr. J. L. E. DREYER in the Scientific Proceedings of the Royal Dublin Society.

NEBULÆ AND CLUSTERS.

The Earl of ROSSE has published Parts 1 and 2 (0 to 14 R.A.) of the "Observations of Nebula and Clusters of Stars made with the sixfoot and three-foot reflectors at Birr Castle from the year 1848 up to about the year 1878" (Trans. R. Dublin Soc., Vol. II). This publication (of which the third part, comprising the last ten hours of R.A., is in the press) embodies all the work done on nebulæ since the erection of the six-foot telescope in 1845. In 1850 and 1861 abstracts of the observations on more interesting objects appeared in the Philosophical Transactions, but all these abstracts are given over again in the new publication, with the sole exception of the copperplate engravings, to which, however, in all cases references are made in the text. Though even now not every single note in the observing ledgers is published, nothing has been suppressed which can be of the slightest value or importance. The observations are given in the observer's own words, and the notes which were added by Mr. DREYER while arranging the work for publication are easily distinguished by being inclosed in brackets. These notes deal especially with questions of identification, and nearly all the new nebula which were found at Birr Castle in the course of years and which

formed the weak point of HERSCHEL'S General Catalogue, have now by re-examination and comparison with D'ARREST's observations been identified and their positions determined. The work done during the last five or six years (1872-'78) differs in many particulars from the observations taken in earlier years, with which the paper of 1861 made the scientific world acquainted. Most of the more important nebulæ having been frequently drawn, there was latterly not much to be done in this direction, but another important field was opened up by taking micrometric measures of groups of nebulæ, or of nebulæ and neighboring stars. Into the text have been introduced diagrams of such groups or of a nebula and the stars near it, while four plates contain lithographic reproductions of more elaborate sketches, which had not already been published among the engravings in the former papers. How much more detail is given in the new publication than in the paper of 1861 may be seen from the circumstance that while the fourteen hours of R.A. in the latter only cover 34 pages, in the new paper they extend over 129 pages.

A series of measurements of all the planetary nebulæ has been commenced with the 15-inch refractor of the Harvard College Observatory. Dr. C. H. F. PETERS has lately published in Urania an important list of nebulæ found on his ecliptic charts.

Photographs of the Nebula of Orion.-Prof. HENRY DRAPER distributed in 1880 a large number of photographs of the nebula in Orion, taken by means of his 11-inch Clark refractor with an exposure of 51 minutes. Stars down to the 10th magnitude were shown and the details of the more prominent masses of the central and brightest regions were for the first time permanently and automatically registered. The work so well begun has been brilliantly prosecuted, and in March, 1881, Dr. DRAPER succeeded in obtaining fine photographs with an exposure of 140 minutes! These give a much greater extent to the nebulous portions registered and bring out many details, and what is astonishing they show stars whose magnitudes Prof. PICKERING has photometrically determined to be from 14.0 to 14.7 of Pogson's scale. The minimum visibile of an 11-inch telescope is about 14.2, so that it really ap pears that Dr. DRAPER has photographed stars which are very near the limit of naked eye vision if not actually below it. The mechanical perfection of the appliances which render such feats possible can only be appreciated by those used to the apparatus furnished by the best makers, which is far inferior to that made by Dr. DRAPER for his own

use.

FIXED STARS.

Fixed stars, catalogues of stars, star charts, double stars, binary stars, variable stars, etc.-Decidedly the most important recent contribution of observing astronomy is the "Uranometria Argentina*" of Dr. GOULD.

*"Resultados del Observatorio Nacional Argentina." Vol. I, "Uranometria Argentina," Buenos Aires, 1879, 4to, with atlas.