Annual Record of Science and Industry

Summaries of Progress would be sufficient alone, without any paragraphs recording individual discoveries. It would, of course, be impossible to satisfy such discrepant opinions, and in this dilemma the only resource left to the editor has been to follow a mean which he hopes will be regarded by most as a tolerably happy one. It must be remembered that far more than ten times the space contained in the present volume would be necessary to give even an approximately complete abstract of the progress of science in each of the departments embraced within the scope of this work: much more than that amount will in fact be employed in the annual reports that are hereafter to be made and published on the progress of the several departments of science for the past year. These reports, for 1875, however-unlike the present volumewill not appear till at least one, and, in some cases, two or three or even four years have elapsed. These too are, to a certain extent, addressed rather to experts and special students in the various branches of science than to the general reader, for whom the "Annual Record" is more especially designed. In them the several branches embraced herein are respectively reported upon, in volumes varying from little less than five hundred pages to nearly two thousand each year. Each special department of science has now its own organ for the record of discoveries within its domain. All these are extremely useful to the investigator, and enable him to economize precious time, that would otherwise be spent in frequent reference to numerous volumes, some of which are almost or quite inaccessible to all save a favored few. Several, also, are very elaborate, and the special subdivisions within a single branch are reported upon by experts in the respective subdivisions. Excellent examples of such reports are found in the Jahresberichte and Jahrbücher, published in Germany, on the mathematical, physical, and chemical sciences. Some branches have even two or more annual works devoted to the record of progress in their several spheres; such are especially Zoology, on which one report is published in Germany and another in England; Botany,

which has one in Holland and another in Germany; while for Anatomy there are two in Germany alone. To reports like these (for the most part enumerated in the volume for 1874) must the student refer who desires to obtain information respecting the more technical or special facts or generalizations that have been announced. The present volume can administer to their needs only to a limited extent. But the editor hopes that by the relations which he has established with a number of the inost eminent cultivators of the different departments of science in this country, and through their co-operation, he has been enabled to present as complete and reliable a résumé of discovery as can reasonably be expected within the limited space to which an annual like the present must be restricted.

As now presented, the Record has two distinct parts: (1) the historical summaries of progress during the past year, and (2) the paragraphs communicating in brief the results of investigations by special scientists, or respecting certain subjects. The advantages of the paragraph method, so generally in vogue in analogous publications in the English and other languages, are combined with the more consecutive and eliminating characteristics of the historical; the latter is a much more prominent feature in the present volume than in any of its predecessors, and special attention will be devoted to it in the future.

A list of some of the more prominent publications on scientific subjects which have appeared during the past year has been prepared for this volume. In the selections. for this list we have been chiefly guided by the commendatory notices which have appeared in the more prominent scientific journals of the day, and references to the pages of the journals wherein the works catalogued are reviewed are given. As the journals in question are generally easily accessible, the reader is thus furnished with a trustworthy guide in his selection of books.

SPENCER F. BAIRD.

SMITHSONIAN INSTITUTION, WASHINGTON, March 28, 1876.

(a.) MATHEMATICS AND THEORETICAL MECHANICS,

The Early Use of the Decimal Point, 1; Tables of Elliptic Integrals, 1;

the Reduction of Elliptic Integrals, 2; New Formula for Determining the

Altitude from Barometric Observations, 2; the Trisection of an Angle, 2;

Properties of Prime Numbers, 4; Applications of Peaucellier Cells, 4;

Hamilton's Equation of Motion, 4; on the Solution of Numerical Equa-
tions, 6; Divisibility by Seven, 31; the Computation of the Areas of Ir-
regular Figures, 33; Properties of the Tetradron, 35.

(b.) ASTRONOMY.

Interstellar Space: The Density of the Luminiferous Ether, 6.-Stars:

A Fine Double Star, 6; Herschel's Catalogue of Double Stars, 7; Orbit of

a Double Star, 8; the Orbit of the Double Star "Mu Bootis," 8; Spectra

of the Faint Stars, 9; on the Scintillation of the Stars, 9; Photographs of

Stellar Spectra, 11; Orbit of the Double Star 42, Coma Berenices, 36;

Method of Constructing Charts of Stars, 37; on the Rectilinear Relative

Motion of the Components of the Star 61 Cygni, 38; the Triple Star Zeta

Cancri, 38; on the Observation of Variable Stars, 59.-The Solar System:

On the Chemistry of the Solar System, 40.-The Sun: Agreement of

Secchi's Views with Professor Langley's, 11; White Lines in the Solar

Spectrum, 11; the Structure of Solar Spots, 10; Zöllner's Theory of the