analogy between the curves of sun-spot frequency and the light changes in variable stars. She believes that "the maximum of spots in the sun corresponds with the maximum of light in stars, and vice versa." Accepting Professor LOCKYER'S theory that sun-spots are due to down-rushes of cooled matter upon the photosphere, she considers that the falls are vastly increased in number at spot-maximums, and the intense heat, accompanied by the development of great electrical force, account for the changes in brilliancy and spectrum. Seemingly, in order to connect this explanation with that given for temporary stars, the spot period is supposed to be controlled by an attendant body revolving in an orbit of dimensions determined by the atmospheric extension of the star. Tidal effect is also hinted at, and it would be a strange chance if this all-embracing explanation did not contain some grains of truth. This, however, does not vitiate the force of the statement that "the time has not come to formulate a theory of stellar variability" (p. 125). As to short-period variables, they seem to offer even greater difficulties than those of longer period, with the exception, of course, of the Algol type, which Dr. VOGEL'S spectrographic investigations have fully explained.

The interesting descriptive matter contained in the rest of the book calls for no particular discussion here, but it can be highly recommended as giving a valuable account of the general topics of stellar astronomy. The chapter on the colors of the stars renders very certain the belief that methods of observation much more reliable than those generally employed in the past, must precede conclusions of very great value. Double stars, variable doubles, stellar orbits and multiple stars occupy successive chapters. The Pleiades deservedly claim a chapter to themselves, before star clusters in general are taken up, and the results of recent investigation are entertainingly introduced by references to the legendary importance of this celebrated group. The next three chapters are devoted to the nebulæ, and reproductions of Mr. ROBERTS' photographs form excellent illustrations, with the unfortunate exception of the Great Nebula in Andromeda, which should have been the best of all. In the discussion of the nature and changes of the nebula the importance of the physical analogy between comets and nebulæ is pointed out, and it is insisted that electricity is involved as the illuminating power. This is by no means impossible, but it it hardly time to say that the nebular spectrum "probably includes no element of truly continuous

light" (p. 296). The distances of the stars, translation of the solar system, proper motions, the Milky Way, status of the nebulæ and the construction of the heavens, are the subjects treated of in the remaining portion of the work, and there are six valuable tables in the appendix.

In spite of its few defects, Miss CLERKE is to be congratulated upon a book which is excellent in the main. A fair discrimination, combined with a wide range of information and an attractive style, seem to be the chief elements in her deserved success.

KENWOOD PHYSICAL OBSERVATORY,

CHICAGO, March 21, 1891.

BY-LAWS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC.*

ARTICLE I.

This Society shall be styled the ASTRONOMICAL SOCIETY OF THE PACIFIC. Its object shall be to advance the Science of Astronomy, and to diffuse information concerning it.

ARTICLE II.

This Society shall consist of Active, Life, Corresponding and Honorary members, to be elected by the Board of Directors.

I. Active members shall consist of persons who shall have been elected to membership and shall have paid their dues as hereinafter provided.

2. Life members shall consist of persons who shall have been elected to life membership and shall have paid $50 (fifty dollars) to the Treasurer of the Society.

3. Corresponding members shall consist of persons not residing on the Pacific Coast, who shall have been elected as such.

4. Honorary members shall consist of persons specially distinguished for their attainments in Astronomy, not to exceed thirty in number, who shall have been elected as such.

Corresponding and Honorary members shall pay no dues, shall not be eligible to office, shall have no votes, and shall receive the Publications of the Society.

5. A certain number of Observatories, Academies of Science,

* For the convenience of new members, the By-Laws now in force are here printed.

Astronomical Societies, Institutions of learning, etc., not to exceed one hundred, shall be designated by the Board of Directors as Corresponding Institutions, and they shall receive the Publications of this Society in exchange or otherwise.

ARTICLE III.

At each annual election there shall be elected a Board of eleven Directors, and a Committee on Publication, consisting of three members. The officers of this Society shall be a President, three Vice-Presidents, two Secretaries and a Treasurer. The Directors shall organize immediately after their election, and elect from their number the officers of the Society. They may also appoint a Librarian, and such other assistants as may be required. The Directors shall fill by appointment any vacancies which may occur after the annual election.

The Library of the Society shall be kept in San Francisco, and shall be open to the use of all the members.

ARTICLE IV.

The President, or, in his absence, one of the three Vice-Presidents, or, in the absence of both the President and the Vice-Presidents, any member whom the Society may appoint, shall preside at the meetings of the Society. It shall be the duty of the President to preserve order, to regulate the proceedings of the meetings, and to have a general supervision of the affairs of the Society. The President is ex-officio a member of all Committees of the Board of Directors.

ARTICLE V.

The Secretaries shall keep, and have the custody of, the records; they shall have the custody of all other property of the Society, excepting the money thereof; they shall give timely notice of the time and place of meetings; they shall keep in books a neat and accurate record of all orders and proceedings of the Society, and properly index them; they shall conduct the correspondence of the Society; they shall preserve and index the originals of all communications addressed to the Society; and keep a copy of all their letters, properly indexed; and they shall prepare for publicacation an accurate summary of the transactions of the Society at each of its meetings.

ARTICLE VI.

The Treasurer shall receive and deposit in such bank as may be designated by the Directors, to the credit of the Society, all donations and bequests of money and all other sums belonging to the Society. He shall keep an account of all money received and paid by him, and at the annual meetings shall render a particular statement of the same to the Society. Money shall be paid by him only on the written order of the Finance Committee of the Board of Directors. He shall give such bonds as may be required by the Board of Directors.

ARTICLE VII.

Candidates for active or life membership may be proposed by any member of the Society to either of the Secretaries, in writing. A list of such candidates shall be certified to the Board of Directors by the Secretaries at each of their meetings, in writing. A majority (not less than three) of the Directors present at any such meeting shall be required for election.

ARTICLE VIII.

Each active member shall pay an annual subscription of five dollars, due on the first of January of each year, in advance. Each active member shall, on his election, pay into the Treasury of this Society the sum of five dollars, which shall be in lieu of the annual subscription to the first of January following his election, and in lieu of an initiation fee. No one shall be deemed an active member, or receive a diploma, until he has signed the register of members, or accepted his election to membership in writing, and paid his dues for the current year. Any member may be released from annual dues by the payment of fifty dollars at one time, and placed on the roll of life members by the vote of the Board of Directors. Any failure on the part of a member to pay his dues within six months after the time the same shall have become payable, shall be considered equivalent to a resignation.

ARTICLE IX.

The annual meeting of this Society shall be held on the last Saturday in March at eight o'clock, P. M., at the rooms of the Society in San Francisco; and meetings shall be held for the ordinary transactions and purposes of the Society, as follows:

Meetings shall be held in the Library of the Lick Observatory,

Mount Hamilton, at a suitable hour on the second Saturday of June and the first Saturday of September; and meetings shall be held in the rooms of the Society, in San Francisco, at eight o'clock P. M., on the last Saturdays of January, March and November.

A special meeting may be called by the President, or, in his absence or disability, by one of the Vice-Presidents, or, in the absence or disability of both the President and the Vice-Presidents, by the Secretary, on the written requisition of ten active or life members; and the object of such meeting shall be stated in the notice by which it is called.

The annual election shall be held on the day of the annual meeting, between the hours of 8:15 and 9 P. M.

Only active and life members shall be permitted to vote at any meeting of the Society, and no one shall vote who has not paid all his dues for past and current years. There shall be no voting by

proxy.

ARTICLE X.

Fifteen active or life members shall be a quorum for the transaction of business.

ARTICLE XI.

No papers or manuscripts shall be published by the Society without the consent of the Directors. Any motion to print an address, or other paper read before the Society, or any other matter belonging to the Society, shall be referred to the Committee on Publication, who shall report to the Directors. The Committee on Publication may make suggestions to the Directors, from time to time, with reference to the publication of such papers as in their judgment should be published by the Society; and this Committee shall have the care, direction and supervision of the publication of all papers which the Directors may authorize to have published.

Members of the Society shall receive all the publications of the Society free of charge.

ARTICLE XII.

This Society may, by a vote of a majority of all its active and life members, become a branch of an American Astronomical Society, should one be formed.