26 Astronomy 



No. 9. HILL, GEORGE WILLIAM. The Collected Mathematical Works of George 



William Hill. Quarto, 4 vols. Published 1907. Price $2.50 per vol. 

 Vol. 1, 381 pages; vol. 2, 346 pages; vol. 3, 577 pages; vol. 4, 466 pages. 



The above volumes comprise the works of Dr. Hill in dynamical astronomy, 

 mathematical physics, and mathematics complete up to 1907. The memoirs, 84 

 in number, are arranged chronologically, the date of the earliest being 1859. The 

 last five memoirs appear here for the first time. The first volume contains a 

 portrait of the author and an introduction by Henri Poincare. 



No. 45. FURNESS, CAROLINE E. Catalogue of Stars within Two Degrees of the 

 North Pole, Deduced from Photographic Measures. Octavo, 85 pages. 

 Published 1905. Price $0.50. 



This is an extension of the Star Catalogue presented in Publication No. 1 of 

 the Vassar College Observatory, which gave a catalogue of stars within one degree 

 of the North Pole, whereas the present publication extends the catalogue to two 

 degrees from the North Pole. Both catalogues are based upon photographs taken 

 by Professor Donner, of Helsingfors, Finland, a series of twelve negatives being 

 under consideration, which together include all the stars of less than two degrees 

 polar distance. The present paper treats first of the measurement and reduction 

 of 89-degree plates, with a preliminary catalogue of the stars found thereon ; second, 

 of the inter-adjustment of the several plates and their combination with the former 

 catalogue; and third, of the formation of the final catalogue of all the stars found 

 on twelve plates. 



No. 10. NEWCOMB, SIMON. Contributions to Stellar Statistics. On the Position of 

 the Galactic and Other Principal Planes toward which the Stars Tend 

 to Crowd. Quarto, 34 pages. Published 1904. Price $0.25. 



A principal inquiry in the above paper is to determine the position both of the 

 galaxy itself and of the planes toward which the stars appear to crowd, irrespective 

 of the existence of the galaxy. Some previous inquiries might appear to show 

 that the tendency to crowd toward the galaxy is well marked even in the case of 

 stars visible to the naked eye, but the present investigation shows that this tendency 

 is less marked when the galactic stars are considered as forming a collection separate 

 from the others. 



No. 72. NEWCOMB, SIMON, assisted by FRANK E. Ross. Investigation of Inequali- 

 ties in the Motion of the Moon produced by the Action of the Planets. 

 Quarto, vm-f 160 pages. Published 1907. Price $1.00. 



The principal object of the above work was the hope of explaining by gravi- 

 tational theory the observed variations in the mean longitude of the moon, shown 

 by more than two centuries of observations to exist, but not yet satisfactorily ac- 

 counted for. The work naturally divides itself into four parts. One of these 

 treats of the theory of the subject, including under this head not only the general 

 equations, but the numerical details on which all the computations are based. In 

 this part the fundamental quantities are reduced to products of two factors, one 

 of which depends upon the coordinates of the planet; the other upon the geo- 

 centric coordinates of the moon. The first factors, termed planetary, are numeri- 

 cally developed in Part II. This development falls into two parts, one treating the 

 direct action of the planet, the other the indirect action through the sun. In Part III 

 is found the numerical development of the factors depending upon the moon alone, 

 and of the partial derivatives as to the lunar elements. In Part IV are presented 

 the combinations of these two factors and the final results of the work. 



No. 33. PARKHURST, J. A. Researches in Stellar Photometry. Quarto, 192 pages, 

 13 plates, 39 text figures. Published 1906. Price $2.00. 



The equalizing-wedge photometer is investigated and applied to stellar pho- 

 tometry in measuring the comparison stars, from 6th to 16th magnitude, tor 

 twelve variable stars, using telescopes of 6, 12, and 40 inches aperture at the 

 Yerkes Observatory. The fields, including the stars measured, are shown by half- 

 tone charts from photographs taken with the 2-foot reflector. Light-curves of the 



