162 



SCIENCE 



[N. S. Vol. XXVII. No. 6S3 



graph of the Yerkes Obser-catory : Edwin B. 

 Feost and Philip Fox. 



10. A Graphic Method for the Determination of 

 the Orbit of a Spectroscopic Binarjf: Kuht 

 Laves. 



11. tieio Tables for the Time of Sight Correction 

 of the Earth's Orbital Motion: Kukt Lates. 



12. A Generalized Theory of Integral Equations: 

 W. D. Caibns. 



13. On the Theory of Order, Static and Nascent: 

 G. B. Halsted. 



14. Singular Points in the Approximate Develop- 

 ment of the Perturbative Function: F. W. 

 Eeed. 



15. On a Certain Class of Algebraic Translation- 

 surfaces: John Eisland. 



16. Matrices not belonging to Groups: Arthur 

 Ranum. 



17. A Note on Interest on Reserve from Items 

 Computed for the Uniform Report Blank: C. 

 H. Beckett. 



18. On Asymptotic Isothermic Surfaces: A. E. 

 Young. 



19. Some Questionable Terms mid Definitions 

 used in Elementary Mathematics: G. A. Miller. 



20. The Photographic Determination of Star- 

 colors and their Relation to Spectral Type: 

 J. A. Parkhurst and F. C. Jordan. 



21. On the Detection of the Eruptive Promi- 

 nences on the Solar Disk: Philip Fox. 



22. An Investigation of the IiO-inch Objective at 

 the Yerkes Observatory: Philip Fox. 



23. The Function of a Color Filter and of Cer- 

 tain Plates in Astronomical Photography: R. 

 J. Wallace. 



24. The Vertical Ccelostat or " Tower " Telescope 

 of the Mt. Wilson Solar Observatory: G. E. 

 Hale. 



25. Preliminary Results of a Comparative Study 

 of the Spectra of the Limb and the Center of 

 the Sun: G. E. Hale and W. S. Adams. 



26. A Simple Method for Reducing Spectro- 

 grams: Frank Schlesingeb. 



27. On the Probability of the Near Approach of 

 Two Stars and on Relative Problems in the 

 Sidereal Universe: F. R. Moulton. 



In the absence of their respective authors 

 the papers of Doctors Cairns, Halsted, 

 Lovett and Ranum were read by title, and 

 the paper by Professor Schlesinger was 

 read by Mr. Fox. All the other papers in 

 the above list were read by their authors, 

 and the abstracts which follow bear num- 



bers corresponding to these of the titles in 

 this list. 



1. These observations refer to recent 

 work at the Yerkes Observatory on stars 

 having interesting spectra and include 

 some new spectroscopic binaries. 



2. In this second paper by Professor 

 Frost he described the satisfactory experi- 

 ence with the instruments mentioned in the 

 title. Although they have been in use for 

 only a few months, their merits appear 

 fully established. 



3. This comet became a large one, visible 

 to the naked eye in July and August. 

 With the eye alone, the maximum length 

 of the tail was about 17°, but the photo- 

 graphs showed that it really attained a 

 length of some 25°. 



The comet was photographed on every 

 possible occasion with the Bruce photo- 

 graphic telescope of the Yerkes Observa- 

 tory. Though these pictures showed very 

 rapid changes in the form and general 

 structure of the tail, they did not reveal 

 any new phenomena. 



The most interesting feature was a large 

 mass of cometary matter that was thrown 

 off from the head about July 11. Photo- 

 graphs made of the comet by M. Quenessett 

 in France, by the writer at the Yerkes Ob- 

 servatory and by Mr. Duncan at the Lick 

 Observatory on that date showed that this 

 mass, though it was left behind by the 

 comet, partook of its sunward motion, for 

 it drifted slowly towards the sun through- 

 out the period covered by the photographs. 

 Professor Barnard exhibited a number of 

 lantern slides which showed the changes in 

 the tail. 



4. In liLs second paper Professor Bar- 

 nard gives new nebulous stars and nebu- 

 losities sho^vn on photograplis made by him 

 in the pure atmosphere of Mt. "Wilson in 

 the summer of 1905. Hfi also showed that 

 nebulffi M 17, M 16 and M 8 have wide 

 extensions of feeble nebulosity that greatly 



