616 



SCIENCE. 



[N. S. Vol. I. No. 22. 



On ike Spectrograpliic Performance of the Thirty- 

 inch Pulkoioa Refractor : A. Belopolsky. 

 The work of the great refractor with a 

 spectrograph not well adapted to it com- 

 pares unfavorably with that of the new 

 thirteen-inch photographic telescope. 



Note on the Spectrum of Argon : H. F. ISTewall. 



A line spectrum obtained last year under 

 peculiar conditions of low pressure has been 

 identified as that of argon. A glass bulb 

 was sealed to a mercury pump and the air 

 exhausted. Two photographs, with an ex- 

 posure for each of thirty minutes, differed 

 in that the second showed the nitrogen 

 bands much weaker than the first, besides 

 containing lines since identified as those of 

 argon. 

 Preliminary Table of Solar Spectrum Wave- 



Lengths, V: Henet A. Kowland. 



The table is contiaued from X 4414 to k 

 4674. 

 On Martian Longitudes: Percival Lowell. 



A series of observations on the positions 

 of thirty-six points on Mars with a view to 

 the construction of a map. A discrepancy of 

 five degrees between present longitudes and 

 those determined by Schiaparelli in 1879 

 suggests that the received time of rotation 

 of the planet is too small. 

 A Combination Telescope and Dome: A. E. 



Douglass. 



The article describes a novel plan of 

 mounting a telescope within a hollow sphere 

 supported like an ordinary globe, but with 

 much of the weight taken off from the sup- 

 ports by floating the sphere iu water. The 

 plan is the result of an effort to reduce the 

 instability of the usual mounting by flota- 

 tion, and the application of the motive power 

 as far as possible from the axes of rotation. 

 Stars Having Peculiar Spectra; Eleven New 



Variable Stars : M. Fleming. 



Some Arequipa photographs show eleven 

 peculiar star spectra and eleven new vari- 

 ables. 



A Spectroseojne Proof of the Meteoric Constitu- 

 tion of Saturn's Rings : James E. Keeler. 

 The spectrum of the planet was photo- 

 graphed with the sHt parallel to the major 

 axis of the rings. The incUnation of the 

 spectral liaes of the ansse show that the 

 inner part of the ring is moving faster than 

 the outer portion, which would not be the 

 case were the rings moving as a solid. The 

 indicated velocities of the difierent parts 

 satisfy Kepler's third law. 

 Remarks on Professor Pickering's 'Comparison 

 of Photometric Magnitudes of the Stars,' in A. 

 N. 3269 : G. Muller and P. Kempf. 

 A criticism of the Cambridge catalogues, 

 translated from the Astronomische Nach- 

 richten. 

 The Short Wave-Lengths of the Spark Spectrum 



of Aluminium: C. Eunge. 

 A Large Eruptive Prominence; On a Photo- 

 graphic Method of Determining the Visibility 

 of Interference Fringes in Spectroscopiic Meas- 

 urements ; Note on the Exposure Required in 

 Photographing the Solar Corona Without an 

 Eclipse: George E. Hale. 

 Terrestrial Helium (?). 



A Large Reflector for the Lick Observatory: 

 Edward S. Holden. 



S. B. Barrett. 



NEW BOOKS. 



The Natural History of Plants; their Forms, 

 Ch'oivth, Reproduction and Distribution. 

 Fi'om the German of Anton Kerner von 

 Marilawn, by F. W. Oliver, with the as- 

 sistance of Marian Busk and Mart F. 

 Ewart. With almost 1,000 original 

 wood-cut illustrations and 16 plates in 

 colors. New York, Henry Holt & Co. 

 1895. 40, Vol. I., in two parts. Pp. 777. 

 Price 17.50. 



Twentieth Annual Report of the Secretary of the 

 State Board of Health of the State of Michigan. 

 Lansing, Kobert Smith & Co. 1894. Pp. 

 cxlvi -f 416. 



