ASTRONOMY. 197 



■way. The work comes at exactly the right time, and satisfactorily fills 

 its place. 



A very elaborate paper on the polarization of the corona, by Dr. 

 Schuster, is published in the M. i^. for December, 1879. This paper 

 shows how combined measures of the polarization at different distances 

 from the Sun, and of the decrease in intensity of the total light of the 

 corona with increasing distance from the Sun, may inform us in what 

 way the scattering matter is distributed in the solar atmosphere, what 

 part of the light sent out by the corona is due to scattering matter, and 

 whether the latter is projected outwards from, or is falling into the Sun 

 from outside. 



Mr. Leonard Waldo has published a report on the observations of 

 the solar eclipse of July, 1878, made at Fort Worth, Texas, by a party of 

 which he was the leading- member.* An attemj)t was made to obtain 

 photographic evidence of the polarization of the corona by inserting a 

 double-image prism between the lenses of a camera. The photographs 

 obtained in this way were examined by Prof. Pickering, who found 

 inequalities in them, which, as far as they go, tend to indicate tangential 

 polarization ; but in the opinion of Dr. Hastings the evidence is not 

 conclusive. The inner corona was seen by Mr. Seagrave about 30^ be- 

 fore totality. Mr. Pulsifer, using a ten-prism spectroscope attached 

 to a four-inch Clark refractor, and keeping the slit tangential, observed 

 the reversal of the Frauenhofer lines at the commencement of totality. 

 From the length of these lines, which only reached one-third across the 

 spectrum, the tangential thickness of the reversing layer was found, and 

 from this Mr. Pulsifer infers its minimum height above the photo- 

 sphere to be 521 miles. The C line was not shortened like the others, 

 but extended right across the spectrum. 



The Naval Observatory at Washington, has published the reports 

 relating to the total solar eclipses of 1878 and 1880 in a large 4P 

 volume of 41G pp., accompanied by 25 wood cuts of drawings made 

 by observers and 30 chromohthographed plates. This important vol- 

 ume has been edited by Prof. Harkness, who has provided a com- 

 plete index of persons (4 pages) and index of subjects (G pages), besides 

 a table of contents of 9 pages. It is worth while to mention these 

 indexes, because their presence seems to be an indication that men 

 of science are beginning to avail themselves of devices which have 

 long been considered indispensable to even the simplest literary per- 

 formance, and which in the nature of things are still more necessary to 

 technical and scientific writings. This special work, however, deserves 

 a careful review for many reasons, principally in that it is decidedly the 

 most important contribution which has ever been made to the literature 

 of any single eclipse, not excepting the memoirs of De la Eue, of La- 

 MONT, and the report of the Austrian Commission on the Aden eclipse. 



* Cambridge, Mass. (J Wilson and Sou), 1879. 4to. 



