610 



SCIENCE. 



[N. S. Vol. XVII. No. 433. 



during the six and one half minutes of the 

 eclipse. Nevertheless, when the negatives 

 were developed it was found that the ob- 

 servations were extremely satisfactory, 

 valuable results having been secured with 

 all of the ten instruments. 



The photographs obtained with the for- 

 ty-foot camera are admirable, the general 

 features of the inner and middle corona 

 being shown as well as if there had been 

 no clouds. A most interesting and unique 

 coronal disturbance was recorded in posi- 

 tion angle 60°. A comparison of the solar 

 photographs with those made on the days 

 preceding and following the date of the 

 eclipse by English observers in India, led 

 to the very important conclusion that the 

 coronal disturbance was situated imme- 

 diately above the prominent and only sun- 

 spot visible on those days. 



The speetrographic and polarigraphic 

 results were completely successful, per- 

 haps more so than would have resulted 

 from an unobscured eclipse. They estab- 

 lished that the spectrum of the outer co- 

 rona is identical with that of ordinary 

 sunlight, and therefore that the light of 

 the outer corona is not inherent, but is re- 

 flected light originating in the main body 

 of the sun ; that the spectrum of the inner 

 corona is continuous, and therefore is not 

 reflected sunlight; that the outer corona 

 shows the strong polarization effects that 

 would be expected to result from its char- 

 acter as reflected light; and that the inner 

 corona gives only slight evidence of po- 

 larization, as would be expected from light 

 largely of an inherent character. 



Mr. Perrine has carefully examined the 

 plates secured with four cameras for the 

 purpose of detecting any possible intra- 

 Mercurial planets. The instruments gave 

 splendid definition, and in the unobscured 

 areas surrounding the sun stars down to 

 the ninth magnitude were recorded. The 

 search was highly satisfactory for more 



than two thirds of the area under examina- 

 tion, but the clouds prevented complete 

 success in the remaining one third. All 

 the images on the plates were identified 

 as those of known stars. 



The discovery of the minor planet Eros 

 in 1898, and the recognition of the un- 

 usual opportunities offered by it for an 

 improvement in our knowledge of the dis- 

 tance of the sun, led to the organization 

 of a cooperative scheme on the part of 

 forty or fifty leading observatories, to 

 secure the necessary observations in the 

 fall of 1900. The Lick Observatory en- 

 tered energetically upon the program out- 

 lined. Astronomer Tucker secured more 

 than two thousand meridian circle observa- 

 tions of the 678 reference stars, required as 

 a basis for the entire problem. The mi- 

 croscopes were read by Dr. R. T. Crawford 

 for about 1,600 of the observations, and 

 he rendered some assistance in the compu- 

 tations, but Mr. Tucker was unassisted 

 in the bulk of the reductions. The prompt 

 completion and publication of this exten- 

 sive piece of work, long in advance of the 

 appearance of results from other observa- 

 tories, called forth many expressions of 

 admiration for the energy and skill of the 

 astronomer in charge. 



Micrometer measures of the position of 

 Eros were obtained by Astronomer Hussey 

 and Assistant Astronomer Aitken, with the 

 thirty-six-inch equatorial. The former 

 made 832 measures in right ascension, and 

 896 in declination; the latter 1,650 in right 

 ascension and 729 in declination. Photo- 

 graphic observations were secured with 

 the Crossley Reflector by Assistant Astron- 

 omer Perrine, assisted by Fellow H. K. 

 Pahner. They include 344 plates on sixty- 

 three nights for accurate meridian places 

 of the planet; 511 plates on thirty-seven 

 nights for a parallax; 110 charting and 

 connecting plates; total, 965 plates, of 

 which 854 contain short exposures for 



