22 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



dinates. The spectra of the protuberances were observed 

 by himself. Observations on the corona were made, in dupli- 

 cate, by two assistants ; and the observations of the times of 

 contact made, again in duplicate, by two others. The draw- 

 ings and photographs made by the Italian astronomers, as 

 reproduced in the published volume, show the sun's limb to 

 have been remarkably occupied by the familiar red protuber- 

 ances, many of them nearly 100,000 miles high, and of strik- 

 ingly characteristic forms. The corona is depicted as a mass 

 of white light, projecting in spurs, of which ten or twelve 

 are definitely presented, to a distance of at least 500,000 

 miles from the solar surface. In the spectrum of the corona, 

 as observed in Augusta, two bright bands were observed, one 

 in the yellow, the other in the green, corresponding nearly 

 with spaces No. 1250 and No. 1465 of Fraimhofer's scale. 

 Professor Legnazzi records the phenomena of Bailey's beads, 

 and also observed a bright indentation in the edge of the 

 moon, as if the solar light shone through a deep cleft in that 

 body. A similar phenomenon was also recorded by Tacchini, 

 from whose drawing of the appearance of Bailey's beads it may 

 be at once seen that these are really only those portions 

 of the solar limb last visible, and separated from each other 

 by the intervening projecting mountain peaks on the edge 

 of the moon. Accompanying the volume are very fine plates 

 of the appearance of the protuberances as seen by means of 

 the spectroscope, for some days before and after the eclipse 

 in question, together with a magnificent delineation of the 

 appearance of the sun, with its numerous spots, facula?, and 

 protuberances, as observed on the 10th of December; from 

 all of which it would seem as if that month was one of spe- 

 cial activity on the sun's surface. Report of the Italian Com- 

 mission. 



THE APPARENT DIAMETER OF THE SUN. 



Professor Mazzola contributes to the Royal Academy of 

 Sciences of Turin an interesting paper on the determination 

 of the mean diameter of the sun, and upon the numerous causes 

 which introduce error into the observed diameter, and es- 

 pecially the so-called phenomena of irradiation. He shows 

 that the solar diameter deduced from observations of the 

 transit of an inferior planet over the solar disk ought to be 



