A. MATHEMATICS AND ASTKONOMY. 21 



tions at these stations were divided into those preliminary 

 to and succeeding the eclipse, and those made during the 

 eclipse, to which should be added the magnetic and meteoro- 

 logical observations. During the eclipse proper, besides the 

 exact observation of the time of befnnnino; and ending of 

 each phase, a special interest centres in the appearances ob- 

 served during the few minutes of total obscuration. The 

 attempts to photograph the various features of the eclipse 

 seem to have been quite successful, having been accomplish- 

 ed by means of an instrument of large dimensions by Dall- 

 meyer, the same which had been used by De La Rue in Spain 

 in 1860. By virtue of the necessity for a subdivision of la- 

 bor during the brief interval of the duration of the total 

 eclipse, the chronometric determination of the time w T as as- 

 signed to Professor Donati ; the photometric operations were 

 conducted by Professor Secchi. The polarization of the so- 

 lar corona was observed by Professor Blaserna, who made 

 use of a Savart j3olariscope, in which the tourmaline plate 

 was replaced by a Nichols prism. His results were among 

 the most interesting that have been recorded in connection 

 with the solar phenomena. He states that the influence of 

 the terrestrial atmosphere was feeble ; that the solar corona 

 was strongly polarized ; and that the plane of polarization 

 was in the direction of a tangent to the limb of the sun. 

 These positive results from the hands of an experienced ob- 

 server are especially interesting, in consideration of the nu- 

 merous contradictory and fruitless observations made by 

 many others. The observations of the protuberances seen 

 during the period of totality were assigned to Professor 

 Denza, who was armed with a spectroscope attached to a 

 large refracting telescope constructed by Merz, of Munich. 

 The meteorological and magnetic observations were also un- 

 der the general care of Professor Denza, and embraced every 

 element of terrestrial and atmospheric physics that could be 

 observed. It is well known that he has recently deduced an 

 apparent dependence of certain changes in magnetic instru- 

 ments upon the occurrence of this eclipse. 



The preceding observations were made at Augusta, in Sic- 

 ily. The other station occupied by the Italian astronomers 

 was Terra Nova, at which place Professor Tacchini had gen- 

 eral charge of the observations, assisted by numerous subor- 



