ASTRONOMY. . 391 



graphs will be given later; for they require a thorough examination 

 since they record many most interesting phenomena. I will simply say, 

 at present, that these photographs show a coroua more extended than 

 that given by telescopic examination, and that the phenomena appeared 

 well defined and steady during the duration of totality. 



"Luminous intensity of the corona. — I had prepared a photometric 

 measure by photography of the luminous intensity of the corona. 

 This experiment showed that at Caroline Island the illumination given 

 by the corona was greater than that of the full moon. The exact num- 

 bers will be given later. It should be noted that this is the first time 

 that an exact measure of the luminous intensity of this phenomenon 

 has been made." 



The remainder of the report gives an account of the return journey 

 of the members of the expedition. They visited the volcano of Kila- 

 nea, on the island of Hawaii, and passed a night in the crater on the 

 edge of the lava lake. Mr. Jaussen made some experiments, which, 

 he states, "shows some curious coir cidences between these volcanic 

 phenomena and those of the solar surface. I was able, also, to obtain 

 the spectrum of the flames which issue from the lava, and to establish 

 in them the presence of sodium, hydrogen, and carbureted compounds." 

 — (Professor W. Upton in Science, November 2.) 



The total solar eclipse of August 28, 29, 188G. — This great eclipse is a 

 return of that of August 17, 18, 1868, which was extensively observed 

 in the Bombay and Madras Presidencies and in other parts of its track 

 from Aden to Torres Straits. In 1886 the track of the central line will 

 be mainly over the Atlantic Ocean, and at that portion of it where the 

 duration of totality is longest it will not be observable on land. It is 

 therefore of interest to examine the possible conditions of observation. 

 In deducing the results which follow, the places of the sun and moon 

 have been taken from the Nautical Almanac, where Newcomb's correc- 

 tions to Hansen's Lunar Tables are introduced. As will be seen from 

 the Ephemeris, the central eclipse commences in longitude 79° 46' west 

 of Greenwich, and latitude 9° 48' north, off Colon, in the Isthmus of 

 Panama, thence running in the direction of the Windward Islands 

 across the northern parts of New Granada and Venezuela; passing 

 over the island of Granada, it traverses the Atlantic, and meets the 

 coast of Africa in the Portuguese possessions, not far from St. Philip 

 de Benguela, and crossing South Africa to Sofala, it ends on the east 

 coast of Madagascar. At Cartagena the duration of totality is 3 m . 2 8 , 

 with the sun at an altitude of 5° ; at Maracaibo the duration is 2 m . 57 8 , 

 with the sun 9° above the horizon. The southern extremity of the 

 island of Grenaada will have the most advantageous conditions for ob- 

 servation, having regard to length of totality and accessibility. The 

 total eclipse begins there at 7 b ll m , s A. m. on August 29, and con- 

 tinues 3 ,B 42 s , the sun being at an altitude of 20°; at the northern 



