ASTRONOMICAL PHENOMENA AND PROGRESS. 



45 



realities. It was hoped that spectrum analy- 

 ses would solve this enigma ; as it was to be 

 the first eclipse at which the science of the 

 spectroscope would be called into play. Kir- 

 choff, De la Rue, Nasmyth, and others, had 

 already, by the agency of this instrument, ob- 

 serving the sun, under the ordinary conditions, 

 become convinced of the existence of incan- 

 descent vaporous matter around that body, to 

 which they had given the name of photosphere. 

 According to their view, it was an envelope of 

 gaseous matter in a state of combustion, at an 

 inconceivably high temperature, by which the 

 most refractory metals would be readily vapor- 

 ized. The inspection of the lurid prominences 

 seen during the eclipse was expected to confirm 

 this generally-accepted theory. 



Full reports of the observations of the various 

 parties have not yet been made public; but 

 the following statements, from official and un- 

 official sources, give the more important facts 

 and inferences with regard to the eclipse. 



An observer of the eclipse, at Aden, writes 

 the following to the London Times : 



As the result of the observations taken by our as- 

 tronomical expeditions in Southern India can only 

 have reached England through the medium of elec- 

 tricity, I avail myself of the passage of a mail steamer 

 to communicate what was observed at this station. 

 The only astronomers and photographers that have 

 come to Aden are all Germans ; three of them, Dr. 

 Weiss, Navigating Lieutenant Ehea, and another 

 gentleman, are Austrians. Their chief object was to 

 make observations on the constitution of the corona. 

 From the observations taken by these gentlemen, 

 there can be no doubt that the problem is now solved, 

 several varied experiments proving in a most conclu- 

 sive manner that the corona merely consists of in- 

 flammable gas in a high state of combustion. The 

 North-German party consisted of one astronomer, Dr. 

 Thiel, of Bremen, and four Prussian photographers 

 working under the direction of Dr. Fritch, of Berlin. 

 This party devoted their attention chiefly to photo- 

 graphing the different phases of the eclipse, having 

 selected Aden as the most likely spot in the zone of 

 " totality" to be free from clouds. 



Several English amateurs, officers of the army and 

 navy,_also contributed their help in recording various 

 experiments according to their respective abilities. 



The weather for a week preceding the eventful 18th 

 had been unusually cloudy for Aden, and prevented 

 the savants who had arrived in the beginning of 

 August from making as many observations as they 

 would have wished. The mornings had been partic- 

 ularly trying, the sun rising between thick banks of 

 purple-gray clouds. 



On the evening of the 17th almost all the rank and 

 fashion of Aden made an exodus to Marshag Hill, the 

 eastern promontory of Aden, where the German 

 party were established with all their instruments. 

 The night was very cloudy, and much anxiety was 

 felt by all interested in the success of the observa- 

 tions. At gray dawn, however, and just before first 

 contact, the banks of cloud separated into broad 

 bands, occasionally shutting out a view of the eclipse. 

 Totality commenced at 6h. 29m. 28s. A. M., and lasted 

 2m. 55s., during which interval a most magnificent 

 view of the phenomena was obtained, and four most 

 successful photographs were taken. 



The only planets and stars observed during the to- 

 tality were V enus, Jupiter, and Sirius, which at once 

 shows that the darkness was not great. 



At the time of totality the height of the tide was 

 7* feet, or for Aden a good average spring tide. The 

 preceding spring tides (about a fortnight before) 



were very bad, the rise and fall not being more than 

 four feet. 



On first separation a most beautifully soft light 

 stole out from behind the moon, lighting up the sea 

 and rocks of Aden in an indescribably beautiful 

 manner. 



The sun was unfortunately -behind a cloud at the 

 final separation, which could not be, therefore, de- 

 termined within a second of time. The times were, 

 of 



Totality 2 55 



The German part^ were delighted with all their ex- 

 periments, and considered themselves amply repaid 

 for their trouble. They had most superb instruments, 

 and were particularly civil and obliging in explaining 

 their use, mechanism, etc. Among the most inter- 

 esting was a photographing telescope, which is made 

 self-acting by means of a most ingenious clock-work 

 mechanism, which, with the help of a simple pendu- 

 lum and endless wheels, is so delicately adjusted as 

 to counteract the motion of the earth, and to keep 

 the telescope rightly fixed on the star or planet dur- 

 ing the ten or fifteen seconds required to receive the 

 impression. 



I send a rough representation of the corona. Its 

 size was accurately measured by means of a telescope 

 with small squares in the diaphragm. These valves 

 can be exactly determined by experiments with the 

 same telescope in the distance between known stars, 

 which can be brought to scale. 



I have the honor to be, sir, your most obedient 

 servant, A. G. 



ADEN, August 21. 



Dr. Weiss, of Vienna, had charge of the 

 Austrian expedition, and selected Aden as his 

 place of observation, chiefly because he had 

 heard much of the usual freedom of the sky 

 there from rain and cloud. The doctor and 

 his assistants observed three large prominences 

 on the border of the moon during the eclipse. 

 The most remarkable of these he describes as 

 sharply defined, finger-shaped, brilliant with 

 the most vivid carmine red, the length of which 

 amounted to about the eighth part of the sun's 

 semi-diameter. Dr. Weiss and Dr. Theodor 

 Oppolzer both made measures of the position 

 and magnitude of each of these protuberances, 

 and the results agreed with each other. At- 

 tention was also directed to the corona, which 

 had a certain general similarity to that seen in 

 Spain at the solar eclipse of July 18, 1860. It 

 could not, however, be perfectly observed, be- 

 cause its longer radiations were for the most 

 part concealed by clouds. Lieutenant Rhea 

 conducted the specti'al investigations. He re- 

 marked, at the occurrence of the totality, a 

 sudden disappearance of all the dark (Fraun- 

 hofer's) lines, the spectrum passing into a so- 

 called continuous one, faint indeed, but still 

 quite distinctly visible. Toward the end of 

 the totality, when a thin veil of cloud had 

 passed over the sun, by which the corona was 

 hidden, whilst the protuberances glimmered 

 through it, the most refrangible part of the 

 spectrum disappeared almost entirely, and 

 there remained a series of red bands, separated 

 from each other by broad dark spaces. 



Major G. F. Tennant, R. E., who had com- 



