60 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 

 PHOTOGRAPHS OF THE SOLAR CORONA. 



Professor Zenger, of Prague, announces a success which, if 

 confirmed, will be of high importance. By using a new form 

 of " achromatic lens in combination with mirrors of large 

 aperture and very short focal length, so as to reduce the 

 focal length to four times the aperture," Professor Zenger 

 claims to have photographed the solar corona with the pro- 

 tuberances on it, and also to have examined the corona 

 through the telescope. He describes its appearance to the 

 eye as " a bright circular ring ... on an average one min- 

 ute in height, and only in exceptional cases of nearly two 

 minutes, and an eccentricity amounting to only two or three 

 seconds of arc." 



DISTRIBUTION OF PUBLIC TIME. 



The importance of this subject, which is now attracting 

 general attention, will render the subjoined list of the vari- 

 ous time-balls, time-guns, etc., of the world, valuable. It 

 has been compiled from the best sources available, but cor- 

 rections and additions will no doubt be necessary in many 

 cases, as the materials for the compilation are somewhat 

 limited. 



List of Time-l)alls^ Time-signals^ etc. 



EUROPE. 



Uelsingfors. There is a time-ball dropped at noon at the 

 observatory, and a gun fired either on the guard-ship or 

 ashore. 



Bergen. A time-ball is dropped daily at noon. 



St. Petersburg. Several public clocks in the city are con- 

 trolled from the Pulkova Observatory, and a time-ball (w 

 time-gun) makes a signal at noon daily. 



Kiel. Time-ball {or time-gun) for shipping. 



Dantzig. Time-ball at local noon and at Greenwich 1^ 



Hamburg. Time-ball {or time-gun) for shipping. 



Paris. The public clocks are controlled from the Paris 

 Observatory. 



Lisbon. A time-ball is dropped from the observatory at 

 1^^ Lisbon mean time, and one is dropped simultaneously on 

 the south side of the river from Prayal flag-staft'. 



