248 OBITUARY. 



Mr. Dunkin formed one of the Admiralty party, who 

 proceeded to Norway and Sweden to observe the solar eclipse, 

 on 28th July, 1851. His station was at Christiania, near the 

 northern boundary of the shadow-path, where the duration of 

 totality was 2^ minutes. The sky during the progress of the 

 eclipse was more or less cloudy, but at the critical moment the 

 clouds cleared away sufficiently to enable the observers to note 

 positions of three rose-coloured protuberances, and also faint 

 indications of the solar corona. 



In 1853 and 1854 Mr. Dunkin was the Greenwich observer 

 in the determinations of the difference of longitude between the 

 Royal Observatory and the Observatories of Cambridge, Brussels, 

 and Paris ; the opposite observers being, respectively, Mr. (now 

 Sir Charles) Todd, M. Bouvy, and M. Faye. Each of the 

 operations was divided into two sections, in the second of which 

 the observers were interchanged. In 1862 an important and 

 far more difficult operation was arranged by the Astronomer 

 Royal for the determination of the difference of longitude 

 between the Royal Observatory and a station near Knightstown, 

 in the island of Valencia, co. Kerry, Ireland. Mr. Dunkin had 

 charge of the observations at the Irish station. 



In the autumn of 1854, Mr. Dunkin had the control of the 

 Astronomer Royal's pendulum experiments made in the Harton 

 Colliery, near South Shields. These observations were under- 

 taken with the object of determining the mean density of the 

 earth, by ascertaining the different effects of gravity on the 

 vibrations of a free pendulum when mounted on the surface or 

 at the bottom of a deep mine. 



Mr. Dunkin took a great interest in investigating the 

 relative values of the probable error of a transit of a star by 

 the eye-and-ear and chronographic methods, and of the various 

 kinds of personalty in astronomical observations, especially in 

 observing transits of the limbs of the sun and moon, and in 

 zenith distance observations. Several papers by him on these 

 subjects may be found in the "Memoirs" and "Monthly Notices" 

 of the Royal Astronomical Society. An important paper " on 

 the Movement of the Solar System in Space, deduced from the 

 Proper Motions of 1167 Stars" was presented to that society on 



