FOR DETERxMINlNG THE MEAN DENSITY OF THE EARTH. 
307 
the night, Mr. Dunkin and Mr. Ellis, from the end of 
Swing 47 to the beginning of Swing 50. 
1854. October 13. — Observers for the day, Mr. Pogson and Mr. Rumker, from the 
end of Swing 50 to the end of Swing 52. The Second 
Series was closed at the end of Swing 52. 
October 14. — Mr. Dunkin, with the assistance of Mr. Ellis and Mr. Pogson, 
interchanged the pendulums. 
October 16. — The Third Series commenced with Swing 53. Pendulum 1821 
above. No. 8 below. Observers for the day, Mr. Criswick 
and Mr. Simmonds, from the beginning of Swing 53 to the 
beginning of Swing 55 : for the night, Mr. Rumker and 
Mr. Pogson, from the end of Swing 55 to the beginning 
of Swing 58. 
October 17 . — Observers for the day, Mr. Ellis and Mr. Dunkin, from the 
end of Swing 58 to the beginning of Swing 61 : for the 
night, Mr. Simmonds and Mr. Criswick, from the end of 
Swing 61 to the beginning of Swing 64. 
October 18. — Observers for the day, Mr. Pogson and Mr. Rumker, from the 
end of Swing 64 to the beginning of Swing 67 ; of which 
the end was observed by Mr. Dunkin and Mr. Ellis. 
The Third Series was closed at the end of Swing 67. 
Mr. Dunkin and Mr. Ellis interchanged the pendulums 
at night. 
October 19. — The Fourth Series commenced wdth Swing 68, begun by 
Mr. Dunkin and Mr. Ellis. Pendulum No. 8 above, 
1821 below. Observers for the day, Mr. Criswick and 
Mr. Simmonds, from the end of Swing 68 to the beginning 
of Swing 71 : for the night, Mr. Rumker and Mr. Pogson, 
from the end of Swing 71 to the beginning of Swing 74. 
October 20. — Observers for the day, Mr. Dunkin and Mr. Ellis, from the 
end of Swing 74 to the beginning of Swing 77 : for the 
night, Mr. Simmonds and Mr. Criswick, from the end of 
Swing 77 to the beginning of Swing 80. 
October 21. — Observers for the day, Mr. Pogson and Mr. Rumker, from the 
end of Swing 80 to the beginning of Swing 82 : the end of 
Swing 82 was observed by Mr. Dunkin and Mr. Pogson. 
The Fourth Series and the whole operation closed with 
Swing 82. 
October 22. — I arrived from Greenwich. 
October 23. — I inspected the instruments in position, and dismounted them. 
October 24. — The instruments were mounted in the Central Hall of South 
2 s 2 
