306 
MR. AIRY’S ACCOUNT OF THE HARTON EXPERIMENT 
1854. September 30. — I returned to Greenwich, leaving all in the charge of 
Mr. Dunkin. 
October 2. — Observations commenced in the morning with Swing 1. Pen- 
dulum 1821 above, No. 8 below. Observers for the day, 
Mr. Dunkin (above), Mr. Ellis (below), from the begin- 
ning of Swing 1 to the beginning of Swing 3. 
Observers for the night, Mr. Pogson and Mr. Rumker, 
from the end of Swing 3 to the beginning of Swing 6. 
October 3. — Observers for the day, Mr. Criswick and Mr. Simmonds, from 
the end of Swing 6 to the beginning of Swing 9 : for the 
night, Mr. Ellis and Mr. Pogson, from the end of Swing 9 
to the beginning of Swing 12. 
October 4. — Observers for the day, Mr. Rumker and Mr. Criswick, from 
the end of Swing 12 to the beginning of Swing 15 : for 
the night, Mr. Ellis and Mr. Simmonds, from the end of 
Swing 15 to the beginning of Swing 18. 
October 5. — Observers for the day, Mr. Criswick and Mr. Pogson, from the 
end of Swing 18 to the beginning of Swing 21 : for the 
night, Mr. Simmonds and Mr. Rumker, from the end of 
Swing 21 to the beginning of Swing 24. 
October 6. — Observers for the day, Mr. Dunkin and Mr. Ellis, from the 
end of Swing 24 to the end of Swing 26. The First 
Series was closed at the end of Swing 26. 
October 7- — Mr. Dunkin, with the assistance of Mr. Ellis and Mr. Pogson, 
interchanged the pendulums. 
October 9. — The Second Series commenced with Swing 27- Pendulum 
No. 8 above, 1821 below. 
Observers for the day, Mr. Simmonds and Mr. Cris- 
wick, from the beginning of Swing 27 to the beginning 
of Swing 29: for the night, Mr. Ellis and Mr. Dunkin, 
from the end of Swing 29 to the beginning of Swing 32. 
October 10. — Observers for the day, Mr. Rumker and Mr. Pogson, from the 
end of Swing 32 to the beginning of Swing 35 : for the 
night, Mr. Criswick and Mr. Simmonds, from the end of 
Swing 35 to the beginning of Swing 38. 
October 11. — Observers for the day, Mr. Dunkin and Mr. Ellis, from the 
end of Swing 38 to the beginning of Swing 41 : for the 
night, Mr. Rumker and Mr. Pogson, from the end of 
Swing 41 to the beginning of Swing 44. 
October 12. — Observers for the day, Mr. Simmonds and Mr. Criswick, from 
the end of Swing 44 to the beginning of Swing 47 : for 
