APPENDIX III. 
REPORT on the Chronometers supplied to, and the Meridian Distances 
obtained by, H.M.S. Challenger, between the 1st December 1872 and 
the 12th June 1876, by Staff-Commander T. H. Tizard, R.N. 
The sixteen chronometers supplied to the Challenger at Sheerness were twelve box 
and four pocket watches, and in addition a deck watch for ordinary use on board. 
The chronometer room was on the port side of the lower deck just abaft the main- 
mast. In it a platform was constructed on which a wooden tray with twelve partitions 
rested, and the box chronometers were packed in this tray with horse hair (at Sheerness), 
and remained there undisturbed until they were finally returned on the ship’s arrival in 
England in 1876. The platform consisted of three wooden stools of elm, 4 inches in 
thickness, with legs 4 inches in height and width, constructed in such a manner that 
when these stools were placed one upon the other, the legs of the upper stool rested on the 
middle stool immediately over its legs, which again were over the legs of the lower stool, 
so that copper bolts could be driven through the stools and their legs into one of the main 
beams, and thus securely fasten the platform. The wooden tray was secured to the top 
of the upper stool with brass screws, care being taken to keep all iron away from the 
chronometers. Around the platform a wooden screen was constructed, which reached 
just above the top of the tray, and on the top of this wooden screen was a glazed lid on 
hinges, so that the chronometers might be seen for purposes of comparison at any time, but 
neither they nor the platform on which they rested could be touched without lifting this 
lid, which was only done once a day for the purpose of winding. The wooden screen 
which protected the platform and trays was secured to the deck, and kept perfectly free 
from any of the bulkheads, so that its movement, like that of the platform, depended 
only on the working of the beam on which it rested, and not on the working of the bulk- 
heads, which were secured to beams at top and bottom. Before being packed in the tray 
the lids of the boxes which contained the chronometers were unscrewed from the hinges, 
the screws wrapped in paper and put in their respective boxes, and the lids put on a shelf 
overhead in the chronometer room. 
