There's a difference between a chronometer watch and a "bull's eye."

A chronometer watch, which was committed to the care of the writer by Hayes, bore this inscription:-

I don't like to touch it.' It was Captain Brierly's gold chronometer watch carefully hung under the rail by its chain.

With only one chronometer watch, one has to rely entirely on dead reckoning for longitude, the rate of a single watch being very variable.

There were five watches among us, of which three were chronometer watches.

We had, in addition, six chronometer watches, which we wore continually, and which were compared throughout the whole winter.