I should, perhaps, mention that Mackenzie omitted to wind his
watch, and so could not carry Greenwich time from his last observing
place. This fact would not affect the necessity for a final observation
as it would have been impossible, in view of the conditions under which
MacKenzie was travelling, to carry a satisfactory determination so.
far with a single timepiece. The geographical result of the observation
was most valuable as Mackenzie was able to say with certainty that
he had reached the shores charted by Vancouver and not one of the
inland seas which had appeared on the map for centuries, and which
Meares had reported only three or four years before.

My main object in discussing the longitude in detail is to shew
that the apparent inaccuracy of the result is due to the circumstances
and to the nature of the observation, and that it casts no reflection
on Mackenzie’s reliability or steadiness as an observer.

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