I've been writing both in a Bulletin Article and on this board about the Negus brothers and their chronometers. I've also featured Negus #1273 as it has a very impressive history of service in the United States Navy and I also happen to be fortunate enough to own it. It is an instrument that was no doubt accurate enough to be assigned to various Naval ships of war but also to important scientific and geographic expeditions. I was curious as to how accurate these chronometers were back in the day and what results the Naval Observatory achieved in testing them. Here is a U.S.N.O. report from 1912 which records testing results of 1273 when it had been in service nearly 50 years! These are mean daily rates.I think most impressive. I don't know if some of the other results can been read from the document but other chronometers achieved impressive results also and these results are a credit to their respective makers and the Naval Observatory in their efforts to keep these remarkable instruments functioning to the standards they achieved.
January 9-16 +1.46 (seconds)
January 18-25 +0.33
Jan.27-Feb.3 -0.64
February 5-12 -0.06
January 9-16 +1.46 (seconds)
January 18-25 +0.33
Jan.27-Feb.3 -0.64
February 5-12 -0.06


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