Mr Harvey on the Rates of' Chronometers. 



171 



the nearly equal uniformity of temperature also, that prevailed during the 

 experiments, and from the positions of the Chronometers, with respect to 

 the magnetic meridian heing constant, there can be no doubt, as Mr Har- 

 vey remarks, but the different alterations of rate are due to alterations of 

 pressure. As the results relating to the last mentioned Chronometers are 

 very interesting, we subjoin them. 



EXPERIMENTS WITH TWO POCKET CHRONOMETERS. 



One of the most interesting parts of this paper, however, is the inquiry 

 respecting the probable alteration of rate that would be produced in a Chro- 

 nometer, by transporting it to any place elevated considerably above the 

 level of the ocean, as from London to Geneva, or from the shores of the 

 Mediterranean to the lofty plains of La Mancha and the Castiles, or from 

 Vera Cruz, on the shores of the Pacific Ocean, to the Table Land of Mex- 

 ico, where the mean atmospheric pressure is denoted by 23 inches of the 

 barometer, or to the still loftier elevation of Quito, where the density of 

 the air is denoted by only 21 inches of the mercurial column. The fol- 

 lowing table contains a few of the very interesting results obtained by dif- 

 ferent Chronometers. 



