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OBSERVATIONS. 

 Micrometer-Observations of Mars at the Cape of Good Hope Continued. 



These reductions rarely afford precisely the same figures as are given in the Memoirs and 

 Monthly Notices of the Koyal Astronomical Society, although only few cases occur in which the 

 discordance reached an amount capable of sensibly affecting the results. This seems best expli- 

 cable upon the assumption that some little excess of delicacy was used at the Cape in points 

 where the consequent accuracy was not thought to warrant fuller minuteness in publication, inas- 

 much as the effect would not be appreciable. In such instances, the figures published by Mr. 

 Maclear have been employed ; and the only deviations from the values given by that zealous and 

 accomplished astronomer are for those cases in which the discordance is clearly due to some 

 oversight in the reduction. This remark applies especially to the Cape sidereal times of 

 observation, which appear to be means between the corrected indications of the clock and those 

 of the hour-circle, and in which the want of entire accordance seems owing merely to some 

 slight difference in the assumed correction of the ephemeris in right-ascension. 



