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LXX1X. On some Extraordinary Inconsistencies in the Green- 

 wich Observations for 1821. By S. Lee, Esq. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 



TN my letter of the 24th November last, I pointed out some 

 extraordinary inconsistencies in the Greenwich observa- 

 tions for 1821. I now proceed to notice some others of a 

 different description, and which for the reasons already given, 

 I have arranged in three separate additional classes. 



Class IV. exhibits a comparative view of the intervals of time 

 between the meridian passages of certain stars, as observed 

 on the same night, with the transit instrument and the mural 

 circle. 



Class V. contains the north polar distances of y Draconis, 

 and some other remarkable stars, taken out of the observa- 

 tions with the mural circle, from readings with two and with 

 six microscopes. 



Class VI. gives the intervals of time between the passage of 

 some of the principal fixed stars, by the wires of the transit 

 instrument, as observed on different nights. 



With respect to the three first classes, little more can be 

 said than that they prove extreme carelessness in the observer, 

 the transcriber, or the computer ; for, as I have already stated, 

 they are not the faults of the printer. 



The fourth class show that proper care has not been taken 

 to bring the plane of the mural circle truly into the plane of 

 the meridian. It may be alleged, that a small deviation 

 therefrom does not, in most cases, occasion any considerable 

 error in the north polar distances : but it must also be ad- 

 mitted, that such want of adjustment, however insignificant 

 its effect, ought not to be allowed to remain in one of the prin- 

 cipal instruments of the Royal Observatory at Greenwich. 



It is very remarkable that so few transits should have been 

 taken with the Circle, and that the stars observed should be so 

 ill adapted to the purpose of ascertaining the correctness of 

 its position. Indeed, it is hardly possible to imagine a more 

 injudicious selection. 



The observations which form the fifth class were extracted 

 for the purpose of ascertaining the stability of the Circle. 



A very slight comparison of these extracts with one an- 

 other, will convince any one (supposing the observations to 

 have been carefully made and accurately recorded) tli at the 

 instrument must be extremely unsteady. 



Such extravagant variations of north polar distance from 

 3 L 2 one 



