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AuT. XVI. — The Clock's daily Rate and Error at one time 

 of the Dai/ being known, a Table to find its corresponding 

 Error throughout the day. By James South, Esq. 

 F.R.S., &c. 



To the person attached to the pursuit of practical astronomy, 

 the employment of observing is by no means an ungrateful 

 one ; but it too often happens that observations, when made, 

 require some reductions or corrections before they can be 

 converted to any useful purpose ; a circumstance which has 

 a considerable share in causing the science to be pursued with 

 less advantage by private individuals, than it otherwise would 

 be. Indeed, in this respect, astronomy seems to labour under 

 greater inconveniences than any other department of natural 

 knowledge, unless it be that of chemistry, in which perhaps 

 the amusement of making experiments is sometimes not a little 

 marred by the consciousness that the washing of apparatus, (§-c., 

 must be the inevitable consequence. 



Unable altogether to remove the drudgery of reducing obser- 

 vations, it behoves us, where we can, to lessen it; and, for this 

 purpose, I beg to offer the accompanying tables shewing the 

 error of the clock for any part of the day, its rate and error at 

 one time of it being known ; nor can I allow this opportunity 

 to escape me, without earnestly recommending the amateur 

 observer, to ascertain the precise state of his clock every night, 

 previous to his quitting his observatory. He will find that a 

 constant and uniform attention to the clock, will insensibly 

 entail upon him, habits of accuracy in his other observations ; 

 nor do I know any one thing which distinguishes the accurate, 

 from the slovenly astronomer so much, as the manner in which 

 the performance of the transit-clock, is watched and registered. 



%* The calculations upon which this table is founded, were 

 extended to five places of decimals, so that the third place 

 here given may be considered correct ; and, for the conve- 

 nience of the travelling or nautical astronomer, a table for 

 reducing sidereal to mean solar lime is subjoined, for wiiicli I 

 stand indebted to the industry of the lute Rev. Mr. Wolhiblon. 



