'■--So 



' .wDiVju. AN EXPLANATION 



OF THE METHOD OF ADJUSTMENT 



OF THE 

 OF 



HADLEY'S QUADRANT, 



BY TWO NEAR OBJECTS : 



^I'P Ui.. 

 ALSO A DESCRIPTION 



OF A PROJECTED ADDITION TO THE QUADRANT^.,' / 



50H REFLECTING THAT ADJUSTMENT ACCOKDING TO THE METHOD OF 



MR. BLATR,, 



BY THE REV. JAMES LITTLE. 



■^ca^^id^O^^^ 



,Rcad, January 28th, 1811. 



How desirable as well as difficult it is, to adjust on every 

 occasion the Back Horizon Glass of Hadley's Quadrant with 

 necessary precision, is declared by the many different con- 

 trivances which have been suggested for that purpose ; and 

 this I hope will procure an indulgent approbation of the pre-^ 

 sent, as well as the future, attempts that may be made for 

 that end, till it shall be accomplished in every manner de- 

 sirable. The mode of its adjustment, by two near objects,, 

 has been described by the late Rev. Mr. Ludlam in his trea- 

 tise on the quadrant ; and it may b}' this be accurately per- 

 formed, if executed with due and intelligent attention to the. 

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