TRIGONOMETRICAL SURVEY OF INDIA. 



211 



between actual measurement and computation; but a length of 1'081 in 

 5260.03 amounts to 13 inches in a mile, or 104 inches in 8 miles, and 

 nearly 38 fathoms in a section of 3 degrees. In the month of April, 1751, 

 MM. Maire and Boscovich, under the auspices and at the charge of 

 Pope Benedict XIV, commenced the measurement of a base line from 

 the tomb of Cecilia Metella to within 3 miles of Alba. The operation 

 was executed with wooden rods set off from the Roman palm, and was 

 found to be 7901.14 passi Romani, equal to 7.312 English miles : the base 

 of verification for this was measured at Rimini, and found to be 8034.67 

 passi, equal to 7.436 miles, whereas the latter deduced from the former in 

 the table of triangles (Liv. II. Art. 20,) is only 8033-4, differing 1.27 

 passo, or 10 inches in a mile. 



The length of the base of Perpignan is 6006.25 toises, it was com- 

 menced by Mechain and finished by Delambre, in the month of Germinal, 

 year 6 of the Republic, with the platina bars. It was connected with that 

 ofMELUN, which was executed by DelaiMbre, and is 6075,9 toises, the 

 former deduced from the latter is 6006 09, exhibiting a difference of 0'16of 

 a toise, which is about 0.17 of an inch in a mile. The latter was completed 

 in thirty-eight days : the expressions of the author are — " en travaillant de- 

 puis neuf heures du matin jusqu'au coucher du soleil nous n' avons jamais 

 pus parvenir i\ mesurer plusde 360 metres* en un jour, c'est;\ dire, i\ placer 

 plus de quatre vingt dix regies au bout Tune de l autre." The base of 

 Perpignan occupied in all 48 days, and was terminated on the 1st supple- 

 mental day of the year 6. The author says in regard to this — "on volt 

 done {]ue dans les circonstances les plus favoral)lcs ou no pent gui re se 

 flatter avcc tons les soins ct Ic scnipuh^ (|iic nous \ apportions do nu'surcr 

 unc base dc j 12()()() mrtrcs cn inoins dc ci iu|uaii((' jours. ' 



* 1181-1 237 Enfj;li*li feet. 



f 39370.79 i'cct, or 7^ miles nearly, wliicli is at tlic rate of 797 ur 800 feet per day. 



