404 ACCOUNT OF SOME TRIGONOMETRICAL OPERATIONS, ETC. [49 



of the base, combined with the corresponding ones at the station at St John's, 

 furnished two determinations of the distance of the Cambridge Observatory, 

 which served to check one another. The meridian line of the transit instru- 

 ment at St John's passes through King's College Chapel, so that by observing 

 the point at which it intersected the base, the azimuths of the sides of 

 the triangles could be immediately found. 



The result thus obtained is, that the transit instrument of the Cam- 

 bridge Observatory is 2313 feet to the north, and 4770 feet to the west 

 of that at St John's College. Hence it follows that the difference of latitude 

 is 22"'8, and the difference of longitude 5"'10; and the latitude of the 

 Cambridge Observatory being 52 12' 5l"'8, and its longitude 23"'54 east of 

 Greenwich, we have finally for the geographical coordinates of the Observatory 

 of St John's College, 



Latitude 52 12' 29"'0 



Longitude 0' 28"'64 E. of Greenwich. 



These operations, of course, furnish incidentally a very exact determi- 

 nation of the orientation of King's College Chapel. The line of the ridge 

 of the roof points 6 20''3 to the north of east. 



