148 Colonel Sabine on the Determination of 



ject. My object, in the present memoir, is to give a rough outline 

 of my observations and theories ; and though I have greatly exceeded 

 my proposed limits, yet I fear that many points will have been far 

 from clearly understood ; for to explain them all thoroughly would 

 require much detail and numerous illustrations. 



Colonel Sabine on the Determination of the Figure and 

 Dimensions of the Globe. 



The determination of the figure and dimensions of the globe 

 which we inhabit may justly be regarded as possessing a very 

 high degree of scientific interest and value ; and the measure- 

 ments necessary for a correct knowledge thereof have long 

 been looked upon as proper subjects for public undertakings, 

 and as highly honourable to the nations which have taken 

 part in them. Inquiries in which I was formerly engaged, 

 led me fully to concur with a remark of Laplace, to the effect 

 that it is extremely probable that the first attempts were 

 made at a period much anterior to those of which history has 

 preserved the record ; the relation which many measures of 

 the most remote antiquity have to each other and to the ter- 

 restrial circumference strengthens this conjecture, and seems 

 to indicate, not only that the earth's circumference was known 

 with a great degree of accuracy at an extremely ancient period, 

 but that it has served as the base of a complete system of 

 measures, the vestiges of which have been found in Egypt 

 and Asia. In modern times the merit of resuming these in- 

 vestigations belongs to the French nation, by whom the arc of 

 the meridian between Formentera and Dunkirk was measured 

 towards the close of the last century. The Trigonometrical 

 Survey of Great Britain, commenced in 1783, for the specific 

 object of connecting the Observatories of Greenwich and 

 Paris, was speedily expanded by the able men to whom its 

 direction was then confided, into an undertaking of far greater 

 scientific as well as topographical importance, having for its 

 objects, on the one hand the formation of correct maps of 

 Great Britain, and on the other the measurement of an arc of 

 the meridian, having the extreme northern and southern 

 points of the Island for its terminations. A portion of this 



