ADVANTAGES POSSESSED BY COL. LAMBTON. 317 



triangles was determined, by eminent French mathemati- 

 cians; between Paris and Calais, Blancnez and Montlam- 

 bert, points near the French coast opposite to Dover, and 

 the British and French triangles were then connected by 

 observations made across the Channel, by means of lights 

 exhibited at the stations. At that period the English artists 

 excelled all others in the world in the construction of ex- 

 quisitely-divided astronomical instruments. Probably the 

 French mathematicians employed on this occasion were 

 superior to the English in the refined theories of moderii 

 analysis. However this might be, the series of geodetical 

 operations then begun soon called into action the exertions 

 of artists and mathematicians to the great benefit of astro- 

 nomical and geographical science. , . , , , , . , 



Colonel Lambton, then, in beginning his labours, had tire 

 advantacre of excellent instruments ; a theory almost per- 

 fect in the writings of Delambre and Legendre ; the pre- 

 vious example of the British trigonometrical survey along 

 the southern and eastern coasts of England, by Colonel 

 Williams, Captain Mudge, and Mr. Dalby, the account ot 

 which, to one about to commence a like labour, was, as he 

 says, a treasure. There must have been partial surveys 

 of portions of our Indian territories before this time ; but 

 these were all conducted on principles much inferior m ac- 

 curacy to those employed by Colonel Lambton, and with 

 less perfect instruments. 



The survey of a kingdom, or of such an extent of country 

 as that undertaken by Colonel Lambton, besides requiring a 

 detrree of intelli<Tence and resources much beyond what are 

 necessary in the survey of a district of no great extent, 

 wanted turther for its complete execution two most important 

 elements,— one of these is the magnitude, and the other the 

 fiaure of the earth. The dilficulty of resolving these prob- 

 lems in geography was, therefore, to be surmounted ; and 

 for their solution, besides purely mathematical know'led^e, 

 various applications of the doctrines of astronomy and other 

 branches of physical science were essentially necessary. 



The general" object to be attained in the survey of a coun- 

 try is to determine the precise position of every remarkable 

 point, and the exact direction of straight lines joining them, 

 as well in respect of each other as in respect to the merid- 

 ians which they intersect. To effect this four serarate pro- 

 Dd2 



