of Van Dlemeris Land. ' 87 



The Bases are situated nearly 100 miles asunder. The 

 computed length of the Longford Base, taken from the 

 measured length of that at Ralph's Bay, and carried up 

 through thirteen triangles, compared with its measured 

 length, gives the following results, viz. : — 



Mean of two measurements ..35,746*2 feet 



Reduction to level of sea "5 



Reduced measured length 25,745'7 



Computed length 25,746-0 



Difference feet '3 or about Sc- 



inches. The instruments are decidedly good of their kind, 

 but not of course possessing the perfection of construction 

 or minuteness of division of those used in the great surveys 

 of Europe, India, and America. The observations have been 

 entirely in the hands of one individual, Mr. J. Sprent, 

 whose scientific knowledge, together with untiring perse- 

 verance and patient endurance, has enabled him, single- 

 handed, to effect what would in other countries have been 

 shared by many equally qualified for the work. But the 

 result is such as he will I am sure, from the interest he takes 

 in this work of science, feel no small recompense for his 

 efforts. 



The actual distance from hill to hill, extending for nearly 

 fifty miles in some of the triangles, and the total distance from 

 Base to Base being determined to a very minute degree of 

 accuracy, a foundation of the framework of the whole map 

 of the island is established, and the future operations will 

 be based upon it with security and confidence. 



" (Signed) " H. C. Cotton." 



Since the date of the above Report I have made further 

 computations for the verification of the work, comparing 



