ORIGIN AND PROGRESS OF GEODETIC SURVEY IN SOUTH AFRICA. 229 
in two volumes, by order of the Lords Commissioners of the Admiralty, 
in 1866. Maclear’s are has an astronomical amplitude of 4° 37’ in 
latitude, and proves, within moderately narrow limits, that the form of 
the earth in the southern hemisphere is similar to that in the northern 
hemisphere. 
The astronomical amplitude of La Caille’s arc proved to be very 
nearly correct, but a large local disturbance of the direction of gravity at 
La Caille’s northern station, amounting to more than 8” of arc, accounted 
for the greater part of the apparent error of his work. 
Nothing in the way of further systematic accurate triangulation was 
done in South Africa till 1859, when a triangulation of the southern 
coast of Cape Colony and British Kaffraria was set on foot, the Colonial 
Government being urged thereto by the demands of the Admiralty for the 
accurate determination of points on the coast-line in connection with the 
hydrographic survey which they were about to undertake, in order to 
correct the then very inaccurate and defective state of the charts of the 
coast. It was evident also that such a survey would furnish means of 
better connecting the detached property surveys through that part of the 
Colony. The work was entrusted to Captain Bailey, R.E., aided by one 
sergeant and thirteen rank-and-file of the Royal Engineers, five of whom 
were selected from the Ordnance Survey of England. The cost of the 
work was borne by the Colony ; it was begun in 1859 and concluded in 
1862. The party embarked at Algoa Bay in the ‘ Waldensian,’ en route 
for England. The vessel struck upon the rocks off Struys Point and 
became a total wreck. On board were the instruments, drawings, 
original observation books, with full abstracts, calculation books of every 
kind, all complete in every respect. They were all lost,and have never been 
recovered. Fortunately, copies of ‘abstracts of angles’ had been supplied 
to the Admiralty Surveyor engaged on the Coast Survey, other abstracts 
of angles with a diagram to the Surveyor-General in Cape Town, and from 
these and sundry copies sent to the Government of British Kaffraria and 
to private individuals an account of the work was compiled by Captain 
Bailey, and printed in a report presented to the Cape Parliament in 
1863. 
Soon after appointment to my present position at the Cape in 1879 
I began to study the general question of the geodetic survey of South 
Africa. The traditions of my office appeared not only to justify, but to 
demand, that some portion of my time and attention should be devoted to 
this work, Sir Bartle Frere was then Governor of the Cape Colony and 
High Commissioner for South Africa. 
From his experience of administration in India His Excellency 
thoroughly realised the advantages and the necessity for accurate survey, 
and the true economy of basing all future surveys upon a principal tri- 
angulation of such accuracy that its results might be considered definitive 
for all future time, and he gave my recommendations his strongest sup- 
port. 
These recommendations embraced a plan for a gridiron system of 
chains of principal triangulation extending over Cape Colony, the Orange 
Free State, Natal, and the Transvaal. 
The political and financial situation in the Cape Colony at the time 
rendered it difficult for Ministers to take action during the session of 
1880. But soon afterwards I had, through Sir Bartle Frere’s kindness, 
the opportunity of meeting Sir George Pomeroy Colley, when His Excellency 
