ORIGIN AND PROGRESS OF GEODETIC SURVEY IN SOUTH AFRICA. 231 
On the immense importance of the proposed work as a geodetic opera- 
tion it is unnecessary to dwell ; the measurement of an are of meridian 
65° in amplitude would be a gain to geodesy so vastly important as alone 
to justify its inception. 
But this is not all. By an additional chain of triangles from Egypt 
along the coast of the Levant and through the islands of Greece the 
African are might be connected with the Roumanian and Russian are, 
so as to form a continuous chain of 105 degrees in amplitude, extending 
from Cape Agulhas to the North Cape—the longest are of meridian 
measurable in the world. 
This object I have ever since constantly kept in view, and I have lost 
no opportunity of forwarding it. 
Meanwhile, during the later stages of the field-work in Cape Colony 
and Natal, questions connected with the delimitation of the boundary 
between British and German territory in 8.W. Africa had sprung up. 
That boundary is the subject of an agreement between the Governments 
concerned which was signed at Berlin in July 1890. It is defined to the 
south by a line commencing at the mouth of the Orange River, and 
ascending the north bank of that river to the point of its intersection by 
the 20th degree of east longitude, and, running then northwards along 
the meridian to the point of its intersection by the parallel of 20° south 
latitude, then eastward along that parallel to the point of its intersection 
by the 21st degree of east longitude, and thence northwards to the point 
of its intersection by the parallel of 18° south latitude. 
Mr. Bosman had executed a chain of triangles from the neighbourhood 
of Vryburg westwards to the 20th meridian. This chain rested on a base 
. line measured by Major Laffan, of which he also determined the orienta- 
tion and the latitude aud longitude of one of its extremities by astronomical 
observations, exchanging telegraphic signals for the latter purpose with 
the Cape Observatory. It should be mentioned to Mr. Bosman’s credit 
that, although his work was paid for by the Bechuanaland Government at 
the tariff rates of secondary survey, Mr. Bosman made it his ambition to 
render the work fit for incorporation as an integral part of the geodetic 
survey. He procured a 10-inch theodolite at his private cost, and came 
to the Observatory for practical astronomical training, and he made a 
rigorous least square solution of the complex figures of which some parts 
of the chain were composed. 
The work of Bosman and Laffan practically settled the position of the 
20th meridian in the neighbourhood of the Orange River, and as far 
northwards as Reitfontein; but administrative difficulties soon arose 
further northwards, where there appeared to be an uncertainty of 18 or 
20 miles as to the true position of the 20th meridian. 
A temporary settlement of outstanding difficulties was made by Ger- 
many agreeing to withdraw from certain points near the boundary in 
dispute, and Great Britain undertaking that Bosman’s triangulation 
should be extended northwards to the 22nd degree of south latitude. 
_ Matters were in this state of friendly suspense when I visited England 
in 1896, and was consulted by the Colonial Office as to the means necessary 
to carry this promise into effect. 
I then pointed out that from Reitfontein (the northern point of 
Mr. Bosman’s survey) the 20th meridian crossed the Kalihari Desert, a 
country so flat and waterless that it would be difficult, if not impossible, 
to triangulate it. If, therefore, the triangulation had to be extended 
