ORIGIN AND PROGRESS OF GEODETIC SURVEY IN SOUTH AFRICA. 245 
and it is only waste of time, therefore, to compute corrections to the 
chain, which will certainly have to be replaced by others at a later date. 
The geodetic amplitude could be greatly strengthened by a direct 
connection southwards, across the Orange River, between the sides 
Spitzkopje-Karasberge-Sonnabende Hugel with the sides Naib-Agenys 
or Agenys-Eitjes of Alston’s triangles. We may confidently rely on the 
scientific spirit of Germany to measure at least another base and increase 
the number of astronomical stations on this arc. 
Arc near the Meridian of 26° BE. Longitude. 
This are is at present incomplete, because the triangles connecting 
Kimberley and Ottoshoop are not yet measured. ‘The geodetic latitudes 
will depend on two parallel chains of triangulation which unite at the 
northern part of the arc, and cover about 4° in longitude. The astro- 
nomical observations at some of the stations have not yet been reduced, 
and further astronomical stations are required at the northern end of 
the are. 
The results, however, are interesting as they stand. 
Astron, minus Astron. minus 
re | Tiong. | aa Geod. Lat. Geod. Azimuth 
| ° , ° Ud ” ” 
| Cape St. Francis | 2 46 3t 10 + 084 ooo 
Buffelsfontein' . Fa — — ~ 0°00 0.00 
Port Elizabeth. 4 | 25 37 | 33 58 — 737 =~ 0:90 
Coega Kop Foereah 33 46 — 790 _— 
Zuurberg . » {| 25 84 | 33 14 + 10°96 — 
Drivers Hill. » | 26 42 33 (17 + 1:87 — 
Berlin : ; a ee a 32 53 + 6°80 + 0°53 
Grassberg . ot eftetle 24 29 a2po +1074 | _— 
Lubisi - : -| 27 30 3L 47 | Not yet reduced 
Tafelberg . - - | 26 10 31 38 + 0°32 — 
Washbank Peak ik 27 (30 31 12 | Not yet reduced 
Hanover . : ‘ 24° 26 Se A — OOoL —- 
Helvelyn . : see 27) wt 30 40 | Not yet reduced 
Aasvogel Kop . si |R£2 5 30 14 | Not yet reduced 
De Put. - 23 «55 30 14 | — 058 — 
S. End Wepener Base | 27 1 29 50 | Not yet reduced 
N. End Wepener Base 26 59 29 37 | Not yet reduced | Not yet reduced 
Kimberley : . | 24 43 28 38 — 157 +1:07 
N. End Ottoshoop 
Base. - - | 25 53 25 33 — 445 + 2°06 
! Buffelsfontein is the origin of the latitudes and azimuths of the system. 
The accuracy of the arc when the connection between Kimberley and Ottoshoop 
has been completed will be very great, as practically five first-class base lines enter 
into the control of its geodetic amplitude, as well as an excellent gridiron system. 
The large local deviations of gravity (—74"' near Port Elizabethand + 103"’ at Zuurberg 
and Grassberg) tend somewhat to diminish the value of the arc as a measure of the 
earth’s mean curvature, 
Great Are along the 80th Meridtan north of the Limpopo. 
From the Limpopo northwards to the following triangles a gap exists, 
not yet filled, and the station Salisbury is taken as the new origin both 
for latitude and azimuth. 
