154 APPENDIX. 
serve to render them useful for zero points, to which the 
secondary stations may be referred either by dead reckoning 
of time and distance, or by such less elaborate observation 
as can be obtained at the secondary stations themselves. 
Of course, however, should circumstances permit, the more’ 
important in other respects the point which can be made a 
primary observing station the better; and the Committee 
would expressly notice Griqua Town, Litakou, Curechane, 
and Meletta, as points of which the geographical position 
should be determined with care by observations on the spot, 
and the observations then made be transmitted home along 
with the latest communication with the Colony. Since, 
however, the circumstances which may render stations ob- 
jectionable, as primary points, are mostly of a moral, or 
political nature, it is expected no great difficulty will occur 
in fixing them at positions of especial geographical interest, 
—as at the confluence of rivers, at the extreme borders, or 
on the culminating points of mounting ranges, on remark- 
able rocks, &c.,—or at least of determinating their bearings 
and relative situations with respect to such prominent fea- 
tures with some degree of exactness. A combination of 
circumstances of this kind of local interest will of course 
have its due weight in determining (ceteris paribus) the 
halt of the expedition. 
At primary stations the Committee recommend the 
assiduous application of every instrumental means for the 
determination of the three elements of latitude, longitude, 
and elevation above the level of the sea, and especially at 
such stations, as many series of lunar distances as possible 
should be procured in addition to the usual sights for time; 
(or observations of the altitudes of the heavenly bodies near 
the prime vertical) which, together with meridian observa- 
tions for the latitude, they would recommend to be practised 
