Tuomson.—Colonial Standard Survey. 105 
cal test in the theory of terrestial gravity.* Abnormal states of surface 
curvature have also been detected, and a consequent aberration from the 
true zenith. With these investigations extremely delicate levelling opera- 
tions are carried on by which minute rise and falls in the elevation of land 
are made apparent—the laws of delta depositions, are also effectively 
elucidated. Again, tidal observations have careful and continuous attention, 
whereby not only the general laws that govern these undulations on the 
surface of the ocean are explained but all local phenomena that are 
connected therewith. Then also magnetic declination shares a large 
degree of attention in its hourly, diurnal, and annual motions. With decli- 
nation is also observed the dip of the needle and magnetic intensity in 
different localities and latitudes. Meteorological observations are made at 
different elevations, ete. These minute subtle analyses of physical questions 
(of which the above is the merest abstract) are modern adjuncts to pure 
geodetic or globeform surveys, of which the basis is primary triangulation. 
To propose to undertake the above system of survey, with its great pro- 
longation of time, in this distant part of the world as a basis of settlement 
operations, no doubt carries a certain degree of éclát, but when practical 
considerations are fairly stated as I have endeavored to do, unsurmount- 
able difficulties will be seen to stand in the way. I take it for granted then 
that it will be admitted that such slow and elaborate operations had better 
be deferred till society has grown apace, when great or primary triangula- 
tion may be undertaken, not in a perfunctory manner, which would be its 
necessary character at this present time, but completely and with credit to 
the promoters. 
Hence I would advise that in the New Zealand General Survey staff only 
two or three officers devote themselves to purely scientific observations, such 
as are absolutely necessary for ruling that standard work which connects 
the actual with the geographical. Thus the whole force of the department, 
with the above exception, can be given to the immediate settlement of the 
inflowing people, securing, by the practical system we adopt, their boundaries 
and titles. 
For the above reasons, and at this present period, I do not recommend 
the commencement of primary or great triangulation. What, then, is to be 
done? I reiterate that triangulation is necessary for checking section or 
settlement survey. For this purpose minor or tertiary triangulation cannot 
be dispensed with, as it alone affords points at sufficiently close distances. 
Hence the next question arises: Does it suffice of itself as a connecting link 
between the geographical and actual operations ? The answer is, No. 
* « Philosophical Tranfhetions," London, 1871, and Report Indian Surveys, 1871-72, 
p. 20. 
N 
