test in the theory of terrestial gravity.* “Philosophical Transactions,” London, 1871, and Report Indian Surveys, 1871–72, p. 20. Abnormal states of surface curvature have also been detected, and a consequent aberration from the true zenith. With these investigations extremely delicate levelling operations are carriėd 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 declination is also observed the dip of the needle and magnetic intensity in different localities and latitudes. Meteorological observations are made at different elevations, etc. 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 prolongation of time, in this distant part of the world as a basis of settlement operations, no doubt carries a certain degree of éclât, but when practical considerations are fairly stated as I have endeavored to do, unsurmountable 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 triangulation 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.