or less partial and imperfect, and therefore not desirable

records.

Division of Labor.

It is next to impossible to lay down absolute and distinct rules for the performance of detail duties. As before stated in Chapter XII. every Surveyor may have his own peculiar method of carrying out his work, and in such matters they will be the best judges of the nature of the work they have to perform and of the best means of completing it, all that we advocate is system in all that is done, and whatever that method may be, after it has been once maturely considered and definitely determined on, it should not be departed from. Let a Surveyor apportion out to each assistant the particular duty for which he is most qualified, and insist on its being followed. As a general rule each assistant is responsible for the division he has had charge of in the Field, and is expected to bring up the whole of the work connected with it, but it frequently happens that from local causes, one party may accomplish more Field work than they can get out of hand prior to the commencement of another season, whilst another party may not be so pressed for time in the recess, such additional aid and assistance therefore as can be spared, should be afforded where it is most needed. Each assistant has generally five Native Surveyors of various degrees of qualifications under him. One may color well, another may print well, and so on. One man may be employed simply in pricking and tracing off, and pencilling in the village plans. These are made over to a second person, to ink in, to a third to be colored, and to a fourth to have station points, letters and lines entered, and lastly on to a fifth to write and print adjoining names; such a party can complete from fifteen to twenty village maps daily.

By this arrangement the Sub-Assistant is enabled to devote himself chiefly to the more important points in finishing the pergunnah maps and areas, and the Superintending Officer in

exercising a general control over the whole work, taking care that it progresses through every step to his satisfaction, methodically, cleanly, and accurately; encouraging and helping in all difficulties, and by putting the finishing touches to the plans render them worthy of his professional reputation.

By the means we have here endeavoured to describe, a Surveyor may have the satisfaction of seeing his office cleared by the termination of the recess, and find himself in a position to take the Field again with renewed vigor, unembarrassed by any arrears.

CHAPTER XXVI.

ON THE METHOD OF DESCRIBING THE GRATICULE
OF MAPS.

FOR the purpose of representing more accurately the globe which we inhabit, geographers have had recourse to spherical balls, on the surface of which are drawn the various divisions of the earth, but the relative divisions of the earth, and the positions of places, cannot be accurately laid down on these spheres, till certain circles have been described on its surface. These circles are divided into great and small, and the manner in which they are formed may be described as follows. Imagine a sphere to be cut in any direction by a plane, the section will be a circle. It would be a great circle if the cutting plane passed through the centre of the sphere, and a small circle, if it (the cutting plane) passed out of that centre.

Of the Axis and Poles.

From the manner in which a great and small circle are generated, it is evident that the former will bisect the sphere, while the latter will make an unequal division of it. The earth turns round once in 24 hours, on an imaginary axis, passing through its centre; the two extremities of this axis, are its poles, the one being called the North and the other the South Pole. This being apprehended, conceive now the terrestrial sphere to be cut by a certain number of planes perpendicular to the rotatory axis, the sections will obviously be parallel to each other; that passing through the centre of the sphere (a great circle) being called the equator, or the equinoctial line, while all the others.

(small circles) are styled the parallels of latitude, or simply parallels.

Again a point being assumed on the terrestrial globe, the cutting plane may be imagined to pass through it, and the axis of rotation, the section (a great circle) will be the meridian of that point, being perpendicular to the equator, and to the parallels, and passing through the North and South Poles.

The latitude and longitude of a place may be defined in the following manner. The meridian to the given place being drawn in the way above described, the section thereof intercepted between the equator and the given point is called the latitude, which will be North or South, according as the meridional section, which is its measure, extends towards the North or South Pole. The longitude is reckoned upon the equator commencing from a point arbitrarily assumed as the origin, and continued as far as its intersection with the meridian of the given place. In English works on geography the meeting of the equator with the meridian of the Greenwich observatory, is taken as the origin of the longitudinal arc which is measured both ways, viz. to the East and West of that meridian.

"By way of illustrating the foregoing definition of latitude and longitude let us suppose that PEP'Q in adjoining diagram represents the earth,

Illustration of La

titude.

divides the earth into two hemispheres; EPQ being the Northern, and EP'Q the Southern hemisphere.

"Let G, I, K, represent the situation of three places, on the surface of the earth, through which, let the great circles PKP', PIP', and PGP' be drawn, intersecting the equator EQ, in n, m, a, respectively.

"These circles are the meridians of the places K, I, G, and as every circle is supposed to be divided into 360° there must be 90° from the equator to each pole. Hence the latitude of the place K is measured by the degrees of the arc intercepted between K and n; and the latitudes of G and I are measured by the degrees of the arc intercepted between G and a, and I and m, respectively. These latitudes will be called North latitudes, because the places lie in the Northern hemisphere.

gitude.

"In like manner, let there be two places W and V in the Southern hemisphere. The latitude of W will be measured by the degrees of the arc intercepted between W and a, and the latitude of V, by the arc intercepted between V and m, and these will be called South latitudes. The distance between I and Vis called the difference of latitude. "The longitude of a place is measured by the degrees of an arc of the equator, intercepted between some Illustration of Lon- particular meridian, and the meridian passing through the place. Thus suppose G to represent the particular meridian and m to represent the place whose longitude is required; the longitude of m is measured by the arc ma of the equator, intercepted between a and the point where the meridian of G meets the equator, and m the point of the equator where it is cut by the meridian of the place m. The particular meridian, from which we begin to reckon the degrees of longitude, is called the prime or first meridian, and it is different in different countries.

"In the foregoing diagram if G represent the observatory of Greenwich, a will be the point from which we begin to