Jan. 25.] THE NEW ZEALAND GAZETTE. 225

the disposition of natural features and their names, also roads, tracks, ridges, rocks, streams, forests, pas, remarkable objects, natural and artificial, &c., and these must be shown on a topographical map. For altitudes, vertical angles are to be observed to prominent objects, such as peaks, passes, valleys, and confluence of streams. A surveyor with a good eye can make a serviceable sketch-map from his trigonometrical stations, and by theodolite alone, by taking the bearings, cross-bearings, and tangents, with estimated distances of objects; but, if the country be intricate, bearings from intervening positions can be taken where necessary. Prismatic compass and aneroid may be used when the theodolite cannot be had recourse to; in forest country this is especially necessary, as is also the determination of heights of saddles and valleys, river-beds, lakes, swamps, &c.

13. The topographical map is to show the trigonometrical stations, lettered or numbered, trigonometrical heights in feet (in red),—barometrical heights also in red, and marked “Bar.,”—streams (in blue), hills shaded (in Indian ink); the Native or local names of places, streams, hills, &c.; roads in use (in firm burnt-sienna lines), tracks (dotted sienna), bush (green), suggested main lines of future roads (in firm red line), and any other features, natural or artificial, which can be shown. Shade the boundary of the district in colour. Scale, 40 chains to an inch.

RURAL BLOCK AND SECTION SURVEYS.

14. The surveyor must provide himself with a 5in. theodolite, 5-chain tested steel band, Abney level, aneroid, prismatic compass, protractor, mathematical drawing instruments, scales, planimeter, and branding-irons, &c.

15. No magnetic bearings are admissible, unless under very special circumstances in minor detail work, and this very sparingly and with permission. Flat or undulating country should be laid off in rectangular sections, but in rugged or hilly country the ridges and valleys must modify their form. It is desirable to have all the boundaries on the meridian and perpendicular; but when the general features of the country run obliquely to these, especially in rough districts, the boundaries must be arranged accordingly, so as to form lines which can be easily fenced. The less diversity of bearings the better for the avoidance of errors and multiplication of office-work. When necessary, road-lines may cross sections diagonally, but this is to be avoided, and when done, the areas of sections are to be shown in gross and net also. In forest, the boundaries of the block and section-lines for at least 3 chains from the frontage-pegs are to be cut 4ft. wide, the scrub to be cut close to the ground. All trees 2ft. through and under to be cut down, the large ones at 2½ft. from the ground, the small ones 6in. from the ground. The lines to be cut and cleared 7ft. above the ground. In open country the lines must be pared 2ft. wide. Where boundaries cross ridges only such cutting and paring are to be done as will insure the direction being seen from point to point. The back lines of sections in rough country should follow the ridges, to allow of fencing; and this will apply also to section-lines where the sections are large. In ranging long sectional lines crossing ridges, lock-spits are to be cut so as to enable fencers to keep the right line. If the boundaries of the area to be sectionized exceed 3½ miles it will be necessary to divide it into two or more survey blocks, which separate blocks can be reduced into one plan for exhibition to the public. Names should be given to each road surveyed, the Native names to be retained where ascertainable. In cases where roads abut on to or must cross railway-lines, the Surveyor must communicate with the Resident Engineer or District Manager of Railways on the subject, with the view of determining suitable crossings.

16. In traversing, the surveyor is to proceed to the nearest trigonometrical station and base his work on the true meridian of the district by the recorded bearing to an adjacent trigonometrical station. A close should be made with another trigonometrical station, or on to some known point, to test the accuracy of the work. Angles of elevation and depression are to be observed to reduce inclined measurements to the horizontal value. After being located and graded, the road-lines should be traversed, and the surveyor, when at a trigonometrical station, should take careful readings to as many of the traverse or subsidiary points as possible, to check his position as he proceeds. Where possible to do so, all traverses should be pegged before the bearings are observed. All bearings should be repeated to avoid error, and, where practicable, the bearing is to be thrown forward as far as possible to avoid accumulation of instrumental errors. The boundaries of sections should next be run, and, if necessary, be measured. Offsets to irregular boundaries, rivers, or streams must not exceed 4 chains in length, and must be taken at intervals in the traverse not greater than 3 chains, but they must be taken at closer distances if necessary, to correctly define the irregularities to be mapped.

17. All traverses are to be reduced on the meridian and perpendicular of a trigonometrical station, and this should be done daily, so that no actual measurements get in advance of this mode of check on the operations. Special instructions will be issued as to what trigonometrical station the work is to be co-ordinated with, in case it is impossible to use the circuit origin. As a rule, the origin of the circuit is most convenient, and affords at once a ready check by comparison with adjacent work. In rural and suburban surveys the position of all actually chained lines (excepting to range pegs), all corners of blocks and of isolated sections, whether chained or not, and the intersections with the traverses of all boundary-lines of sections, are to be calculated and tabulated. Should two traverses—say, of a road and of a river—run nearly parallel and not more than about 10 chains distant, it will not be necessary to calculate both, nor, when surveys already co-ordinated are used in the survey in hand, will it be necessary (unless specially called for) to recalculate such previous traverses so long as the closure is shown on the traverse-sheets of the new survey. The calculated positions on meridian and perpendicular are to be entered in the form marked A in the Schedule hereto, and are to be forwarded with the map.

18. Unless where otherwise specially ordered, main and cross road-lines are to be pegged generally to a breadth of 1 chain, occupation roads to ½ chain, main roads 3 to 4 miles apart, by-roads or cross-roads ¾ to 1½ miles apart, and all necessary through roads to give access to back or adjoining country 1 chain wide. In very broken country it is advisable to increase the width of roads. In level country the opposite angles should be pegged by setting off half the included angle and calculated distance; but in hilly and mountainous districts, where the land is of little value, the roads tortuous, and the traverses short and intricate, pegs at angles may be dispensed with and the roads shown by straight or curved lines adjacent to conveniently-situated tra-