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shape, and position of all you have to deal with. A little time spent in first walking over the ground will save time in the long run. The scale to which the plan is required to be plotted should be also settled at the outset, if possible, as upon this decision would depend the amount of measurements needed to be taken for the offsets.
The importance of being provided with a change of clothing to suit all weathers cannot be overrated. The only real impediment a surveyor has to accept is a thick fog. Good stout boots are essential in field work. The comfort of shooting boots, where much walking about on rough ground has to be done, is only realised by those who have tried them. Two pairs are advisable to wear in turn upon alternate days. The boots are preferably of porpoise hide, well made, of good fit, free from soft lining (which is liable to pucker), broad at the tread and stout in the sole, and fastened by leather laces. Some surveyors wear breeches and gaiters. Knickerbockers, with box-cloth bands fastened with three or four buttons at the side, are better than straps or garters, which tend to prevent a proper circulation of the blood. When leggings are put over thick stockings they keep the calf of the leg too warm, and consequently encourage a feeling of laziness. Trousers are better in all weathers, as socks can be worn to suit the time of year, and leggings over the trousers in wet weather. A light mackintosh should be available. It is a good practice to establish a daily roll-call before starting in the field, enumerating the articles required for the day's work, in order that nothing may be forgotten. As regards men, it is a mistake to work short-handed. Men are needed to carry pegs and act as labourers in addition to those engaged as chainmen. In the country, it will generally be found that the "boots" at the hotel will possibly know of honest, sober men acquainted with the district, and perhaps those who have been out before as chainmen, and who will not therefore need the amount of training required by those who are not accustomed to the work.
RANGING OUT A LINE.
IN making a survey the first thing to be done is to determine the best positions for running the straight lines upon which the survey is to be based, and the next is to range out the base lines before measuring them from one station to the other. Ranging rods, of lengths varying from 5 ft. to 7 ft., are usually made circular in section, and painted in lengths of one link (7'92 in.), 9 in., or 1 ft., white, red, and black alternately. When one colour at a distance cannot be clearly seen against a background, one of the other coloured portions can generally be distinctly observed. White is most suitable for most backgrounds, but for a pale grey aspect, such as is presented by ploughed land, black is preferable, and for a green background, a red colour on the rod is preferred. For use at a considerable distance it is well to attach a flag of red and white bunting of about the size of a pocket handkerchief permanently to the top of certain poles, or in the absence of a more suitable signal a pocket handkerchief may be temporarily employed for the purpose. Some think it useful for long distances to fasten a piece of white canvas by tapes halfway up the rod. The surveyor must agree with his assistant as to the signs he intends to adopt for directing him in the field when setting a pole or ranging rod in a required line; and the pole must not only be fixed in the ground upon this line, but be left vertically in position. The latter precaution can generally be accomplished by eye, but where great accuracy is required the aid of a plumb-bob, as shown in fig. 2, must be introduced, the string from which the plumb-bob is suspended being turned over the first and second fingers of the hand, so that when the string hangs vertically the pole may be set parallel to it. The detail of the plumb-bob in fig. 5
(pages 6, 7) shows the top unscrewed for the purpose of attaching the suspending cord by means of a knot. Whipcord is the best to employ, as it wears better than string. A good form of plumb-bob for carrying in the pocket is shown in fig. 3, with a reversible point which screws up inside the hollow case forming the body-piece of the plumbbob. Sometimes a square distance plate equal in width to the diameter of the cylindrical case is added, which is useful when checking the perpendicularity of walls. There is no fixed distance between the ranging rods. They serve to give direction only, except at the intersection points, when their position is accurately recorded. (See fig. 1, pages 6, 7.)
A straight line may be set out by successively placing poles in the ground in line with one another at convenient distances apart in the order marked 1, 2, 3, 4, 5, in fig. 1 (pages 6, 7), when one station B is fixed, the line being found to pass through A. The surveyor stands at a short distance from A behind the pole looking towards B with both hands free. The accuracy of the operation is promoted by not letting the eye be too near the pole A from whence the observation is made. If the intermediate pole requires to be moved towards his left, he indicates this to his assistant by moving his left hand in that direction. If the intermediate pole requires to be moved towards his right, he directs his assistant with his right hand in a similar manner. The assistant places himself a little off the line, facing a direction at right angles to the line, so that he does not impede the line of sight and can turn his head round to receive further instructions from the surveyor. He must only hold the pole which he is directed to set with one hand and the surveyor in giving him the signals for so doing, should present the palm of the hand he holds up towards his assistant, as the full width of the hand is better to see than the edge. Any other spare poles should be laid down upon the ground, or be carried by another man, or boy, at a short distance from the line, otherwise they may confuse the surveyor in setting the pole required. Should the bottom of the pole be in the correct position, but the pole itself not quite upright, the surveyor may hold the elbow of his right arm with his left hand and move the right hand, palm
SETTING OUT LONG BASE LINES IN OPEN COUNTRY
SHOWING THE METHOD
NOTE IT IS NOT NECESSARY TO MARK THE DISTANCE OF ALL TH
RANCING OUT A
WITHOUT THE US
THE METHOD ADOPTED FOR PLACING THE INTERMEDIATE
IT WILL BE CIDENT THAT THE FARTHER APART THE POINTS D
PLAN SHOWING POSITION
COUT A LINE
ACE OF THOSE USED
RECORDED IN THE FIELD BOOK.
A LINE OVER A HILL
ISE OF A THEODOLITE
NOTE THE FICURES CIVE THE ORDER
=POLES DANDE IN THE LINE C F IS EXPLAINED BY THE PLAN BELOW
DE TAILS OF
DIE ARE. THE MORE ACCURATE WILL THE LINE BETWEEN C&F BE SET OUT