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ent parts of the line, so as to facilitate the forwarding of supplies, and, in short, acquire the greatest amount of knowledge of the country in the least possible time. Upon his report depends the

PRELIMINARY SURVEY,

the party for which should consist of a chief, a transitman, two levelers, two rodmen, a topographer, one or two picketmen, two chain men, five axemen for the line, and one for each leveling party, three to six or even eight packmen, and sometimes a commissariat officer and an explorer.

choose some well-marked point, set the cross hairs upon it a little before dark, and see that no one disturbs the transit between that time and the time when the observation is to be taken, the hour for which can be found in the Nautical Almanac. It is usual to observe the star when at its greatest eastern or western elongation, but it can be observed when at its maximum depression below or elevation above the pole, when the instrument is provided with a tangent screw to produce a slow motion in a vertical plane. In the latter case no correction is required, so when the star has reached As in most preliminary surveys, the its greatest elevation or depression, duties of any one of these officers are which can be ascertained by keeping the substantially the same. The instructions intersection of the cross hairs on the star, of the chief engineer of the Canadian being careful never to pass it, and noting Pacific Railway to the Staff may be when it appears to cease rising or falling, taken as a general illustration of their all that is necessary is to take the readcharacter. The gentleman placed at the ing of the horizontal circle, which will head of a party is required to take gen- give the angle that the line from the eral charge of it, and is held responsible terminus to the point chosen makes with for the execution of all instructions, as the true north. In observing the greatwell as for the maintenance of proper est elongation, keep the vertical hair on discipline in the party. Every member the star and note when it appears to of the party is under his charge and must cease changing its azimuth, then take obey his orders. In conducting the survey, he is expected to be at its head every day, exploring in front and to the right and left of the line, in order to see what obstacles may be in the way of the same, and, if serious, decide as to the best manner of avoiding them. When he finds it necessary to leave the party, or in the event of illness, he should nominate the person to act in his place for the time being; in the event of his failing to do so the transitman should take charge.

The duty of the transitman is to run the instrument, keep the notes, and in case there is no topographer, to take the topography.

The duty of the first leveler is to make a profile of the line and cross sections; that of the second leveler is to check the bench marks and to assist in cross-sectioning.

The principal duty of the others of the party is to obey all orders with diligence and to the best of their ability.

Before starting the survey the transit should be set up over the terminus and a true north and south line determined by means of an observation of the pole star. To do this, place the instrument at zero,

the reading, which will be the angle that the above-mentioned line makes with the vertical plane through the star at its greatest elongation. The correction for this angle can be found by a very simple rule given in the Nautical Almanac, and is to be added, if the star lie between the pole and the line, and to be substracted if it does not. Should the line lie between the pole and the star, this will give a negative result, which shows that the angle so obtained is to be laid off from the pole towards the star; i. e., if the elogation be east, the bearing given by the minus angle will be east. It is easily seen that the latter method is by far the better, for it is necessary to use only the horizontal tangent screw (the one which gives the upper motion, of course), while in the former both the horizontal and vertical screws have to be turned at the same time. Having found, then, the true bearing of a fixed line, the true bearing of the initial line of the survey can be easily ascertained by measuring the horizontal angle between the two lines.

Suppose the party all ready to start and the initial bearing taken. The axemen go ahead clearing the line and the

chainmen follow, driving stakes about three feet long and two inches wide firmly at every hundred feet, numbering them consecutively, with red chalk as they go. When it is necessary to change the instrument, either on account of the distance of the picketman, who has been keeping the axemen on line, a sudden rise or fall of the ground or a desired change of direction, the transitman gives the signal previously agreed upon for "hub," the picketman chooses a convenient spot for setting up and finds "point" on the line into which one or two of the axemen drive a stake from four to six inches in diameter, and from one to six feet long according to the quality of the ground, and the picketman finds "point on hub" into which he drives a nail.

nearly over the nail by driving down first one leg and then another, then moving the feet of the tripod until the point of the plumb bob exactly covers the nail. If the instrument having a shifting head much time and trouble will be saved. Hubs should be placed at the summits and bases of hills, so as to avoid as much chopping and moving of the instrument as possible. At intersection points the hub-stakes should be marked "apex," and the angle to right or left should be written on another of the squared faces. The best kind of a hub is the stump of a tree that comes directly on line, for it cannot be knocked out of place. In running through comparatively level country it is well to keep as much as possible to the low ground without lengthening the line greatly or making it too crooked.

It is to be remembered that the survey is not a final one, so that it does not pay to turn out for a small ridge, but to go over it and take a cross section on the summit to where it tails off. In case of trying to reach a summit, it is necessary to follow the contours of the hills so as to obtain a gradual rise. In hilly country where the line rises and falls in long stretches, the best way to proceed is to follow up a stream to near its source, then cut across the divide and follow down another stream on the other slope. If the banks of a river are high, a good crossing can often be found by going up stream, where they are usually lower. In crossing a lake on the ice soundings should be taken, as it might be found desirable to drain the lake.

The transitman then sets the back picket, which in bush work is a small straight sapling whitened on one side, with a cross-piece eight or ten inches long, held in a cleft near the top, picks up his instrument, moves on to the new hub, over which he sets up, sights to his back picket, reverses his instrument and starts the axemen and chainmen to work. Before giving hub again, the transitman should sight once more to the back picket in order to satisfy himself that his instrument has not been moved, and if uncertain of the adjustment should turn the instrument round 180° by means of the lower movement, sight to the back picket, reverse and give "second point on hub." If this coincides with the first one all right, if not, then the distance between the two (measured, of course, Offsets usually are taken at right at right angles to the line) must be bi- angles to the line, but sometimes inclined. sected accurately and the nail be driven Short ones can quickly be turned off by at the point of bisection. This is, in standing on the centre line, stretching fact, performing the second adjustment the arms at full length along the line, of the transit. Beside each hub, at a then bringing them suddenly together; distance of about three feet, should be with a little practice a right angle can driven a large stake called "hub stake," "thus be turned quite accurately. For five feet long, at least five inches in diame- long distances it is necessary to use an ter and squared at the top. On it should instrument of some sort, a cross head be written the exact chainage of the being as good as any. Offsets are needed point on hub, and the distinguishing to locate the bases of hills and the edges mark of the survey party, which is usu- of streams. Traverses of ridges or rivers ally one or two letters. In setting up in are most easily made with the compass, swampy ground, "legs" or long heavy provided there is no local attraction, by stakes should be driven flush with the setting up at every alternate station and surface of the ground, in order to pro- reading the bearing of both lines intervide a tolerably firm set up' " for the secting at that point. The compass is nstrument. The plumb bob is brought sometimes used on the main line in level

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country where there is no great local attraction. Very often there is no instrument used at all, except at the angles, the long tangents being run in by pickets. It is surprising with what accuracy work can be done by the compass and pickets in a comparatively level country. Running a picket line in the bush is quite a different affair from what is taught at the R. P. I. during the chain survey, it may therefore be well to describe the operation: The pickets are thin straight saplings, about five and a half feet in length, brought to a long fine point at the top, and sharpened at the lower ends for pushing into the ground. The tops of two of them are set on line by the instrument about fifty feet apart; a third is then set about fifty feet farther on, the top being brought exactly on line with the others. A check on the work can always be obtained by glancing back along the line and ascertaining if the last three or four pickets are in one straight line. A pair of field glasses is of great assistance in picketing. To "tie on" to an old line, set a hub on each side of it, drive a nail in each along the line of sight of the instrument, and stretch a string tightly between the nails. Next take up the instrument, set it up on the old line, and in its direction, and sight to a picket moved along the string until covered by the vertical hair; then drive a hub and set a nail at the point thus found.

has a ball and socket joint, by means of which it can be set up in places where it would be impossible to use an ordinary Y level. The telescope being an inverting one may cause a little trouble at first, but it does not take long to become accustomed to that. The best kind of rod is a piece of well-seasoned pine wood sixteen or eighteen feet long, four inches wide and one and a-half inches thick at bottom, three inches wide, and threequarters of an inch thick at top, and divided into tenths and half-tenths. The form of level book should be that shown in the figure below:

Sta. B.S. Int. F.S. H.I. Elev. Remarks.

The F. S. column is for turning points alone, so that by adding up the B. S. and F. S. columns, subtracting one from the other, and comparing the remainder with the difference in elevation of the starting and final points, a check on the accuracy of the book can be obtained. Bench marks should be made about every fifteen hundred feet, and should be well defined so as to catch the eye readily. The ordinary method of making them is to blaze the side of a tree or stump, drive a nail into a projecting knob on the root and write the elevation of the top of the nail on the blazed part, together with the distinguishing mark of the survey party. The exact location of the bench should be noted in the level book in the column for remarks. To make a good bench mark without the use of a nail, slice off the side of a stump to very near the bottom, and bring the remaining part

After the transit party has made a good start, the levelers commence work; they should never approach the transit closely enough to disturb the back picket. If the second leveler finds a difference of more than one-tenth of a foot between benches, the levels should be rechecked. The speaking rod is almost exclusively used in bush work; it is much better than the target rod for rapidity, and the leveler is not at the mercy of his rodman, who may often be too ignorant to read the rod. Care should be to a rounded apex. taken to equalize back sights and fore sights, and neither should exceed for accurate work four hundred feet. It is possible to read an ordinary rod on a clear day at eight or nine hundred feet, but one cannot rely on levels so taken. The best kind of level for rapid work, as far as my experience goes, is the Pastorelli. It is fourteen inches in length and

The leveler should note every stream and river crossed, its size, direction, level of surface, difference of levels between high and low water, velocity of current, probable discharge, and any peculiarities which it may seem to possess. While in the field it is not necessary to work out the elevations of intermediates; it is sufficient to know the height of instrument

and the elevations of bench marks. should be made every night and the latiEvery evening the leveler should "make tude and departure worked out. Checks up "his book and plot the profile. Lev- on the work should be made as often as eling can be done very rapidly in win- possible. The check for deflections is ter, as traveling on snow shoes is so made by taking an observation of the much easier than ordinary walking in pole star every ten or fifteen miles and the bush. The uncertainty as to the comparing the reckoned true bearing shape of the ground beneath the snow with the observed, after making the makes it sometimes difficult to get a proper correction for conveyance. This good set-up, but if the three legs of the is found as follows: Let n the numtripod be kept vertical and the snow be ber of miles in a degree of longitude, a packed well about them, the instrument quantity depending upon the latitude of will be kept as steady as in any ordinary the place, then will 60÷n the correcset-up. If the rodman carry a three- tion in minutes per mile of longitude. foot stake to be pushed through the Calling m the number of miles of longisnow to the ground at intermediates, and tude between the two points considered, upon which the rod is placed, much time 60m÷n will be the required correction. may be saved. In this case care should A check for the distance can be roughly be taken to add three feet each time to obtained by ascertaining the latitude and the reading of the rod. The transit longitude of various points along the book ordinarily used has one page ruled line, by observations of the stars. Checks into squares, each side representing one can sometimes be obtained by tying on hundred feet, and the other page ruled to old lines. If an error be found in the for remarks, a red line running through direction of the line, it may have been the center of each. In case there be a made by recording an angle to the wrong topographer in the party, the transitman side; to ascertain if such be the case, need make note only of the chainage, divide the error by two and see if there magnetic bearings and deflection angles, be an angle on the plot which is equal or being sure to state whether they are to very nearly equal to this result. If right or left. But if there be no topog- there be one the chances are that the rapher, it will be necessary for him to mistake was made in that way. In case keep fnll topographical notes. These the error cannot be located, it will be consist of offsets to right and left wher- necessary to go over the work again, ever necessary, contours of hills, courses commencing at the point where the next of streams, observations as to the quality to last observation was taken. Errors of timber and soil, location of ridges and lakes, etc., etc.

The first entry in a note book each morning should be the name of the person acting as transitman, leveler or topographer, as the case may be. All notes should be clearly and distinctly made in pencil on the spot; no additional notes should be entered with the original notes after the day on which the latter are written. Field notes should not be inked or changed in any way; copies of them may be made in ink and reduced levels entered in ink. This is to prevent what is called "cooking "the notes, an of fence of which no true engineer is ever guilty. Any man found tampering with the level notes or benches, or trying any scheme to make poor work pass for good, gets his discharge without any compunction on the part of the chief engineer or those who are interested in seeing work well done. A plot of the day's work

are sometimes made in reading a deflection angle, and sometimes by making a crook in the line owing to the transit being out of adjustment or level. Whenever an observation of the pole star is made, the variation of the needle should be noted. As the survey progresses, the engineer in charge should project a location line on the map by means of the cross sections taken to right and left, in order to give a general idea of where the true location of the road will be. IIe is expected to keep a diary in which to note the progress of the work each day, the difficulties overcome, and everything relating to the survey. He should see that the camp is properly supplied with everything needed, and should, if possible, have depots for provisions made at points near which the line will pass, so as to avoid packing them over the line. Camp should be moved every three or four miles, in order to avoid long walks

to the place of starting work in the one) have been handed into the office, it morning. It may be necessary during is there decided what is to be the apthe progress of the survey to forward proximate location of the line. The special instructions to the engineer in party for location is the same as for precharge; for this and other reasons, that liminary, except that there is no explorer officer should take especial care that needed. The general style of the work whenever the camping ground is changed, is the same, the principal differences bea notice be distinctly written upon a tree, ing that, as the survey is a final one, the or in some other conspicuous position, centers are run in on the curves, and containing the following information: greater care is taken in getting the ele1. The distinguishing letter of the vations of points between the stakes and on the cross sections. The subject of curves is so well treated in Henck's Field Book for Engineers that it is useless to go into it here. It will be sufficient to state that the formulæ most often employed are T-Rtan I and C=R tan I tan I, where T is the sub-tangent, R The success of the survey is materially the radius of the curve, I the angle of assisted by each man endeavoring to intersection and C the crown distance. save as much time as he can. A few The latter is used as a check for the corhints as to how this can be effected may rectness of the first half of a curve, be of use. Before moving the instru- which is so long as to require several

survey.

2. The number of the camp.

3. The date of removal of camp. 4. The probable direction and distance to the next camping ground.

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5. The name of the engineer in charge of the party.

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ment the transitman should, if he wish to prolong the line, set two pickets on line beyond the new hub, in order that the axemen near continue their chopping while he is moving on and setting up. He can set his own back picket, if it be left ready for him, by placing it close behind the instrument and bringing the cross to the level of the eye-piece. As soon as point for hub is called for, one of the axemen should commence making a hub, and if the ground require it, legs for the instrument. The fore chainman, who carries a light axe, should occupy himself in cutting stakes when not busy chaining.

There is a great variety of opinion as to what transit is the best for bush work. Some engineers prefer those of English manufacture, others those made in this country. The most satisfactory that I have ever tried is one of Gurley's manufacture.

LOCATION.

After the results of the different preliminary surveys (if there be more than

changes of instrument. The number of stakes put in at one setting-up depends altogether upon the natural features of the ground, the degree of the curve and the size and thickness of the timber. In running around a rocky bluff it may be impossible to see more than one hundred feet at a time, especially if the angle of deflection be large; in which case it would be well to put in stakes fifty feet apart.

In Plate I., Fig. 1, suppose the transit to be set up at B to run in the curve BCDEF, &c., from the initial tangent AB. If the points C, D, E and F are all to be located from the point B, it will be necessary to clear out all the timber on the area included between the chords BC, CD, DE, EF and FB. Now if the curve be an easy one, that is of light curvature, say thirty minutes, that area will not be great, so that it would take less time ordinarily to do that amount of chopping than to make a new set-up at D, in which case the areas of the triangles BCD and DEF only would have to be cleared. If the curve were heavy

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