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OF THE OLD KIND OF FIELD-BOOK.
In surveying with the plain table, a field-book is not used, as every thing is drawn on the table inimediately when it is measured. But in surveying with the theodolite, or any other instrument, some kind of a field-hook must be used, to write down in it a register or account of all that is done and occurs relative to the survey in hand.
This book every one contrives and rules as he thinks fittest for himself. The following is a specimen of a form which has been forinerly used. It is ruled into three columns, as below,
Hire al is the first station, where the angle or bearing is 105° 25'
On the left, at 73 links in the distance or principai line, is an offset of 92 ; and at 610 an offset of 24 to a cross hedge. On the right at 0, or the beginning, an offset 25:0 the corner of the field ; at 248 Brown's boundary hedge commences ; at 610 an offset 35 ; and al 954, the end of the first line, the o denotes its terminating in the hedge. And so on for the other stations.
A line is drawn under the work, at the end of every slation line, to prevent confusion.
Form of this field. Book.
on the right. Distances.
Then the plan, on a small scale drawn from the above fieldbook, will be as in the following figure. But the pupil may draw a plan of 3 or 4 cimes the size on his paper book The dotted lines de note the 3 chain or measured lines, and the black lines the boundaries on the right and left.
But some skilful surveyors now pake use of a different method for the field-book, namely, beginning at the bottom of the page and writing upwards ; sketching also a boundary on either hand. resembling the parts near the measured lines as they pass along; an example of which will be given further on, in the method of surveying a large estale.
In smaller surveys and measurements, a good way of setting down the work, is, to draw by the eye on a piece of paper, a figure resembling that which is to be measured ; and so writing the dimensions, as they are found, against the corresponding parts of the figure. And this method may be practised to a considerable extent, even in the larger surveys.
Another specimen of a field-book, with its plan, is as fol. lows; being a single field, surveyed with the chain, and the theodolite for taking angles; which the pupil will likewise draw of a larger size. Ο Α
268 40 230
50 470 48 572
0 846 30 860