A treatise on surveying, comprising the theory and the practice ; (1887)
Gillespie, W. M. (William Mitchell), 1816-1868, Staley, Cady, 1840- [from old catalog] ed · New York, D. Appleton and company · leaf 143
tended direction of the north and south line may be parallel to oneof the sides of the board. The inner side of the stock of the T-square beingpressed against one of the other sides of the board and slid along, the edgeof the long blade of the square will always be parallel to itself and to… … straight-edged ruler, and slide alongagainst it the outside of the stockof a T-square, one side of the stockbeing flush with the blade. A parallel ruler may also beused, one part of it being screweddown to the board in the properposition. If none of these means are athand, approximately parallel…
Surveying
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