Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 137
nown, but in many surveys merely the magnetic meridian is taken; in thesecases this line is simply represented with half of the barb of the arrow atthe north point, and on the opposite side of the line from the true meridian. Scales on drawings which are to be reproduced by photography shouldalways… … ORTHOGRAPHIC PROJECTION.
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from Memorials of Lostwithiel [and of Restormell]: collected and contributed. Taken from the writings of Leland, Carew ... and others. [The preface signed: F. M. H., i.e. F. M. Hext. With MS. insertions (1891)](https://img.insideoutlibrary.com/img/200/bl-bl_001552493_0-144-1.webp)
