This sixth edition is a complete revision. It has been entirely reset thus providing the opportunity to discard obsolete material re-write where necessary or incorporate portions of the previous edition that seemed suitable having regard to present-day requirements of the land surveyor and the civil engineer. The appendices that had been added to the fifth edition have disappeared and new material is in its proper places in the chapters. This procedure may have resulted in a patchwork and it is hoped that this structure will not be too obvious to the reader.This edition mention may be made of the increased attention given to elementary geometrical optics in consideration of modem developments of optical reading systems which make extensive use of reflecting prisms and the parallel-sided plate device. Some obsolete or nearly obsolete instrumental features are no longer included; it can be assumed that any modem telescope has internal focusing and zero additive constant for tachymetry. The accounts of the nature of propagation of errors especially in traversing seemed to need some re-writing. Mention is made of the use of mechanical computation referring only to the simplest types of calculating machines.
.png)
.png)
