Transcriber's Note:
Punctuation has been standardised, and possible typographical errors
have been changed.
Archaic, variable and inconsistent spelling and hyphenation have been
preserved.
Bold text is surrounded by =equal signs= and italic text is surrounded
by _underscores_.
Footnotes appear at the end of their respective chapters.
SURVEYING AND LEVELLING
INSTRUMENTS
SURVEYING AND LEVELLING
INSTRUMENTS
Theoretically and Practically Described.
FOR CONSTRUCTION, QUALITIES, SELECTION, PRESERVATION,
ADJUSTMENTS, AND USES; WITH OTHER APPARATUS AND APPLIANCES
USED BY CIVIL ENGINEERS AND SURVEYORS IN THE FIELD.
BY
WILLIAM FORD STANLEY
OPTICIAN, MANUFACTURER OF SURVEYING AND DRAWING INSTRUMENTS,
AUTHOR OF A TREATISE ON DRAWING INSTRUMENTS,
PROPERTIES AND MOTIONS OF FLUIDS, NEBULAR THEORY, ETC.
_FOURTH EDITION_
REVISED BY H. T. TALLACK.
LONDON: E. & F. N. SPON, LTD., 57, HAYMARKET, S.W.
NEW YORK: 123, LIBERTY STREET
AND OF
W. F. STANLEY & CO., LIMITED
286, HIGH HOLBORN, LONDON, W.C.
1914
PREFACE TO FIRST EDITION.
Notes were taken for many years before the production of this work of
queries that came before the author for reply relative to functional
parts of surveying instruments. These bore most frequently reference
to optical and magnetic subjects, and to the qualities and action
of spirit level tubes, also occasionally to graduation and the
qualities of clamp and tangent motions. It was therefore thought that
it would be useful to give notes upon these subjects in detail as
far as possible in the early chapters. As the work proceeded it was
found that this plan saved much space in avoiding the necessity for
separate descriptions when parts of complex instruments were afterwards
described.
To show the state of the art and render the work useful, it was
necessary that the structure of surveying instruments should be given
with sufficient detail to be worked out by the skilful manufacturer.
Beyond this it was thought to be most important that the professional
man, who must have limited experience of the qualities of workmanship,
should be supplied with as many simple tests as possible for assuring
the qualities of the instruments he might purchase or use, with details
also of their adjustments. This matter is therefore carried into detail
for one instrument at least of each class, as very little general
information is to be found on the subject in our literature. In fact,
large groups of instruments in extensive use, such as those used for
mining surveying, and subtense measuring instruments, have remained
heretofore nearly undescribed in our language.
The technical principles followed in working out details in these pages
are given by illustrations of such parts of important instruments
as present any difficulty of observation from an exterior view of
the engraving of the entire instrument. The plans of construction
in general use are selected for illustration. Certain constructions
that are liable to failure are pointed out. Many recent improvements
in instruments are recognised and some are suggested, but no attempt
has been made to record the little differences of construction, often
meritorious, which give only a certain amount of style to the work of
each country and of each individual. Upon this point it must occur that
the work done in any workshop must vary from other work according to
the skill and judgment of the master. It is intended, therefore, that
distinctly typical instruments only should be described, in a manner
that details may be worked out therefrom. To make this matter as clear
as possible, with few exceptions these pages were written with the
instruments described upon my table, and the illustrations, when not
taken directly from the instruments, were taken from workshop drawings
to a reduced scale.
In practice it is found that instruments performing similar functions
may be very much varied in construction, bearing reference frequently
to the conditions under which they are to be used. The same may be
said of the functional parts of instruments. We may also observe that
English instruments differ in detail from foreign ones, and upon this
point there is no doubt much may be learned by comparison of some
details of English with foreign work, although our own is admitted
to rank high. Comparisons are therefore freely made in the following
pages, and suggestions offered after study abroad of foreign work, and
careful inspection of nearly the whole literature upon the subject,
in which it is very observable that some modern continental books,
treating upon parts of the subject, are much in advance of our own.
The surveying instruments described in these pages are nearly
limited to those used in the field. Instruments for plan drawing and
calculation of areas, which the surveyor uses in the office, have been
described in the author's work on Drawing Instruments (now in Seventh
Edition), to which this is intended to be the complement of the subject.
To render the work as complete as possible, it was thought necessary
to give briefly the manner of using many instruments in practical
surveying. This part of the subject, from the author's very limited
experience in the field, is largely taken from inspection of the best
works on surveying. The author, however, is very pleased to acknowledge
the kindness of many professional friends for assistance on this and
many other points, and for historical notes. For the description of
the 36-inch theodolite, given in Chapter VII. (now X.), the author is
indebted to the late Col. A. Strange, F.R.S., who gave every detail of
his design and discussed many points. The author is also indebted to
Mr. Thomas Cushing, F.R.A.S., Inspector of Scientific Instruments for
India, who has given information and his opinions upon many subjects
from his large practical experience. Also to Prof. George Fuller, C.E.,
who has kindly read proofs, examined formulæ, and made some technical
points clearer. Also to Mr. W. N. Bakewell, M.Inst.C.E.; Major-General
A. De Lisle, R.E.; Right Hon. Lord Rayleigh, F.R.S., for assistance on
several technical points.
In this First Edition, entirely from manuscript, there will no doubt
be errors and omissions; therefore the author will feel obliged by the
receipt of any notes that he may make use of for future corrections,
should another Edition be demanded.
W. F. S.
GREAT TURNSTILE, 1890.
PREFACE TO THIRD EDITION.
The note at the end of the First Edition of this work referred to
on the preceding page has brought the author many letters from
professional men, who have kindly taken interest in the work by
offering suggestions which are now incorporated as far as practical in
this Edition, and for which thanks are tendered.
One important improvement of late years in the construction of
surveying instruments is due to the greater perfection of modern
machinery, and the adoption of special machines to shape out many
parts of the work from the solid which were formerly screwed together
in many pieces, which made the instruments heavier and also liable to
become loose in parts by jars, so as to cause the necessity of frequent
readjustments.
Another important improvement in modern surveying instruments is in
their lightness, due to the discovery of permanent aluminium alloys, by
which many parts of instruments that are shaped out in the solid may be
reduced to one-third the weight of the gun-metal castings formerly used
entirely for these parts.
In the present Edition, which represents forty-seven years of
experience of the author's life devoted to the details of the subject,
it is hoped that some permanent improvements in surveying instruments
may be shown, and that many new designs now first described, founded
upon this experience, may merit trial.
The author is pleased to acknowledge the zealous aid his working
manager and at present co-director, Mr. H. T. Tallack, has given in
perfecting this work to bring it to its present state.
W. F. S.
GREAT TURNSTILE, 1901.
PREFACE TO FOURTH EDITION.
Since the publication of the Third Edition of this work, the author
has been taken from us, and it has fallen to my lot to revise it and
bring it up to the present time. This work I have approached with
the greatest diffidence, having to follow one who had such profound
knowledge of the subject, and I have earnestly endeavoured, as closely
as possible, to act as I think he would have done had he been alive,
and having enjoyed over twenty years of the happiest and closest
business relations with him--actively co-operating in bringing many of
the instruments to their present state, I venture to hope that I have
to some extent carried out what his wishes would have been.
I have carefully read over and corrected the whole work, and the
additions to it are only in the nature of bringing it up to date.
H. T. TALLACK.
286, HIGH HOLBORN,
_June, 1914._
CONTENTS.
CHAPTER I.
PAGE
INTRODUCTION:--Historical Sketch--Classification of the Subject--
Purposes and Qualities of Instruments--Workmanship--Metals--
Aluminium--Framing--Tools--Axes of Instruments--Soldering--
Finishing--Bronzing--Lacquering--Graduating--Engraving--Style--
Glass-Work--Woodwork--Lubrication--Preservation of Instruments--
Packing 1