A text-book of assaying : $b for the use of those connected with mines.

E-text prepared by Peter Yearsley, Josephine Paolucci, and the Project
Gutenberg Online Distributed Proofreading Team (https://www.pgdp.net/)



Note: Project Gutenberg also has an HTML version of this file which
      includes the original illustrations and in which the chemical
      equations are easier to read.
      See 18751-h.htm or 18751-h.zip:
      (https://www.gutenberg.org/dirs/1/8/7/5/18751/18751-h/18751-h.htm)
      or
      (https://www.gutenberg.org/dirs/1/8/7/5/18751/18751-h.zip)


Transcriber's Note:

   Text:

      Words surrounded by a tilde such as ~this~ means the word is
      in bold face.

      Words surrounded by underscores like _this_ means the word is
      in italics in the text.

      Letters in brackets with an = sign before it means that the
      letters have a macron over them, e.g. H[=A=c] signifies that
      the Ac has a macron over it.

   Numbers and equations:

      Parentheses have been added to clarify fractions.

      Underscores before bracketed numbers in equations denote a
      subscript.

      Superscripts are designated with a caret and brackets, e.g.
      11.1^{3} is 11.1 to the third power.

      The symbol .'. designates the symbol usually used for therefore
      (three periods in a triangle shape).

      A down arrow is represented by a vertical line over a capital
      V. Like this:  |
                     V

   Minor typographical errors have been corrected. Footnotes have
   been moved to the end of the chapter, and all advertisements
   have been moved to the end of the book.





A TEXT-BOOK OF ASSAYING:
FOR THE USE OF THOSE CONNECTED WITH MINES.

by

C. AND J. J. BERINGER.

Revised by

J. J. BERINGER,

Assoc. of the Royal School of Mines; Fellow of the Chemical Society and
of the Inst. of Chemistry; Principal of the Camborne Mining School; and
Late Public Analyst for the County of Cornwall.

With numerous Diagrams and Tables.

Ninth Edition.







London:
Charles Griffin and Company, Limited,
Exeter Street, Strand.
1904.
[All rights reserved.]




PUBLISHER'S NOTE TO THE NINTH EDITION


The continued popularity of the present work, the last edition of which
was published only a little over a year ago, continues to be a source of
gratification to the publishers, who have much pleasure in issuing the
present edition.

_January 1904._


PREFACE TO THE SIXTH EDITION

The principal changes in this edition are additions to the articles on
Gold, Cyanides, and Nickel, and a much enlarged Index. The additional
matter covers more than forty pages.

J. J. BERINGER.

CAMBORNE,
_January 1900._




PREFACE.


The Text-book now offered to the public has been prepared to meet the
existing want of a practical "handy book" for the Assayer.

To mining men the word "assaying" conveys a sufficiently clear meaning,
but it is difficult to define. Some writers limit it to the
determination of silver and gold, and others imagine that it has only to
do with "furnace-work." These limitations are not recognised in
practice. In fact, assaying is becoming wider in its scope, and the
distinction between "assayers" and "analysts" will in time be difficult
to detect. We have endeavoured rather to give what will be of use to the
assayer than to cover the ground within the limits of a faulty
definition.

At first our intention was to supply a description of those substances
only which have a commercial value, but on consideration we have added
short accounts of the rarer elements, since they are frequently met
with, and occasionally affect the accuracy of an assay.

Under the more important methods we have given the results of a series
of experiments showing the effect of varying conditions on the accuracy
of the process. Such experiments are often made by assayers, but seldom
recorded. Statements like those generally made--that "this or that
substance interferes"--are insufficient. It is necessary to know under
what conditions and to what extent.

Students learning any particular process cannot do better than repeat
such a series of experiments. By this means they will, at the same time,
acquire the skill necessary for performing an assay and a confidence in
their results based upon work under different conditions.

The electrolytic method of copper assaying given under _Copper_ is a
modification of Luckow's; it was introduced by us into the offices of
the Rio Tinto Copper Company, and has been in use for many years with
success. This modification is now employed in copper-works in Spain,
Germany, and England, and is used in place of the dry assay for the
commercial valuation of copper ores.

We have adhered to the gram and the "c.c." as the units of weight and
volume. Those who prefer working with grains and grain-measures can use
the figures given, multiplied by ten. For example:--When 1 gram is
mentioned, 10 grains should be used, and 10 grain-measures take the
place of 1 "c.c."