others, for courtesies extended to him in making personal examination of their processes and methods; and to the last named especially for opportunities afforded, and assistance rendered, in experimental work. He is also indebted to Prof. Edwin J. Houston, of Philadelphia, for the revision of the proof-sheets of the chapter on Dynamo-Electric Machines.

To facilitate reference and investigation, a copious list of patents -American and British-relating to the subject of electro-metallurgy has been carefully compiled and is given in the Appendix. The very full index will also be appreciated by those who may have occasion to consult it.

W. H. W.

PHILADELPHIA, Nov. 5, 1883.

CONTENTS.

HISTORICAL FACTS RELATING TO ELECTRO-METALLURGY.

Practical Application of the Galvanic Current, by Sir Humphry Davy,

1808; Discovery of Professors Wagner and Jacoby, on the practical

application of the Battery, in Plating and Copying, 1830; History

of this discovery

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Discoveries of De la Rue, 1836, and Dr. Golding Bird

First successful Application of the Deposition of Metals by Galvanic

Action, by Prof. Jacoby, 1838; C. J. Jordan's Experiments, 1839;

T. Spencer's paper on Electrotype Process, and the Deposition of a

Metallic Surface on a model of clay, wood, or other non-metallic body. 19

Experiments of Prof. Boettger, 1840-41; and John Wright of Bir-

mingham. Patent of M. de Ruolz, 1840, for Electro-gilding and

Silvering by means of solutions of the double cyanides and ferro-

cyanides

20

Rapid progress of the Art; American Experimentalists; use of Electro-

type plates and letter-press, by Daniel Davis, of Boston, 1842; Re-

production of an engraving for a magazine, by Joseph A. Adams of

New York; Electrotype borders around engravings in Harper's Illus-

trated Bible in 1843; Rapid and important development of the Art. 21

PART I.

THIN METALLIC DEPOSITS.

CHAPTER I.

OBJECT OF THE HYDROPLASTIC ART.

Two orders of phenomena comprised in the Art of Depositing Metals by

the Wet Way; Gilding by Simple Immersion; Electro-Gilding; the

two modifications of Electricity recognized by physicists; Static

Electricity; Dynamic Electricity

Operations of deposition by Simple Immersion and by Electro-deposi-

tion

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24

Definitions; Electro-Chemistry; Electro-Metallurgy; Electro-Metal-

lurgy proper; Electrotyping; Electro-Plating.

CHAPTER II.

CLEANSING.

Cleansing Copper and its alloys; cleansing by fire or by alkalies

Dipping

Apparatus used.

Dipping in old Aqua fortis

Dipping in strong Aqua fortis

Three kinds of Nitric Acid of 360 in the market; Mat Anglais

Aqua fortis for bright dipping; Acid mixture for bright dipping

Preparation of the Dipping Liquid

Whitening Bath .

Acid mixture for dead dipping

Hot Bath for dead lustre

Dipping in Nitrate of Mercury (“ quicking" solution); use of the Nitrate

of the Suboxide of Mercury (Mercurous Nitrate); proportion of

Mercury Salt to be used

Behavior of the articles in the "quicking" solution; a test of the thor-

oughness of the cleansing operation; reviving the "quicking" solu-

tion; no intervals should take place between the various operations

of cleansing; résumé of operations

The "stripping" liquids for removing the precious metals

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The practice of using Nitric instead of Sulphuric Acid for pickle .

CHAPTER IV.

SCRATCH-BRUSHING.

Scratch-Brushing; various kinds of Scratch-Brushes

Shallow wooden tub for the solution; various liquids employed

Mode of proceeding with small articles of Jewelry, and with large arti-

Circular Scratch-Brushes; Scratch-Brush Lathe .

Lathe for pieces of small size

To remove the twisted wire ends of a Scratch-Brush

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The treatment of Scratch-Brushes

Importance of Scratch-Brushing; Buffing Wheels used in Scratch-

Brushing

CHAPTER V.

CLEANING BY ATTRITION (Tumbling).

Small articles which cannot be Scratch-Brushed, cleaned by Attrition;

how the operation is performed

Performing the operation in water

The Tumbling-box

CHAPTER VI.

GOLD VARNISH.

The operation of Gold varnishing

Different kinds of Varnish

CHAPTER VII.

CLEANSING ZINC, ETC.

Cleansing Zinc.

How the operation is performed; Mixture for cleansing

Amalgamating the Zinc

Cleansing Lead, Tin, etc.; Cleansing Cast-iron.

Cleansing Wrought Iron; Cleansing Steel; Composition of Solution

Gilding and Silvering Iron and Steel without an intermediary coating

of Copper

CHAPTER VIII.

GALVANIC BATTERIES.

The Apparatus to which this name is applied; phenomena connected

with the Production of the Electric Current

Modification used by Electro-gilders of Watch and Clock Works and

Grove's Battery

The Grenet Battery; the Marie-Davy Battery; Smee's Battery
Roseleur's Modification of this Battery

The Léclanché Battery; this Battery less powerful than either the
Bunsen, Archereau, or Grove Battery

Construction of the Léclanché Battery

CHAPTER IX.

DYNAMO-ELECTRIC MACHINES.

Great impulse received by Electro-plating from the Invention of

Dynamo-Electric Machines

The Wilde Machine.

Efficiency of the Wilde Machine; An important step in the Simplifica-

tion of these Machines, "the reaction principle;" Serious difficulty

encountered in applying the Dynamo-Electric Machine to Electro-

plating.

M. Gramme's Improvement in the Dynamo-Electric Machine by using
an Iron Ring as a revolving Electro-Magnet; the Gramme Machine;
to start the Machine

Description of the Machine and its Power

Comparative performance of the Wilde and Gramme Machines

Tables of the Results of Comparative Experiments with the Gramme

and Wilde Machines

Relative amount of work done by the Battery, and by the Electro-mag-
netic Machines

The Brush Machine.

Van der Weyde's Comparison between the Gramme and the Brush

Machines

Performance of the Brush Plating Machines

Performance of one of these Machines in Electrotyping

The Arnoux-Hochhausen Plating Machine with a Siemens' Armature

and Automatic Switch for regulating the Current according to the

Surface of the work in the Bath, and preventing the machine from

"Reversing"

The Mather Dynamo-electric Machine

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The Müller Machine; the Siemens' Machine, comparative merits of

these Machines; need of tests to determine which type of Machine

is best adapted for metallurgical purposes; the Dynamo-electric

Machine now practically the sole source of Electric Current in Elec-

tro-plating, having supplanted the Voltaic Battery; has contrib-

uted largely to the extension of the art of Electro-plating; Its impor-

tance in connection with Nickel-plating .