Cellulose

Front matter

Class \0SH5 Book__ 2M^

Gsi}yn§\tW^

CfOPJfRICHT DEPOStn

I. Cellulose

PAGE

Distribution of cellulose throughout nature; Structure of plants; Change of cellulose vessels into wood vessels ....... 1

Occurrence of cellulose; Occurrence of cellulose in the animal and vegetable kingdoms; Cellulose formerly at our disposal; Straw as a material for cellulose; Deficiencies of pulp and paper from straw ... 2

Employment of wood for the preparation of cellulose, a modern achievement; Chemical nature of wood; Encrusting substance of wood; Cotton. 3

Fruit of the cotton plant, described and illustrated; Appearance of the cotton fibre 4

Cotton fibres, described and illustrated; Determination of the value of a variety of cotton; Short-staple and long-staple cotton .... 5

Chemical composition of cotton; Otlier fibre-producing plants and natural sources of cellulose-fibres; Preparation of chemically pure cellulose from cotton; Properties of cellulose; Formula of cellulose ... 6

Percentage composition of cellr' ?e; Transformation of substances in the living plant-organism; Conversion of cellulose into soluble substances; Digestibility of cellulose by carnivorous animals and human beings . 7

Solubility of cellulose; Solvents for cellulose; Behavior of cellulose towards acids; Effect of water upon cellulose ...... 8

Hydrocellulose and its composition; Mode of manufacture on a large scale of hydrocellulose .......... 9

R. Sthamer's process for the preparation of larger quantities of hydrocellulose . . . . . . . . . . . .10

Preparation of hydrocellulose with the use of hydrochlof-ic acid; Behavior of cellulose towards acids . . . . . . . . .11

Upon what the various processes for the preparation of alcohol from cellulose or wood are based; Action of sulphuric acid upon cellulose; Formation of amyloid .......... 12

Action of hydrochloric acid and of sulphurous acid; Action of organic acids; Chemical changes effected by nitric acid; Effect of the acid sulphites of the alkalies and alkaline earths ...... 13

Combinations formed by cellulose with organic acids; Behavior of cellulose towards alkalies; Action of caustic alkalies; Mercerization and its invention by John Mercer; Conversion of cellulose into oxalic acid . 14

(Vii)

Vlll CONTENTS.

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Behavior of cellulose at an increased temperature; Destructive distillation of cellulose and products formed thereby; Cellulose the basis-material of a large series of combinations of great technical importance . . 15

Industrial uses of cellulose; Vegetable parchment; Cellulose sulphocarbonate or viscose; Nitro-celluloses ....... 16

Artificial silk; Celluloid; Conversion of cellulose into fermentable sugar; Production of cellulose; Former sources of cellulose . . . . 17

Plants utilized for the production of- cellulose; Constitution of paper; First experiments for the purpose of obtaining cellulose from straw . 18

Experiments for the purpose of obtaining cellulose from wood, and final success in this respect .......... 19

Invention of a processs for the solution and destruction of the lignin or encrusting substance of wood; Substances used for this purpose; Experiments for the production of textile threads from cellulose; Phases of the historical development of the production of cellulose from wood. 20

Possibility of obtaining cellulose from wood in the form of textile fibres. 21

II. Wood-stuff or Mechanical Woob-Pulp

Definition of the term wood-stuff or mechanical wood-pulp; Chief use of wood-stuff; Origin of the fundamental idea of the process of wood

grinding; First patents granted for the process ..... 22

Execution of Voelter's process of wood grinding; Wood for grinding;

Most suitable varieties of wood ........ 23

Preparation of the wood to be ground; Machine for cutting away the

bark, described and illustrated ........ 24

Machines for the removal of the knots, described and illustrated . . 25

Spliting machine, described and illustrated ...... 26

Wood-grinding machines; Essential parts of every kind of machine for

Voelter's grinding machine, described and illustrated . , ... 28 A. Oser's grinding machine, described and illustrated . . . .30

Freitag's grinding machine, described and illustrated . . . - 31 Abadie's grinding machine, described and illustrated . . . .32

Liebrecht's grinding machine ......... 33

Use of hydraulic pressure for pressing the wood against the grindstone;

Water used for grinding; Filtration of the water used for grinding . 34 Sorting the ground mass; Sorters for sorting the wood-stuff; Voith's

shaking sieves, described and illustrated ...... 35

Mode of operation of the shaking sieve; Use of cylinder sieves . . 36

The refiner, described and illustrated ....... 37

Use of corrugated rolls for the reduction of particles of wood . . .38

Recovery of the finest particles of pulp ....... 39

Dehydration of the pulp; The board-machine; Mode of obtaining thoroughly dried pulp 40

CONTENTS. IX

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Pulp for transporting long distances; Drying apparatus; Arrangement of the apparatus for drying pulp ........ 41

Properties of wood-pulp; CI. Winkler's experiments; Change of color of pulp 42

Bleaching agents for pulp; Bleaching by means of sulphurous acid; Pulp from steamed wood; Quantities of substances which pass into solution by steaming different kinds of wood . . . . . . . . 43

Combinations formed in steaming wood; Apparatus for steaming wood; Production of pulp from steamed wood . .■ .. . . .44

Microscopical examination of steamed wood; Preparation of mechanical wood-pulp by the crushing process; Chopping machines, described and illustrated ............ 45

Reduction of the small pieces of wood in a stamping mill; Usual mode of working the mass obtained from steamed wood . . . ... 47

Difference between ground wood and the original material . . .48

III

Preparation of Cellulose from Wood. ( Wood-Celltjlose, Cellulose IN THE Technical Sense of the Word, Chemical Wood-Pulp. )

Constitution of paper; Principal point in the preparation of cellulose from wood 50

Principal processes employed for the preparation of wood-cellulose; Bachet and Machard's method ........ 51

Preparation of cellulose by means of soda; First step in the manufacture; Disintegration of the encrusting substance ...... 52,

Substitution of sodium sulphite for a portion of the caustic soda; Boiling the chips of wood . . 53

Sinclair's boiler, described and illustrated 54

lingerer's boiling process ......... 55

Keegan's process ........... 56

Use of a battery for lixiviation; Contrivances for washing cellulose. . 57

Preparation of cellulose by means of sodium sulphite; Further working of the washed cellulose ......... 58

Consumption of wood and chemicals; Yield of finished cellulose from various kinds of wood; Preparation of cellulose with the assistance of sulphites (sulphite-cellulose according to Mitscherlich's process); Importance of an abundance of water; Quantity of water required . . 59

Preparation of the wood; Freeing the trunks from bark; Reduction of the wood; Woods most suitable for the preparation of sulphite cellulose . 60

Operations into which the preparation of cellulose by the sulphite process may be divided; Preparation of the sulphite solution according to Mitscherlich's process 61

Limestone for the preparation of the lye; Preparation of the sulphurous acid; Tests as to whether combustion of the sulphur is complete . . 62

The absorbing tower and its arrangement, described and illustrated . . 63

X CONTENTS.

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Arrangement of a plant .......... 65

Lye reservoirs; Causes of irregularities in the operation, and their

Boiling the wood with the lye; Boiler for this purpose, described and

illustrated; Brick work for lining the boiler, described and illustrated. 67 Mode of heating the mass in the boiler; Proportion between wood and

Test for ascertaining how much effective calcium bisulphite is still present. 69 Recovery of sulphurous acid; Washing the cellulose. . . . .70

Freeing the cellulose from admixtures; Arrangement of a stamping mill

for this purpose ........... 71

Defects of cellulose and their remedies; Cause of yellowish or brownish

color; Occurrence of white pieces not converted into fibre; Occurrence

of black particles and of larger brown bundles of fibre . . . .72 Change in color of the cellulose during washing; Preparation of cellulose

with the assistance of the electric current — Kellner's process . . 73 Apparatus used for this purpose, described and illustrated . . .74 Advantages of the electrical process; Preparation of cellulose from straw;

Preparatory operations. ......... 7-5

Cutting and winnowing the straw; Further working of the winnowed

straw; Boilers for working the straw ....... 76

Bleaching the cellulose; Yield of cellulose; Various plants which are

utilized for the preparation of cellulose . . . . . .77

Utilization of jute bagging; Mode of working jute; Utilization of exhausted

lyes and their neutralization ........ 78

Recovery of soda; Discharge of lyes into running water when working

with the sulphite process; Dilution of the lyes . . . . .79 Neutralization of the lyes; A. Frank's process; Utilization of sulphite lyes

IV. Vegetable Parchment

Change in unsized paper when subjected to the action of sulphuric acid; Chemical composition of vegetable parchment; Explanation of the parchmentizing action of sulphuric acid ...... 82

Nature of the paper to be parchmentized; Paper suitable for parchmentizing; Preparation of parchment of greater thickness . . . .83

Sulphuric acid used for parchmentizing; Use of so-called chamber acid . 84

Time required for parchmentizing; Parchmentizing apparatus . . .85

Removal of the last traces of acid adhering to the paper; Drying the finished parchment; Recovery of the sulphuric acid . . . . .86

Properties of parchment; Table showing the changes paper undergoes by parchmentizing ........... 87

Preparation of parchment of special thickness; Rendering parchment paper flexible .88

CONTENTS. XI

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Coloring parchment'[paper; Preparation of chrome glue for joining together parchment paper ^2 .-...•••• 89

Applications of vegetable parchment; Vulcanized cellulose (vulcanized fibre) , and its preparation; Process according to the patent specification. 90

Forms in which vulcanized fibre is found in commerce . . . • 91

V. Production op Sugar and AlcohoI/ from WooD-CEiiLULOSE

First experiments for the conversion of cellulose into sugar . . .93

Older methods; Zetterlund's process 94

Bachet and Machard's process ........ 95

Other methods for the production of alcohol from wood; Failure of an experiment for the production of alcohol from beech; Nature of the wood to be worked . . . . . . • . . . . .96

Varieties of wood suitable for the production of alcohol; Apparatus to be used and mode of procedure in general ...... 97

More modern methods for the production of alcohol from wood; Cutting up the wood; Conversion of the cellulose into sugar; Boiling under pressure ............ 98

Apparatus used for boiling; Tests as regards the time required for obtaining the largest possible quantity of sugar ...... 99

Removal of the hydrochloric acid; Neutralization of the sugar solution . 100 Fermentation of the sugar solution; Distillation of the fermented fluid . 101 Value of alcohol obtained from wood; Classen's process for the production

of directly fermentable sugar from wood ...... 102

A noteworthy process also patented by Classen. . . . . .104

Main point of the process ...... ... 105

Disintegration of the wood by means of chlorine or hypochlorides; Another process patented by Classen. ....... 106

Modification of Classen' s process ........ 107

VI. Preparation of Oxalic Acid from Wood-Cellulose

Materials from which the largest^yields of oxalic acid are obtained; Suitability of wood for the preparation of oxalic acid ..... 108

Mode of formation of oxalic acid; Thorn's investigations; Yield of oxalic acid from sawdust . . . . . . • • • .109

Table showing yield of oxalic acid under different conditions; Changes taking place in sawdust by treating it with mixtures of caustic alkalies. 110

Best proportions between caustic soda and caustic potash; Advantage of heating the mixture of sawdust and caustic alkalies in a thin layer . Ill

Prevention of the turbulent reaction during fusion; Capitaines and Hertlings's process 112

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Preparation of oxalic acid on a large scale; Preparation of the mixed lyes; Melting apparatus . . . . . . . • • • .113

Mode of heating; Contrivance for turning the mass while being heated . 114

Working up the melt; Utilization of the mother-lye 115

Mode of obtaining pure oxalic acid from the crude sodium oxalate . .116 Production of pure oxalic acid; Pans used for this purpose . . . 117 Production of an almost chemically pure product 118

VII. Viscose and Viscoid

Invention of these products, in 1892, by Brown, Beadle and Cross; Main point of the invention; Regulation of the progress of the conversion of viscose into viscoid .......... 119

Raw material for the preparation of viscose solution; Preparation of viscose for experimental purposes, and for working on a small scale. . 120 Preparation of viscose on a large scale; Material for this purpose . . 121 Comminution of the cellulose, and apparatus used; Quantitative proportions between cellulose and caustic soda; Recognition of the commencement of the formation of soda-cellulose. . . . . . .122

Methods used in practice for the preparation of soda-cellulose. . . 123 Soda-cellulose; Main point in the manufacture of soda-cellulose; Storing of soda-cellulose ........... 124

Injurious changes in soda-cellulose; Advantages of storing this material in an ice-house. . . . . . . . . . . .125

Products formed by the decomposition of soda-cellulose; Preparation of viscose; Properties of carbon disulphide ...... 126

Apparatus for the preparation of larger quantities of viscose; Proportion between soda-lye and carbon disulphide; Nature of cellulose sulphocar-

bonate 127

Recovery of carbon disulphide; Preparation of viscose solution . .128 Storing viscose; Vessels used for this purpose; Stability of viscose; Best temperature for preserving viscose . . . . . . .129

Shipping of viscose; Properties of viscose solutions; Recognition of the commencement of the decomposition of a viscose solution; Changes taking place in viscose solution ........ 130

Influence of temperature upon the decomposition of viscose . . . 131 Conversion of viscose into viscoid; Chief uses of viscose; Preparation of

thicker plates from viscoid ........ 132

Behavior of viscose towards metallic salts; Magnesium-viscose. . . 133 Proportional quantities of bodies added to soda-viscose for the purpose of obtaining other varieties of viscose; Preparation of viscose according to

Cross 134

Preparation of viscose according to Seidel 135

Transparent plates from viscose 136

Mode of giving a loosely- woven, thin tissue the appearance of a close and firm fabric . . . . . . . . . . . . 137

CONTENTS, Xlll

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Preparation of chemically-pure cellulose sulphocarbonate (viscose); Uses of viscose; Incorporation of pulverulent substances . -a^^ • • 138

Use of viscose in the manufacture of paper; Ammonium viscose . . 139

Advantages of the use of ammonium or magnesium viscose; Application of viscose as a size to wi'apping paper; Table showing how the qualities of the papers are effected by the addition of viscose .... 140

Viscose in the manufacture of wall paper; Advantage of its use in the manufacture of flock paper; Coating of ordinary wall paper with viscose; Imitations of leather and velvet hangings 141

Viscose in cloth printing; White design upon a colored ground . . 142

Printing color prepared with viscose; Viscose solution for marking fabrics in mills, and as a substitute for ink for marking household linen, etc.; Viscose as a size or dressing. ........ 143

Simplest mode of sizing; Addition of loading agents to the viscose; Imparting smoothness and lustre to the tissue treated with viscose . . 144

Preparation of leather-like bodies by means of viscose; Constitution of leather; Main point in the production of a satisfactory imitation of leather 145

Fabrics to be used and working them up into leather-like masses; Viscose solution for impregnating the tissues ....... 146

First step in the operation; Coloring imitations of leather; Vat for the viscose solution; Passing the fabric through the viscose solution . . 147

Conversion of the viscose into viscoid; Protection of the workmen from the gases evolved; Recovery of the carbon disulphide; Finishing and drying the fabrics. . . . . . • • • • .148

Working thick fabrics; Condition of the impregnated fabrics; Properties of the impregnated fabrics ......... 149

Uses of fabrics impregnated with cellulose; Impregnation of ordinary pasteboard with viscose solution ........ 150

Uses of such pasteboard; Felt-plates impregnated with viscose solution, and their use ........... 151

Viscose in the manufacture of artificial flowers; Mode of application; Pure viscose for especially delicate flowers ....... 152

Viscose in photography; Preparation of films from viscose . . . 153

Viscoid masses; Preparation of homogeneous viscose masses free from bubbles 154

Working of pure viscoid; Incorporation of foreign bodies with the viscose; Materials for the preparation of white masses; Masses of a pure, milk-white color and of comparatively slight specific gravity . . .155

Experiment on a small scale in mixing filling substances with viscose . 156

Properties of a viscoid mass of the proper quality; Preparation of larger quantities of viscoid masses; Mixing or kneading machine . . . 157

Shape of a kneading and mixing paddle, described and illustrated ; Mode of working the viscose solution in the mixing machine. . . . 158

Moulding the viscoid mass, and moulds used for the purpose; Moulding solid and hollow articles; Finishing and painting the articles . . 159

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Viscoid masses with cellulose or mechanical wood pulp as filling substances and their various applications 160

VIIL

Combinations formed by bringing pure cellulose in contact with nitric acid; Two distinctly marked groups of combinations; Discovery of the combinations formed by the action of nitric acid upon cellulose; Former opinions regarding the formation and composition of the combinations. 161

Modern views i-egarding the composition of gun-cotton; Formation of nitro-cellulose . . . . . • . . . . .162

Preparation of nitro-cellulose in explosive as well as soluble form; Investigations by G. Lunge and E. Weintraub 163

Effect of the presence of a very large quantity of sulphuric acid; Use of a nitrating fluid containing but a small quantity of sulphuric acid; Time required for the completion of the process of nitration .... 164

Loss in cellulose when working with a nitrating fluid heated to different degrees of temperature; Change in the structure of the nitro-cellulose; Action of nitro-cellulose towards polarized light 16&

Main objects to be attained in practice in the preparation of nitrocellulose; Products which come chiefly into question for practical purposes ............. 166-

Modes of calculating the nitrogen in nitro-cellulose adopted by the French chemists and by the English and German chemists; G. Lunge and J. Bebie's investigations; Table showing the relation between the modes of determination adopted by the French and German chemists . . 167

Table showing the influence exerted by the content of water in the acid mixture upon the process of nitration ....... 168

Typical soluble nitro-cellulose — the actual collodion-cotton; Solubility of nitro-celluloses 169^

Table showing the efiect of higher tempei-atures such as are used in the preparation of collodion-cottons . . . . . . . .170

General use of a mixture of nitric and sulphuric acids for the preparation of collodion-cotton; Figures obtained with the use of 1 nitric acid to 3 sulphuric acid ........... 171

Nitrating fluids used in the experiments; Table showing the final results of further experiments. ......... 172

Importance of paying attention to the content of water in the nitrating fluid; Experiments in this direction ....... 173-

Analyses of various nitro-celluloses; Preparation of gun-cotton; First requisite for the production of gun-cotton ; Purification of raw cotton . 174

Acid used for nitration; Use of mixtures of concentrated nitric and sulphuric acids; Former mode of nitration; Strength of nitric acid for very explosive products and for readily soluble products . . . . 175

CONTENTS. XV

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Sulphuric acid for nitration; Storage of the acids; Stoneware vessels forlj:^ nitrating purposes; Constitution of the nitrating fluid .... 176

Proportions of acids for explosive gun-cotton and for soluble gun-cotton or collodion-cotton; Condition of the nitrating fluid; Importance of the constancy of the composition of the acid mixture . • • . . 177

Regeneration of the nitrating fluids; Use of fuming sulphuric acid; Execution of nitration 178

Nitrating apparatus, described and illustrated. . • . . . 179

Proportion between acid and cotton; Time required for nitration; Use of a centrifugal apparatus for effecting nitration » , , , * 181

Washing the gun-cotton; Ignition of gun-cotton when introduced into the washing tank; Construction of the wash-tank ..... 183

Changes in gun-cotton ; Measures to insure the removal of the acid, and comminution of the gun-cotton for this purpose; Apparatus used . . 184

Separation of the comminuted gun-cotton from the water , , . 185

Drying the gun-cotton; Drying upon frames covered with linen; Guttmann's plan of drying gun-cotton; Mode of heating the drying room . 186

Hygroscopicity of dry gun-cotton; Mode of packing gun-cotton; Explosive gun-cotton, and mode of compressing it 187

Compression of gun-cotton for loading torpedoes; Increasing the stability of the nitro -cellulose; Manifestation of changes in the product . . 188

A. Luck and C. F. Gross's process for increasing the stability of nitrocellulose; O. E. Schulz's process for this purpose . .... 189

Soluble gun-cotton or collodion-cotton; Great importance of collodion-cotton for the preparation of threads ....... 190

Influence of the duration of the action of the acid mixture upon the cotton; Temperature to be used for nitration; Connection between the solubility of nitro-celluloses and the content of nitrogen in the products . 191

Characteristics of properly prepared collodion-cotton; Disintegration of the nitro-combination; Collodion-cotton from fine tissue-paper , . 192

Collodion; Collodion for photographic purposes; Material best adapted for the preparation of collodion ........ 193

Composition of nitro-celluloses; Cellulose hexanitrate; Cellulose tetranitrate ............. 194

Cellulose trinitrate; Cellulose dinitrate; Behavior in drying of a solution of dinitro-cellulose in ether-alcohol; Effect of an admixture of dinitro-cellulose upon collodion . ... ... ... 195

Neutralization of the collodion-cotton; Preparation of the solution; Influence of the physical condition of collodion-cotton upon its solubility; Mode of keeping collodion-solution . . . . . , .196

Elastic masses from nitro-cellulose (artificial rubber); Production of masses from nitro-cellulose possessing considerable elasticity; Fluids which may be used for this purpose 197

Mechanical manipulation of the mass; Most suitable solvent; Recovery of the volatile solvent; Further manipulation of the mass. . • . 198

Nature of the masses finally obtained; Mixing the masses with indifferent bodies; Inflammability of the masses and mode of reducing it . . 199

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Cellulose esters; Cellulose acetic ester 200

Composition of cellulose tetra-acetate, and its indifFerence towards the

action of chemicals .......... 201

Applications of cellulose acetic ester; Preparation of an acetyl derivative

of cellulose according to L. Lederer ....... 202

Cellulose butyric ester; Other similar combinations; "Solid spirit;" Mode

of bringing alcohol into a solid form ....... 203

IX. Artificial Silk

Source of natural silk; Composition of raw silk; Scouring or boiling raw

Appearance of silk under the microscope; Early efforts to produce artificial silk; Varieties of artificial silk 206

Historical development of the artificial -si Ik industry; Credit due to M. de Chardonnet; Du Vivier's and Lehner's processes; A. Millar's method; Hummel's process .......... 207

Cadoret's method; Diiference between the methods according to which textile threads are prepared from pure cellulose and from nitro-cellulose; Invention of Dr. Hermann Pauldy; Process proposed by Langhaus. 208

Cheapness and safety of the preparation of silk-like threads from viscose solution; Chardonnet artificial silk; Chardonnet's original patent for preparing textile threads 209

Details of the practical application of Chardonnet's process; Nitration of the cotton 210

Nitrating vessels; Time required for nitration ...... 211

Physical behavior of the nitrated cotton; Physical examination of the nitrated cotton; Results of Chardonnet' s comparative experiments . 212

Eemoval of acid from the cotton; Washing the nitrated cotton; Preparation of the collodion solution ........ 213

Solvent used; Time required for solution; Filtering the solution and filter for the purpose 214

Storing the solution; Spinning the collodion; Disposition of the spinning apparatus; Mode of making the glass spinners 215

Arrangement of the spinners; Reeling up the threads; Removal of the vapors of alcohol and ether from the spinning room .... 216

Chardonnet's spinning apparatus, described and illustrated . . . 217

Condensing vessels; Throwing or twisting the individual threads; Inflammability of artificial silk; Denitration ....... 219

Mode of effecting denitration; Composition of denitrating fluids; Use of ammonium sulphide for the purpose, and its preparation; Recognition of the correct composition of the denitrating fluid .... 220

Bleaching the silk; Preparation of colored artificial silk; Direct coloring of the silk while in the course of preparation; Mixture of the coloring matter with the collodion . . . . . . . • . 221

CONTENTS. XVll

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Dyeing the finished silk; Du Vivier's artificial silk .... 222

Method of nitration by means of dry saltpetre and sulphuric acid; Solvent

for the nitro-cellulose .......... 223

Lehner's artificial silk; Solvent for the nitro-cellulose; Modification of

Denitration of artificial silk; H. Richter's investigations regarding this

subject; Pith of Richter's method; Cuprous chloride for denitration . 225 Special advantage claimed for Richter's process; Recovery of the nitrogen

compounds; Recovery of the oxy-salts 226

A. Peit's method for the preparation of artificial silk; Drawbacks of the

process of producing artificial silk from nitro-cellulose; Spontaneous

ignition of nitro-cellulose ......... 227

X. Cellulose Threads (Cellulose Artificial Silk and Lustra- Cellulose)

Methods for the conversion of cellulose into a solution from which artificial textile threads may be produced; Advantages of the process; Use of cuprammonium as solvent for cellulose ..... 229

Dr. Pauly's artificial silk; Operation for the production of the thread; Purification of the cotton ......... 230

Dissolving the cotton in cuprammonium; Apparatus for the purpose . 231

Judging the progress of solution by samples ...... 232

Filtration of the solution and filter used for the purpose .... 233

Spinning the solution; Construction of the contrivance in which the formation of threads is effected; Arrangement of the spinners; Collector for the threads .......... 234

Washing the threads; Further manipulation of the threads by mechanical means; Properties of cellulose artificial silk ..... 235

E. Bronnert's process for the preparation of textile threads; Conversion of cellulose into soda-cellulose; Use of the substances according to molecular weights .......... 236

Preparation of cuprammonium; Removing the turbidity of the solution; Filtering the solution .......... 237

Conversion of cupric hydroxide into cuprammonium, and apparatus employed ............ 238

Preparation of cuprammonium solution according to the process of E. Bronnert, M. Fremery and J. Urban 239

Recovery of the copper; Various methods for this purpose . . . 240

Artificial silk according to M. Fremery and J. Urban; Manner of drying the thread ; Phases in the drying process 242

Composition of the fluid used for the decomposition of the cellulose solution; Explanation of the effect of concentrated sulphuric acid . . 243

Artificial horse hair, its production and uses ...... 244

XV 111 CONTENTS.

XL

Textile Threads prom Viscose (Threads from Lustra-Celllulose). Coagulation of viscose solution; Simplicity of the process of obtaining pure cellulose from viscose; Experiments in making textile threads from viscose. ............ 246

Properties of viscose threads; Cost of producing threads from viscose . 247 Preparation of perfectly clear viscose solution, and apparatus employed . 248 Filtering the solution, and filter used; Spinning apparatus . . . 249 Treatment of the threads emerging from the spinning apparatus . . 250 Importance of using viscose solution of the same temperature . . . 251 Kegulation of heat; Preparation of textile threads according to Stearn.; Preparation of long, narrow strips for taking pictures for the cinematograph 252

Millai-'s artificial silk (gelatine silk) . . . . . . .253

Deprivinggelatine threads of their brittleness; General properties of textile threads produced by artificial means; Lustre of artificial silk; Effect of

water on artificial threads 254

Facts to be taken into consideration in dyeing threads of artificial silk; Microscopical examination of artificial textile threads; Difference between natural and artificial silks ........ 255

Table showing diameters of various kinds of silks; Optical phenomena exhibited by natural and artificial silks; Tenacity of artificial silk as compared with natural silk 256

Dr. Hassack's investigations; Moisture and hygroscopic! ty of artificial

silks; Specific gravity of artificial silks 257

Elasticity and tenacity of artificial silk; Eesults of tests .... 258 Behavior of artificial silk in a chemical respect; Principal difference between the various kinds of artificial silk 259

Microscopical examination of artificial silk with the use of reagents. . 260 Distinction between cellulose and nitro-cellulose silks .... 261

XII. Celluloid

Invention of celluloid by Hyatt, of Newark, N. J. ; Properties of celluloid; Nature of celluloid 263

Methods for the preparation of celluloid; Value of the separate methods . 264 Classification of the methods used for the manufacture of celluloid; Preparation of the collodion-cotton 265

Material used according to the original statements by Hyatt; Preparation

of celluloid according to Hyatt 266

Preparation of celluloid according to Tribouillet and Besancele . . 268 Preparation of celluloid with alcoholic camphor solution .... 269

Preparation of celluloid according to Magnus 270

Mode of preparing the solution of dry collodion-cotton; Preparation of

CONTENTS. XIX

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celluloid with recovery of the solvent; Description of a process which can be practically applied ......... 271

Manner of testing freshly-prepared collodion-cotton; Requisites of collodion-cotton which is to be dissolved ....... 272

Drying the collodion-cotton; Apparatus in which the solution of collodion-cotton and camphor is effected, and manner of working with it; Solvent to be used .......... 273

Advantages of anhydrous ether as a solvent; Recovery of the ether evaporating from the fluid celluloid mass ...... 274

Apparatus for preparing the solution ; Trays for solidifying the solution, described and illustrated ......... 275

Apparatus for condensing the ether-vapors, described and illustrated . 276 Removing the finished celluloid from the trays ..... 278

Drying chamber; Heating celluloid to be rolled ..... 279

Properties of celluloid; Nature of celluloid at the ordinary temperature . 280 Mode of rendering celluloid plastic by heating; Spontaneous decomposition of celluloid; Inflammability of celluloid. ..... 281

Behavior of celluloid towards solvents; Physical properties of celluloid;

Example of the great tenacity and elasticity of celluloid . . . 282 Working celluloid; Mechanical manipulation of celluloid; Rolling celluloid 283

•Coloring celluloid; Employment of tar colors for this purpose; Coloring transparent celluloid articles; Production of articles from the colored material ............ 284

Production of certain color effects; Red and scarlet ..... 285

Blue; Indigo-blue; Berlin-blue; Violet; Brown; Gray; Black . . . 286 Printing on celluloid; Preparation of a celluloid-plate for printing; Process for providing celluloid articles with colored pictures . . . 287 Transferring pictures to celluloid; Mode of protecting the pictures . . 288 Printing on celluloid in the same manner as pictures, in many colors, are produced on paper; Preparation of gutta-percha printing blocks; Celluloid with filling masses. ......... 289