Wood and other organic structural materials

WOOD

AND OTHER

ORGANIC STRUCTURAL
MATERIALS

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WOOD

AND OTHER

ORGANIC STRUCTURAL
MATERIALS

BY
CHARLES HENRY SNOW, C. E., Sc. D.

DEAN OF THE SCHOOL OF APPLIED SCIENCE, NEW YORK UNIVERSITY
MEMBER OF THE AMERICAN SOCIETY OF CIVIL ENGINEERS, ETC.

FIRST EDITION

McGRAW-HILL BOOK COMPANY, INC.

239 WEST 39TH STREET. NEW YORK

LONDON: HILL PUBLISHING CO., LTD.

6 & 8 BOUVERIE ST., E. C.
1917

A<\

COPYRIGHT, 1917, BY THE
MCGRAW-HILL BOOK COMPANY, INC.

» f f

f - ' . *> * *" \

THE MAPLE PRESS YORK PA

PREFACE

The purpose of this book is to present general as well as phys-
ical characteristics of a group of structural materials, most of
which are of organic origin. Among the materials thus described
are woods, paints and varnishes — with their associated oils, pig-
ments, gums, and resins — glues, creosotes, and indiarubber. As
stated, most of these materials are of organic origin. Those that
are not, such as pigments and creosotes, have been added because
of their close practical association with the others.

The book is designed for engineers, architects, students in
schools of technology, teachers of manual training and others
who use the materials described or who are interested in their
properties.

A statement of the reasons for separating structural materials
along the line of organic and inorganic origin, seems to be in
order. First, this basis is convenient: in fact, so many of the
important organic materials are used in connection with one
another that most of the present book might easily appear under
such a title as "Properties of Woods and Associated Materials
of Construction"; and, in the same way, the principal inorganic
materials, steel, stone and concrete, are commonly associated.
Second, the basis suggested is logical: organic materials are
fundamentally different from inorganic materials, for the former
are results of physiological processes and have within them the
influence of life; these materials may manifest variations and
special traits which do not appear in the more homogeneous and
constant materials of the inorganic group. Assuming that some
form of classification is desirable, where subject matter is as ex-
tensive as that within the present field, the writer ventures to
urge the merits of the one now employed. Also, a book devoted
especially to the materials here considered seems warranted. It
is true that the inorganic materials, metals, stones, and concrete,
upon which principal attention is so often bestowed in text-books,
do predominate in the larger engineering structures; but it is
equally true that the organic material wood predominates in
other structures, and that some of the materials now considered

v

365844

vi PREFACE

are used in practically all structures with which the engineer has
to do.

The opportunity is taken to criticise the degree of emphasis
often laid in text-books upon those properties of structural mate-
rials which relate to strength. That this phase of the subject
should be given precedence is beyond all question, but that it
should ever be emphasized so greatly as to diminish or more or
less replace attention which might otherwise be given to other
features, such as durability, is questioned. In other words, it is
regarded as pedagogically unfortunate when the whole story can-
not be at least outlined to the student, when one part is detailed
to such an extent that the other parts cannot be detailed at all.
The belief is expressed that many students in schools of tech-
nology do not realize as early as they should, how real, live, and
practical the subject " Properties of Structural Materials" is, and
how greatly knowledge of it will influence works which they may
later design and construct, and that one cause for this, in the case
of some students, is the slight or omission here referred to.

The printed sources of information employed are acknowledged
in footnotes throughout the text, and in a bibliography arranged
for those who wish further information on any of the parts in
question. In addition to these printed sources of information,
the writer is deeply indebted to some who have assisted him with
special information and with criticisms and now acknowledges
assistance thus received from Professors W. Kendrick Hatt,
Hermann von Schrenk, C. Stuart Gager, Charles P. Sigerfoos,
Edgar W. Olive, Alvah H. Sabin, the late Charles E. Bessey, and
the late Mr. Octave Chanute, past president of the American
Society of Civil Engineers. He also thanks, among others, Mr.
C. D. Mell, Acting Dendrologist of the United States Forest
Service, Mr. Charles A. Hexamer of the National Board of Fire
Underwriters, Mr. Norman Taylor of the Brooklyn Botanic Gar-
den, Mr. Edward A. Hewitt, late chemist of the Cooper Glue
Company, Dr. Lothar E. Weber, of the Boston Indiarubber Labo-
ratory, and several of his colleagues in New York University.

CHABLES H. SNOW.

UNIVERSITY HEIGHTS, BRONX,

NEW YORK CITY,

June 1, 1917.

TABLE OF CONTENTS

PAGE
PREFACE v

INTRODUCTION

Practical Value of Subject "Properties of Materials." Materials
Divided into Organic Materials and Inorganic Materials; Basis for
this Division. Conservation. Relation of Organic Materials
to Conservation xvii

CHAPTER I

WOODS COMPARED WITH STONES AND METALS. NOMENCLATURE.
FUNDAMENTAL CLASSIFICATIONS

Comparisons. Consumption of Wood. Reasons for Preferring Wood.
Uses of Wood. Common and Botanical Names. Classifications:
Botanical Classification of Trees and Woods; Gymnosperms (Coni-
ferse) and Angiosperms (Monocotyledons, Dicotyledons) ; Practical
Classification of Trees and Woods; Banded Trunks and Woods
(Coniferous Series, Broadleaf Series); Non-Banded Trunks and
Woods . 1

CHAPTER II

TREES. PHYSIOLOGY OF TREES. VALUE OF FORESTS. FORESTRY

Trees Considered as Sources from which Woods are Derived. Physi-
ology of Trees: The Root System; The Leaves; The Trunk (Length-
Growth, Thickness-Growth, The Cambium, Sap Movement, In-
fluence of Sunlight). Value of Forests (Humus, -Influence of
Forests on Streamflow, Influence of Forests on Erosion). For-
estry

vii

viii TABLE OF CONTENTS

CHAPTER III

PAGE

WOODS. CHARACTER AND ARRANGEMENT OF WOOD-ELEMENTS. IN-
FLUENCE OF CELLULAR STRUCTURE UPON CHEMICAL
COMPOSITION AND PHYSICAL PROPERTIES OF WOODS.
IDENTIFICATIONS. STATEMENT OF WEIGHTS
AND MODULI EMPLOYED IN TABULAR
DESCRIPTIONS OF SPECIES

Definitions. Cellular Structure of Wood. Importance of Subject.
Wood-Elements: General; Wood-Fibers; Tracheids; Vessels; Wood-
Parenchyma Fibers; Pith-Rays (Forms, Functions); Resin-Canals
(Resins) ; Arrangement of Wood-Elements; Associated Compounds;
Influence of Cellular Structure upon Chemical and Physical
Properties of Woods. Identifications. Statement of Weights and
Moduli Employed in Tabular Descriptions of Species 17

CHAPTER IV

BANDED TRUNKS AND WOODS. GENERAL.
(Conifers and Dicotyledons)

General. Parts of the Trunk: Wood-Elements; Annual Layers (Spring
and Summer Deposits, Means of Determining Age, Means of
Identification); Bark (Inner Bark, Living Bark, Corky Layer,
Epidermis): Sapwood; Heartwood; Pith. Development (Cross,
Radial, and Tangential Surfaces, Grain or Figure, Definitions).
Defects (Shakes, Checks, Knots, Disease, Manufacturers' Stand-
ards). Sub-Divisions: Coniferous, Needleleaf or Softwood Series;
Non-Coniferous, Broadleaf or Hardwood Series . . . 34

CHAPTER V

BANDED TRUNKS AND WOODS (Continued)
Coniferous or Needleleaf Series (Conifers)

General and Introductory. Pine: The Soft Pines and Hard Pines
(White Pine, Sugar Pine, Georgia Pine, Cuban Pine, Shortleaf
Pine, Loblolly Pine, Bull Pine, Norway Pine, Pitch Pine, Northern
Pine, etc., etc.). Kauri Pine (Kauri Pine). Spruce (Black Spruce,
White Spruce, Sitka Spruce, etc.). Douglas Spruce (Douglas
Spruce). Fir (Balsam Fir, Great Silver Fir, Red Fir, White Fir,
Noble Fir). Hemlock, (Hemlock Western Hemlock). Larch or
Tamarack (Larch). Cedar (Red Cedar, Juniper, White Cedar,
Canoe Cedar, Port Orford Cedar, Yellow Cedar, Incense Cedar,
etc.). Cypress (Bald Cypress). Redwood (Redwood, Giant
Redwood) . 44

TABLE OF CONTENTS ix

CHAPTER VI

BANDED TRUNKS AND WOODS (Continued)

Broadleaf Series, Part One (Dicotyledons)

PAGE

General, Definitions. Oak (White Oak, Cow Oak, Chestnut Oak,
Post Oak, Bur Oak, Western White Oak, Red Oak, Pin Oak,
Spanish Oak, Black Oak, Live Oak, California Live Oak, English
Oak, etc.). Ash (White Ash, Red Ash, Blue Ash, Black Ash,
Green Ash, Oregon Ash, etc.). Elm (White Elm, Cork Elm, Slip-
pery Elm, Wing Elm, etc.). Maple (Sugar Maple, Silver Maple,
Red Maple, Oregon Maple, Box-elder, etc.). Walnut (Circassian
Walnut, Black Walnut, White Walnut, etc.). Hickory (Shagbark
Hickory, Pignut, Mocker Nut, Pecan, etc.). Chestnut, Chinqua-
pin (Chestnut, Chinquapin, etc.). Beech, Iron wood (Beech, Iron-
wood, Hop Hornbeam, etc.). Sycamore (Sycamore, California
Sycamore, etc.). Birch (White Birch, Paper Birch, Red Birch,
Yellow Birch, Sweet Birch, etc.). Locust, Mesquite (Black
Locust, Honey Locust, Mesquite, etc.) 102

CHAPTER VII

BANDED TRUNKS AND WOODS (Continued)
Broadleaf Series, Part Two (Dicotyledons)

White wood Group (Tulip Tree, Poplar, Cottonwood, Black Cotton-
wood, Cucumber-tree, Basswood, etc.); Willow (Black Willow,
White Willow, etc.); Catalpa (Hardy Catalpa, Catalpa, etc.);
Mulberry (Red Mulberry, etc.); Horse Chestnut. Buckeye
(Ohio Buckeye, Sweet Buckeye, etc.); Gum (Sweet Gum, Tupelo
Gum, Sour Gum); Holly. Boxwood. Lignumvitse (Holly, Dog-
wood, Lignumvitse, etc.); Laurel (California Laurel, Madrona,
etc.); Sassafras. Camphor (Sassafras); Greenheart (Greenheart) ;
Persimmon. Ebony (Persimmon) ; Osage Orange. Cherry (Osage
Orange, Wild Black Cherry) ; Mahogany (Mahogany, Spanish
Cedar, White Mahogany); Satinwood; Teak (Teak); Some Tropical
Species (Sabicu, Sissoo, Rubber Tree, California Pepper, China-
berry, Rosewood, Sandalwood) ; Eucalyptus (Blue Gum, Red Gum,
Jarrah, Karri, Tuart, Sugar Gum, Giant Eucalypt, Manna Gum,
Stringybark, Red Mahogany, etc.) 169

CHAPTER VIII

NON-BANDED TRUNKS AND WOODS
(Monocotyledons)

General and Introductory. Parts of the Trunk. Wood-Elements.
Uses. Sub-Divisions. Palm (Washington Palm, Date Palm,
Cabbage Palmetto, etc.); Yucca (Joshua-tree); Bamboo (Bamboo,
etc.) .224

TABLE OF CONTENTS

CHAPTER IX

PAGE

SPECIAL PROPERTIES OF WOODS DUE TO THEIR ORGANIC ORIGIN. CHEMICAL

COMPOSITION OF WOODS. PHYSICAL PROPERTIES OF WOODS:

DESCRIPTIONS OF WEIGHTS AND MODULI EMPLOYED.

MOISTURE IN WOODS; INFLUENCE OF MOISTURE,

ANTISEPTICS, AND HEAT UPON THE

PHYSICAL PROPERTIES OF WOODS

General and Introductory. Special Properties due to Organic Origin.
Chemical Composition: Chemical Elements; Organic Compounds
(Cellulose, Lignin, Associated Materials); Inorganic Compounds.
Physical Properties: Descriptions of Physical Properties; Strength,
Rigidity, Elasticity, Resilience, Hardness, Ability to Hold Fasten-
ings, Weight, Specific Gravity and Density, Porosity, Conduc-
tivity, Resonance. Measurements of Physical Properties (Diffi-
culties, Selection and Preparation of Test-Pieces, Sizes of Test-
Pieces, Standards for Moisture, Woods Compared with Stones and
Metals, Existing Experiments Separated into Groups). Descrip-
tions of Weights and Moduli Employed. Influence of 'Moisture,
Antiseptics, and Heat upon Physical Properties : Moisture in Wood
(Quantity of Moisture, Distribution of Moisture, Influence of
Moisture upon Decay, Influence of Moisture upon Physical Prop-
erties, Influence of Moisture upon Distortion). Influence of Anti-
septics upon Physical Properties. Influence of Heat upon Physical
Properties . . 233

CHAPTER X

FAILURE OF WOOD BECAUSE OF USE, EXPOSURE, AGE, AND DECAY

General and Introductory. Failure of Wood because of Use. Failure
of Wood because of Exposure. Failure of Wood because of Age.
Fungous Diseases: Fungi (Descriptions, Conditions under which
Fungi Act); Fungous Diseases of Trees (Diseases of Foliage, Dis-
eases of Roots, Diseases of Trunks) ; Fungous Diseases of Structural
Woods (Life of Fungi Influenced by Position or Exposure of Wood,
First Exposure, Second Exposure, Third Exposure, Influence of
Top-Soil, etc., Fourth Exposure, Evidence of Disease, Methods of
Treatment, Methods of Protection) 267

TABLE OF CONTENTS xi

CHAPTER XI

• FAILURE OF WOOD BECAUSE OF FIRE. WOOD AS AN AGENT IN
CONFLAGRATIONS. FIRE PROTECTION

PAGE

General and Introductory. Fire Losses in the United States. Com-
parison of Losses with those in Other Countries. A Principal
Cause for Excessive Fire Losses in the United States. Wood as an
Agent in Conflagrations: The Burning of Wood; Attempts to Pre-
vent Wood from Burning; Internal Protection (Fire-Retarding
Materials, Processes for Introducing Fire-Retarding Materials
within Woods, Preparation of Woods to Receive Fire-Retarding
Materials) ; External Protection (Materials, Fireproof Paints,
Metals, etc., Methods used to Apply Materials, Preparation of
Woods to Receive Materials); Methods of Testing "Protected"
Woods; Methods used to Extinguish Burning Woods; Materials
(Water, Carbon Dioxide, Carbon Tetrachloride, etc.); Devices for
Applying Materials (Fire Engines, Chemical Engines, Extin-
guishers) ; Organizations. Some Principles of Fire Protection : His-
torical and Introductory; Burning Buildings (Inside Fires, Outside
Fires, Temperatures in Burning Buildings); Methods by which
Buildings are Prevented from Burning; Materials (Metals, Natural
Stones, Artificial Stones, Combinations); Influence of Design,
Special Devices, etc. (Fireproof Construction, Roofs, Door Open-
ings, Fire-Doors, Window Openings, Fire-Shutters, Wired-Glass,
Automatic Sprinklers, Signals) ; Care or Maintenance of Structures
(Inflammable Stores, Watchmen's Recorders) 277

CHAPTER XII

FAILURE OF WOOD BECAUSE OF ANIMAL LIFE. MARINE AND TER-
RESTRIAL WOODBORERS. METHODS OF PROTECTION

Introductory. Marine Woodborers: The Shipworm; Form, Physiology,
Reproduction, and Development, Influence of Temperature and
Water, Method of Attack, Size of Borings, Rapidity of Work,
Field of Attack, Woods Subject to Attack: The Limnoria; Form
and Physiology, Influence of Temperature and Water, Method of
Attack, Character of Excavation, Size of Borings, Rapidity of
Work, Field of Attack, Woods Subject to Attack: The Chelura;
Form and Physiology, Method of Attack, Character of Excavation,
Size of Borings, Field of Attack : Miscellaneous ; Fresh Water
Borers, Stone Borers, Barnacles. Methods of Protection: Removal
during the Breeding Season; Change of Water; Use of Selected
Woods; External Coatings (Bark, Planks, Metals, Teredo Nails,
Paraffin, Tar, Paints, Reinforced Coatings, Cement, Sand, Natural
Protection); Preservatives Applied within Woods (Creosotes);
Substitution. Terrestrial Woodborers: General; Beetles (Char-
acteristics, Summary); Moths and Butterflies (Characteristics,
Summary); Termites or White Ants (Characteristics, Protection,
Summary); Black Carpenter Ant; Carpenter Bee. Methods of
Protection .

xii TABLE OF CONTENTS

CHAPTER XIII

PROTECTIVE METHODS — SEASONING

PAGE

General and Introductory. Natural Seasoning. Water Seasoning.
Kiln Seasoning (General, Influence of Temperature, Influence of
Moisture, Air-currents, Forms of Kilns, Operation of Kilns, Diffi-
culties, Time Required). Protection of Seasoned Woods .... 326

CHAPTER XIV

PROTECTIVE METHODS — INTERNAL TREATMENT. PRESERVA-
TIVE COMPOUNDS APPLIED WITHIN WOODS

General and Introductory. Materials: Tannin; Copper Sulphate;
Mercury Bichloride; Zinc Chloride; Creosote (General, Definitions,
Specifications, Analyses, Required Quantities, Distribution, etc.);
Miscellaneous Materials (Carbolineum). Processes Used to Intro-
duce Antiseptics within Woods; Superficial Processes (Dipping,
Soaking, Brush Applications); Non-Pressure Processes (The Kyan
and Open-Tank Processes); Pressure Processes (Use of Cylinders,
Pressure, Heat and Vacuum, Full Cell, Empty Cell, Bethell, Hay-
ford, Burnett, Rutgers, Card, Allardyce, Rueping, Lowry, Boiling,
Wellhouse, Creo-Resinate, Creoair, Boucherie, Charring, Vulcan-
izing, Robbins, Seeley, Powell, Thilmany, Hasselmann, and Ferrell
Processes) ; Woods that are to Receive Treatment 335

CHAPTER XV

PROTECTIVE METHODS — EXTERNAL TREATMENT. OILS, PAINTS,

VARNISHES, AND OTHER COATINGS. THEIR APPLICATION TO

SURFACES OF WOODS

General and Introductory. Materials: Oils (Solidifying or Drying Oils
and Driers, Non-Solidifying Oils, Volatile Oils and Spirits); Pig-
ments and Fillers (White Lead, Zinc White, Barium Sulphate, Red
Lead, Iron Oxides, Carbon Paints, Fillers); Gums, Resins, and
Varnishes (Amber, Copal, Anime, Zanzibar, Kauri, Shellac, Sanda-
rach, Dammar, Mastic, Rosin, Varnishes); Miscellaneous Mate-
rials (Stains, Whitewash, Kalsomine, Cold Water Paints, etc.).
Methods of Application: The Application of Paint; Influence of
Application upon Durability; The Application of Varnish (Plain
Varnished Surfaces, Polished Surfaces, Varnish Paint or Enamelled
Surfaces). Preparation of Woods to Receive Paints and Var-
nishes. Other Coatings (Metals, etc., etc.) 377

TABLE OF CONTENTS xiii

CHAPTER, XVI

ADHESIVES. CATTLE GLUES. FISH GLUES. SELECTION, TESTING -
AND APPLICATION OF GLUES

PAGE

General and Introductory. Cattle Glues: Sources; Manufacture;
Properties (Foreign and Domestic Glues, Influence of Heat and
Moisture, etc.); Selection; Application (Dissolving the Glue, Pre-
paring the Wood, Completing the Joint); Protection of Joints
(Resistance to Heat, Resistance to Moisture, Influence of Forma-
lin); Durability of Joints. Fish Glues: Sources; Manufacture;
Properties; Selection; Application. Methods of Testing Glues:
Cattle Glues (Standards, Samples, Appearance, Fracture, Odor,
Acidity, Grease, Viscosity, Foam, Strength); Fish Glues. Some
Uses: Veneers (Reasons for Preferring Veneered Work, Prepara-
tion and Uses of Veneered Work) ...;....,...... 403

CHAPTER XVII

INDIARUBBER AS A STRUCTURAL AND MACHINE MATERIAL. SOURCES,
PREPARATION, PROPERTIES, AND USES OF INDIARUBBER

General and Introductory. Indiarubber. Rubber Latex; Collection
of Latex, Rubber obtained from Latex. Geographical and Botan-
ical Classifications of Rubber; Crude and Refined Rubber, Fresh
and Reclaimed Rubber, Wild and Plantation Rubber. Purification
and Preparation of Rubber. Vulcanization. Properties of Pure
Rubber and Vulcanized Rubber. Synthetic Rubber. Uses of
Rubber 421

BIBLIOGRAPHY 437

INDEX. . 447

LIST OF PLATES

FACING
PLATE PAGE

I Arrangement of Wood Elements — Cross Sections 18

II Arrangement of Wood Elements — Tangential Sections .... 22

III Arrangement of Wood Elements — Radial Sections ..... 28

IV Influence of Wind upon Trees at Timber Line ....... 42

V Fungous Diseases of Wood 268

VI Portion of Floor Beam after Attack by Dry Rot Fungus . . . 274

VII Appearance of Fire Doors after Fire ; . 286

VIII Details of Tin Clad Fire Door. . ", . . . . . . 296

IX Work of the Shipworm ... . . . . , . . . . . % 302

X Work of Shipworm — Large Borings ' . ,' 308

XI Work of the Limnoria . . . ... ............ 312

XII Work of the Chelura. 314

XIII Work of Larvae of Beetles. "Bookworms". ........ 318

XIV Work of Large Carpenter Ant. . . . ." ..... . . ... 322

XV High Power Spraying Apparatus in Action 324

XVI Trough Employed in Kyan Process 354

XVII Open Tank Process Applied to Butt Treatment of Poles . . . 358

XVIII Steel Cylinders Designed for Treating Wood 362

XIX Plant for Creosoting Lumber 370

XX Application of Glue in Large Curved Joint 416

xv

INTRODUCTION

A knowledge of the properties of the substances used in con-
struction gives confidence to those who employ them and permits
smaller margins beyond calculated requirements than otherwise
would be possible.

Wood is one of the primary materials of construction. The
others are stone and iron. These fundamental materials possess
distinguishing properties, and each as a class includes a series of
individuals or varieties, which are again distinguishable from one
another by certain minor or specific properties.

All structural materials may be divided as they are organic and
inorganic. Wood and other organic structural materials are
characterized by qualities due to life processes, age, and other
physiological causes. Stone, iron, and other inorganic materials
are not distinguished in this way; these materials are more
simple, homogeneous, and constant.

What is now known as " conservation " has been defined1 as
"the greatest good to the greatest number — and that for the
longest time." The idea of conservation includes the reduction
of waste. The future as well as the present is regarded. The
broader needs of the nation are placed before the immediate
needs of the individual; and, whenever possible, resources are
considered more as they produce yearly incomes and less as
though they were fixed sums to be drawn upon directly and thus
exhausted ultimately.

Woods and other organic materials respond more completely
than metals and stones to the application of the principles of con-
servation because they can be reproduced. The development of
a forest requires time, but such development is possible, and once
established the forest can be maintained so as to yield for in"
definite periods. On the other hand, inorganic materials exist
in fixed and final quantities. The more the materials of the

1 Van Hise in "The Conservation of Natural Resources in the United
States." See also "The Fight for Conservation," Pinchot; "Conservation
of Water by Storage," Swain (Yale University Press); etc., etc.

xvii

xviii INTRODUCTION

inorganic group are used, the more quickly they will become
exhausted, and once exhausted these materials cannot be
reproduced.

Wood is the principal organic structural material but it is not
the only one. The oils that are used in paints, varnish-resins,
glues, indiarubber and other materials are of this series.

WOOD

AND OTHER

ORGANIC STRUCTURAL
MATERIALS

CHAPTER I

WOODS COMPARED WITH STONES AND METALS. COMMON AND
BOTANICAL NAMES. FUNDAMENTAL CLASSIFICATIONS

Information relating to the general properties of wood compares
in importance with information relating to the general properties
of steel, stone, and cement. Engineers use more wood than any
other set of men, yet general facts about wood, aside from those
relating to its strength, are often relegated to the consideration
of the botanist or the forester.

The consumption of wood has never decreased, although metals
and stones have been substituted for it in many positions. In
England, the consumption per capita more than doubled in the
fifty years preceding 1895, in spite of the fact that nearly all of
the wood used in that country had to be imported. In 1905,
the total yearly mill value of wood products in the United States
was over nine times as great as the combined product of gold and
silver, and twice as great as the value of the wheat crops.1

The importance of wood as a material of construction is well
expressed in the quotation that follows :2

"Wood is an indispensable part of the material structure upon which
civilization rests; and it is to be remembered always that the immense
increase of the use of iron and substitutes for wood in many structures,

1 A conservative estimate places the yearly mill value of wood products
in the United States alone at $1, 100,000.000. The spring and winter wheat
crops of 1905 were together valued at $518,372,727. The production of
gold and silver during the year 1904 was valued at $112,871,026. See also
"Forest Resources of the World," Zon (United States Forest Service
Bulletin, No. 83).

2 Credited to the Honorable Theodore Roosevelt.

1

2 ORGANIC STRUCTURAL MATERIALS

while it has meant a relative decrease in the amount of wood used, has
been accompanied by an absolute increase in the amount of wood used.
More wood is used than ever before in our history."

Wood is preferred because it is easily worked and light in
weight. In many positions, it is as durable as iron. When dry
it is a poor conductor of heat and electricity and is stronger than
is commonly supposed. The tensile strength of a bar of hickory
may exceed the tensile strength of a similar bar of wrought iron
of the same length and weight.1 However, wood is not homo-
geneous like metal and most of the stones that are used for build-
ing, but is so variable that several parts of the same tree often
exhibit widely different qualities.

Most wood is used in construction; that is, in mines, railways,
houses, and ships where size or quantity is required and where
finish and appearance are less important. Much wood is used in
cabinet work and in positions where appearance, appropriateness,
and finish are important. Such woods are more in evidence, but
the amounts used are actually very much smaller than the amounts
used in construction. Some wood is required for turnery, carv-
ings, and implements that demand exact qualities that can be
secured in small pieces only. Some wood is used indirectly, and
in the manufacture of paper-pulp, gunpowder, and chemicals.
There are also by-products of trees, such as tanbark, turpentine,
resin, and sugar.

Common and Botanical Names. — Woods appear to be more
numerous than they actually are, because more than one name is
so often applied to the same species. Supplies are often brought
from far distant places when woods of the same kind are available
nearby, but are not recognized because they are called by differ-
ent names. One species, the Southern, Yellow, Georgia, or
Longleaf Pine (Pinus palustris), has nearly thirty local names.
Such confusion can be avoided only by regarding the recognized
botanical nomenclature.

Not only is it true that several names are often applied to the
same wood, but, strange as it may seem, a fairly constant single
product is sometimes derived from several unrelated species.
The single name cedar is thus applied to several species of durable
characteristically scented woods, which have similar anatomical
features and which are derived from species that are not closely
related to one another.

1 United States Department of Agriculture, Yearbook, 1896, p. 392, Roth.

NOMENCLA TURE—CLASSIFICA TIONS 3

The botanical name of a plant is made up of terms denoting
genus and species. For example, Quercus is the generic name
that includes all the species of oak, while alba and rubra are
specific names that apply to two particular species of the genus
Oak. Quercus alba and Quercus rubra are completed names.
The names of species are not fixed, but differ with authorities
so that it is often best to add the abbreviated name of the
botanist responsible for the name employed. Illustrations
would be Quercus alba Linn., Quercus rubra Linn., and Ulmus
fulva Michx.

A genus may be defined as a collection of related species, and a
species may be regarded as a collection of individuals that might
easily have sprung from some single stem. Genera are grouped
into families, and both genera and families differ with authorities.
The term " variety" is applied to individuals that differ less from
one another than do species. Quercus robur var. pedunculata
indicates a variety (var. pedunculata) of a certain species (robur)
of Oak (Quercus). It should be noted that the variety of one
botanical authority is sometimes regarded as a distinct species
by another botanical authority.

About five hundred species of trees grow in the United States1
and many other species grow in other countries, yet, the great
mass of wood that is used in construction comes from compara-
tively few of these species. Sudworth excludes all but one
hundred sources in his "Trees of the United States Important
to Forestry," while a United States Treasury Department Sum-
mary contains the statement that but sixteen (16) kinds of hard-
wood were quoted in the Chicago markets on the first day of
September of the year 1900.2

The statement is also made in the source referred to, that the prin-
cipal timbers of commerce in the United States are the genera known
popularly as pine, fir, oak, hickory, hemlock, ash, poplar, maple, cypress,
spruce, cedar and walnut.

Conditions are changing. The original forests are much smaller
than in former years. Many woods that were once common are
now scarce, while other woods that were once unfamiliar are
now employed.

1 Fernow credits four hundred and ninety-five species to the United
States (Introduction to United States Forestry Bulletin No. 17); Sargent,
counting species only and excluding varieties, notes four hundred and
twenty-two species (Silva of North America).

2 1900, p. 1081.

4 ORGANIC STRUCTURAL MATERIALS

Botanical Classification of Trees and Their Woods. — Botanists
group trees as they do other seed-bearing plants, mainly upon
the characteristics of parts other than the trunks. In such groups,
the flowers, fruit, and leaves are fundamentally important. A
general classification is as follows :

I. GYMNOSPERMS. — The seeds are naked, that is, they are not enclosed
in fruit. There are three natural groups or families as follows:

(a) Cycadacece. — Practically confined to tropical and sub-tropical
regions. Practically valueless for wood. To be here disregarded.

(&) Gnetacece. — Consists of undershrubs, shrubs, and small trees, most
of which grow in the tropics. Practically valueless for wood. To be
here disregarded.

(c) Coniferce. — This is by far the largest and most important of the
three families, and the only one that yields merchantable lumber. The
Pines, Spruces, Firs, and Cedars are among the members of this family.
The seeds are borne on series of overlapping scales, arranged in what
are known as cones. The leaves of ordinary species are narrow, rigid,
needle-like, or scale-like. Resins are present. The trees are sometimes
called Needle-leaf, Softwood, and Evergreen trees, as well as Coniferous
and Cone-bearing trees.

II. ANGIOSPERMS. — The seeds are always enclosed in more or less obvi-
ous seed-vessels or fruit. These plants greatly exceed those in the pre-
ceding groups in the number of their species and in the variety of their
habits. All ordinary flowering plants are Angiosperms. There are two
classes, which, while they agree in having enclosed seeds, differ in other
matters, and in none more than in the structure of their stems or trunks.
The Angiosperms are sub-divided as follows:

(a) Monocotyledons. — These plants have one seed leaf or cotyledon,
whence the name, Mono-cotyledon. The veins in the leaves are more
or less parallel to one another. Some twenty-five thousand species are
recognized, but very few of these species yield woods that are valued
in construction. The few Monocotyledons that yield woods that are
valued in construction are associated with the tropics. The Palms and
Bamboos are Monocotyledons.

(6) Dicotyledons. — These plants have two seed-leaves or cotyledons,
whence the name ZH-cotyledon . The veins in the leaves of the Dicotyle-
dons are netted. The stems of these plants increase by layers of new
material that form, each one upon the outside of others that were formed
before. Coniferous trees increase in practically the same manner. Sev-
eral hundreds of the over one hundred thousand Dicotyledons are trees,
and these Dicotyledonous trees yield the so-called Broadleaf woods,
Deciduous woods, or Hardwoods of commerce. The Oaks, Maples, and
Hickories are among the Dicotyledons.

NOMENCLA TURE—CLASSIF1 CA TIONS 5

The woods that are valued in construction are derived from the
Conifers, the Dicotyledons, and the Monocotyledons, in the order
named. The other divisions of plant life do not produce mer-
chantable woods and may be disregarded in this connection.

Practical Classification of Trees and Their Woods. — Those
who use woods are less concerned with the flowers, fruit, and
leaves of the trees, than with the trunks, and the charac-
teristics of the woods themselves. The present text has for its
object a study of woods, as distinct from trees, and for this
reason, the features of flowers, fruit, and leaves, which are so
important to the botanist, will be regarded as secondary, and
woods will be classified upon the basis of their own properties.

From this viewpoint all trees, trunks, and woods will be divided
primarily according to the way in which new material is added to
their sections. Two great divisions will be distinguished:

1. Banded Trunks and Woods. — In this case the wood is
arranged in concentric bands or layers which, in cross-sections,
appear as rings. The trees that yield banded woods are all

FIG. 1. — Section through a banded trunk (longleaf pine, Pinus paliLstris}.

"outside-growers;" that is, new material is deposited in layers,
each one of which is formed upon the outside of other layers that
were formed before. Pines, oaks, and practically all other trees
that yield woods that are valued in construction are included in
this division. It is the group to which the name Exogen, or
Outside-grower, has been applied by the engineer.

6

ORGANIC STRUCTURAL MATERIALS

The names Exogen and Endogen are undesirable because engineers and
botanists seldom employ them in the same way. Some botanists use the
name Endogen in connection with Monocotyledonous trees and woods, but
restrict the use of Exogen to Dicotyledonous trees and woods, while others
do not employ these terms at all.

This group is divided into Conifers and Dicotyledons. The
first sub-series includes the so-called Softwoods. Coniferous,
Softwood, Needleleaf and Evergreen woods are the same. It
should be noted that in spite of the use of the word Softwood
some of the individuals of this sub-series are actually very hard.
The Dicotyledons are often referred to as Hardwoods although
some of them are really quite soft. Dicotyledonous, Hardwood,
Non-coniferous, and Deciduous woods are the same.

2. Non-banded Trunks and Woods. — These woods are not
arranged in concentric rings or layers. On the contrary, the

FIG. 2. — Section through a non-banded trunk (royal palm, Oreodoxa regid).

NOMENCLA T URE—CLASSIFICA TIONS 7

wood is scattered irregularly in small fibrous groups throughout
the tree which is, therefore, known as an " inside-grower."

The Palms, Bamboos, and a few other plants of this group
that yield useful woods are associated with the tropics. The
woods are seldom used much in construction far from the places
in which they grow. This group includes the Monocotyledons
of the botanist and is the one to which the name Endogen, or
Inside-grower, has been applied by engineers.1

1 See first paragraph page 6.

CHAPTER II

TREES. PHYSIOLOGY OF TREES. VALUE OF FORESTS.

FORESTRY

A study of iron begins at the furnace; a knowledge of stone
must include some facts with regard to the quarry from which the
stone was taken; in the same way a study of wood must commence

with a study of the tree within which
the wood was formed.

PHYSIOLOGY OF TREES.— A tree
has been defined (Century Dictionary)
as "a perennial plant which grows
from the ground with a single, perma-
nent, woody, self-supporting trunk or
stem, ordinarily attaining a height of
at least twenty or thirty feet." A
tree has three principal parts or sys-
tems; they are the roots, the leaves or
foliage, and the stem or trunk. The
roots and the foliage are here regarded
only as they are means by which the
wood of the stem is manufactured.

The Roots. — This system of branches
is as extensive as the one at the top
of the tree. Roots serve in two ways:
(1) they give stability and hold the
tree firmly in its place; (2) they absorb
moisture and various nutrient salts
from the soil. With the exception of
carbon and some oxygen used in
respiration, all of the elements needed
for the growth of trees are obtained from the soil through their
roots.

REFERENCES. — " Cyclopedia of American Horticulture," Bailey; "Fores-
try for Farmers," Fernow (United States Division of Forestry Bulletin No.
10); "First Book of Forestry," Roth; "Outlines of Botany," Leavitt
(American Book Company); "Plant Anatomy," Stevens (Second Edition).

8

FIG. 3. — Roots, a, Cross-
section through root; 6,
hairroots enlarged.

PHYSIOLOGY OF TREES— FORESTRY

I— One year
J old

The Leaves. — Carbon, in the form of carbon dioxide, is ob-
tained from the atmosphere by means of the green coloring matter
which forms part of the leaf and which is known as chlorophyll.
Leaves also serve as laboratories within which food materials
are formed which may finally enter into the formation of wood.

By some peculiar property of the chlorophyll, the living tissue
of the leaf is able, in the presence of sunlight, to split apart the
C02 and to recombine the constituents with H20 so as to form a
carbohydrate, probably some form of sugar. 1
The chemical formulas of grape sugar
(C6H12O6) and cellulose (C6H10O5) are
essentially alike, so it is clear that, with the
development of carbohydrate compounds
in the leaves, a fundamental step has been
taken toward the formation of wood.

The Trunk. — The trunks of trees that
yield banded woods must be distinguished
from the trunks of trees that yield non-
banded woods. In the first group, the
wood-elements are arranged in concentric
bands or layers, while in the second group
they are distributed in separate bundles so
that the cross sections, in this case, appear
as though dotted (Figs. 1 and 2).

All trunks increase in two ways : in length
and in thickness. Increase in length is
quite distinct from increase in thickness.
The terms length-growth and thickness-
growth will be employed to indicate these
two methods of increase.

Length-growth. — All trees lengthen by
means of material that forms upon the
ends of the main axis and of the twigs
and branches. A point of embryonic cells
exists at the end of each ultimate twig.
These apical cells grow, divide, and in the course of the year
leave behind them a whole new section of twig with its leaves.
The twig then thickens by a centrifugal growth to be described,
and eventually the twig becomes a part of the bough.

1 "Light in Relation to Tree Growth," Zon and Graves (United States
Forest Service, Bulletin No. 92.)

.Hwo years

old

10 ORGANIC STRUCTURAL MATERIALS

Length-growth precedes thickness-growth and is quite distinct
from it. A nail driven into a tree at a certain distance up from
the ground may be finally covered by new wood material, but it
will not move up higher from the ground.

Thickness- growth. — With several exceptions, the few trees
that yield non-banded woods do not increase in diameter by the
formation of new layers deposited upon the outside of older
growth. On the contrary these trees increase largely by the
expansion of cells already formed. The trunks of these trees,
few of which are of structural importance, do not continue to
increase in diameter throughout their lives, but normally attain
maximum diameters comparatively early in their growth.

The trees that yield banded woods thicken as follows:

During the first year, the wood material is in separate
bundles arranged in a circle, but later these bundles are fused
together so as to form a more or less compact cylinder. The

a 6 c

FIG. 5. — Cross-section of very young banded stem, a, Six fibro-vas-
cular bundles are shown, b, The same stem later; the bundles are increased
to twelve, c, At the end of the year the bundles are in the form of wedges
separated by pith rays. Acknowledgments to "Outlines of Botany,"
Leavitt (American Book Company).

tissue known as primary wood is included in this early growth.1
The several stages during the first year are sufficiently indicated
in the pictures.

After the first year, the food materials, which are formed in
the leaves, descend to the growing part where the new wood
is formed. This part is known as the " cambium layer." Wood
formed from the cambium layer is known as secondary wood.
Practically all of the wood formed by the tree is of this kind.
After the first year a new layer of secondary wood is formed
every growing season, and these annual layers or bands are
characteristic of all banded woods.

1 Tissue at the growing end of the twig forms primary wood. The thin-
walled cells of which it is composed are essentially similar to one another.

PHYSIOLOGY OF TREES— FORESTRY 11

The Cambium Layer. — This part, which is of fundamental
importance to the life of the tree, occupies the region between the
sapwood and the bark, and may be described as a thin-walled
formative tissue within which, by cell-division, growth, and
modification, all wood-elements originate. The cambium layer
consists of essentially the same kind of embryonic cells as those
at the tips of the twigs.

The cambium layer, which suggests a thin layer of mucilage, is com-
posed of very thin-walled cells, filled with protoplasm, and other organic
and nutrient compounds. These cells multiply and develop. The inner
cells eventually form a new layer of wood while those at the outside form
bark. The wood cells, which are at first soft and delicate, become
harder, as a material known as lignin begins to be deposited within their
walls. The resulting change from the soft cell to the tough, woody cell
is known as lignification.

The cambium, in its centrifugal advance, may leave one hun-
dred or more thin layers of wood-elements behind every year and
these very thin deposits together make up what is commonly
known as the " annual band" already mentioned.

Sap Movement. — In the trees that yield banded woods, the
" crude sap," containing mineral nutrients drawn from the soil,
leaves the roots and passes upward through the outer sapwood to
the foliage where the sap is by complex chemical changes " elabor-
ated." The elaborated or completed sap, containing the more
complex organic preparations needed for the life of the tree, then
descends through the inner bark to the growing parts.

The fluids of a tree move continuously during the growing
season. Up-currents and down-currents move simultaneously.
In the main, fluids pass upward through the outer sapwood and
downward through the inner bark, as has been noted. This
continues through the larger part of the year and is not confined
to the spring alone as some suppose.

The means by which sap ascends to the top of the tree are not
fully understood, but evidence exists that the force is not capillary
to the extent that was formerly supposed. The passage upward
is doubtless encouraged by the evaporation of water from the
leaves, but how far this acts in raising the water through dis-
tances as great as several hundred feet is not known.1

iSee "Tracheids."

12

ORGANIC STRUCTURAL MATERIALS

Influence of Sunlight. — All trees require sunlight and are
influenced by the way in which they receive it. A tree that
stands by itself in the open will differ in form from a tree that
stands with others in the forest. In the former environment, the
growth of lower branches is encouraged, while in the latter
environment, it may be discouraged. Sunlight does not have
free access to the side branches of ordinary trees standing near
together in a forest. The higher branches of such trees are there-
fore better nourished. These extend upward toward the sun-
light, and consequently longer, cleaner trunks are formed.

FIG. 6. — Sugar maple tree grown in the open. (By courtesy of American
Museum of Natural History.)

It is possible to modify the shapes of trees. Either full-
branched trees, that are prized in landscape effects, or long,
straight trunks that are valued by lumbermen can be obtained
by proper exposure to sunlight. The lower branches of many
forest trees are pruned away by nature, that is, these branches
die naturally for want of sunlight. In other cases the same
results are obtained by ordinary pruning. In any case where
lower branches are removed, wood-making material which would
otherwise pass into these branches is diverted to the trunk.

The value and influence of sunlight are described in the follow-
ing quotation:1

1 " Light in Relation to Tree Growth," Zon and Graves (United States
Forest Service Bulletin No. 92).

PHYSIOLOGY OF TREES— FORESTRY

13

"Light is indispensable for the life and growth of trees. In common
with other green plants a tree, in order to live, must produce organic
substance for the building of new tissues. Certain low forms of vege-
table life, such as bacteria and fungi, do not
require light. They exist by absorbing organic
substance from other living bodies; but the
higher forms of plants manufacture their own
organic material by extracting carbon from the
air. The leaves, through the agency of their
chlorophyll, or green coloring-matter, absorb
from the air carbon dioxide, and give off a
nearly equal volume of oxygen. The carbon
dioxide is then broken up into its elements and
converted into organic substances which are
used in building up new tissues.

"Light is not only indispensable for photo-
synthesis, but it is essential for the formation
of chlorophyll. Only in exceptional cases, as in
the embryo of fir, pine, and cedar seeds, does
chlorophyll form in the dark, and, with the
exception of some microbes, the green cell is
the only place where organic material is built
up from inorganic substances.

"Light also influences transpiration, and
consequently the metabolism of green plants.
It influences largely the structure, the form,
and the color of the leaf, and the form of the
stem and the crown of the tree. In the forest
it largely determines the height-growth of
trees, the rate at which stands thin out with
age, the progress of natural pruning, the
character of the living ground cover, the vigor
of young tree growth, the existence of several-
storied forests, and many other phenomena
upon which the management of forests depends.
A thorough understanding, therefore, of the effect of light upon the life
of individual trees, and especially on trees in the forest, and a knowledge
of the methods by which the extent of this effect can be determined
are essential for successful cultural operations in the forest."

VALUE OF FORESTS. — The top- soil of forests is porous and
loose. The mixture of leaves and loose top-soil that forms under
the trees is known as " humus." The humus receives and pro-
tects young seeds and is also valuable because it assists in equal-
izing the flow of streams.

FIG. 7. — Tulip tree
grown in the forest.
(Courtesy of the
American Museum
of Natural History.)

14

ORGANIC STRUCTURAL MATERIALS

Rain-water rolls quickly from sun-baked or otherwise com-
pacted soil, but humus permits the raindrops to pass through
into the more or less broken and comparatively loose and porous
soil below and then obstructs the free evaporation of moisture
from this soil. It is not known that forests influence rainfall,
but their value in regulating stream-flow is beyond estimate.1

FIG. 8. — Ability of Surface Materials to hold Water. A, Most of the water
in this bottle, which contains gravel, has passed through into the beaker.
B, C, and D, These bottles contain sand, barren soil and loam. E, This
contains leaf mould, which retains the most water. F, This contains leaves.
(From "Trees and Forestry," Dickerson. By permission American Museum
of Natural History.)

Forests Reduce or Prevent Erosion. — The humus protects the
surface, and the roots contribute to the resistance offered by the
soil below. Water flows with erosive force over unprotected
and hardened surfaces. Quantities of soil are carried from
higher elevations and deposited on lands below. Such results
may be far reaching. Districts such as parts of India, China,
Palestine, and Spain, that have supported considerable popula-
tions in the past, have been changed in this way and are now
little else than deserts.

xLeighton estimated that the flood damages to this country amounted
to $237,800,000 in 1908; "Conservation of Natural Resources in the United
States" (Van Hise, p. 182). See also Swain in "American Forestry,"
April, 1910, and Burr in "Engineering News," July 27, 1911, etc.

PHYSIOLOGY OF TREES— FORESTRY 15

The possibilities in this direction are described further as
follows (Van Hise1) :

"Not only so, but after the rivers are partly filled with silt, at times
of flood they overflow their banks and often cover with coarse debris
large areas of arable land. When this process of erosion has continued
for a sufficient length of time after the removal of the forests, the steep
mountains are left with nearly bare rock and little soil. When this
stage of the process has been reached the violence of the floods is then
further greatly increased. The rain falling upon the bare rocks is car-
ried down to the streams below as from the roof of a house, and unites
in torrential floods. It is after this condition of affairs has come about
as a result of a removal of the forests that the enormous flood losses
occur to railroads, cities, and other structures of man."

FORESTRY. — Forestry is a phase of agriculture, rather than
of lumbering. Under this system forests are not destroyed for
immediate profit but are maintained so as to secure recurring
crops of desirable, matured trees. Besides this, appropriate
species are planted, top-soil or humus is preserved, fire risks are
lowered, and young trees are introduced as older ones are cut
down. Forestry yields smaller profits but these continue from
year to year. The lumberman, who disregards the principles
of forestry, receives larger profits once and for all.

The results that may be obtained by the practice of forestry
are expressed in the quotations that follow :2

"Under right management our forests will yield over four times as
much as now. We can reduce waste in the woods and in the mill at
least one-third, with present as well as future profit. We can perpetuate
the naval-stores industry. Preservative treatment will reduce by one-
fifth the quantity of timber used in the water or in the ground. We
can practically stop forest fires at a total yearly cost of one-fifth the
value of the standing timber burned each year." .... "By reason-
able thrift we can produce a constant timber supply beyond our present
need and with it conserve the usefulness of our streams for irrigation,
water-supply, navigation, and power."

1 "Conservation of Natural Resources in United States" (p. 246). See
also "Washed Soils and How to Prevent Them" (United States Dept.
Agriculture, Farmers' Bulletin No. 20); "Conservation of Water by Stor-
age," Swain (Yale University Press, 1915).

2 United States Forest Service Circular No. 171, Price, Kellogg and Cox.

16 ORGANIC STRUCTURAL MATERIALS

The size and character of the trunk, and the range, locality,
and distribution of the species, have much to do with the utility
of the wood. Large and perfect timbers cannot be derived from
species characterized by small or crooked trees. A given kind
of wood is always used more if it is widely distributed and easily
available.

CHAPTER III

WOOD. CHARACTER AND ARRANGEMENT OF WOOD-ELEMENTS.
INFLUENCE OF CELLULAR STRUCTURE UPON CHEMICAL
COMPOSITION AND PHYSICAL PROPERTIES OF WOODS.
IDENTIFICATIONS. STATEMENTS OF WEIGHTS AND MODULI
EMPLOYED IN TABULAR DESCRIPTIONS OF SPECIES

Wood is the solid part of trees — the part which, when otherwise
suitable, is used in construction. It consists of a ground-work of
starch-like substance known as cellulose, permeated by materials
collectively known as lignin. There are also secretions, such as
resin, coloring-matter, and water. The small proportion of
mineral in wood is evident as ash.

Wood, timber, and lumber may not mean the same. Prop-
erly speaking, all woody tissue is wood; but roots and branches
contain much wood that is not suitable for construction. Wood
that is suitable, although not necessarily ready, for construc-
tion, is "timber;" and wood that is not only suitable, but also
ready for construction, is "lumber." The word timber may
thus include living trees in the forest, as well as logs and shaped
pieces; whereas, lumber refers only to boards, planks, beams,
and other sawn pieces of limited sizes, and then only in America.
The term lumber, which is not sharply definable, is not used
much outside of North America.

Wood is composed of innumerable minute structural units,
known as wood-cells,1 or wood-elements, which differ from one

1 So named by Robert Hooke in 1667 because of resemblance to cells of
honeycombs.

REFERENCES. — "Structure of Certain Timber Ties," Dudley (United
States Forest Division, Bulletin No. 1, p. 31); "Timber," Roth (United
States Forest Division, Bulletin No. 10); "The Decay of Timber," von
Schrenk (United States Bureau of Plant Industry, Bulletin No. 14, p. 12);
"Trans. American Railway Engineering Association," Tiemann (Bulletins
No. 107 and No. 120); "Plant Anatomy," Stevens; "Identification of
Economic Woods of United States," Record (John Wiley & Sons, 1912);
"Wood," Boulger (London, Second Edition); "North American Gymno-
sperms," Penhallow; "Outlines of Botany," Leavitt; "Pithray Flecks in
Wood," Brown (United States Forest Service Circular No. 215); etc.

17

18

ORGANIC STRUCTURAL MATERIALS

another in shapes and sizes, in the thickness and surfaces of their
walls, and in the ways in which they are arranged. There are
also compounds associated with, although actually foreign to, the
wood-elements. Of these associated materials, water is the most
important.

The subject is fundamentally important. Physical properties,
such as hardness, elasticity, and weight are influenced by (1) the

FIG. 9. — Pits. A, Longitudinal section through parts of two adjoining
walls w.w. One pair of bordered pits 6. p., is shown. B, Longitudinal sec-
tion through portions of two adjoining wood-fibers. Four pairs of simple
pits in adjoining walls are shown; only one pair is marked s.p. The lumen
of each fiber is marked 1. The walls are marked w. C, Cross-section
through entire wood-element, with parts of walls of adjoining wood-
elements. Bordered pits are shown on the right, and on the left b. p. The
torus t is the thick part of the common, separating, or primary portion of the
wall also known as the "middle lamella." D, A larger and more detailed
section through bordered pits shown in figure C. Two adjoining pits with
torus and pit-canal are shown.

character of the wood-elements, (2) the arrangement of the wood-
elements, and (3) by the characteristics and quantities of the
compounds that are associated with the wood-elements.

WOOD-ELEMENTS. — These vary in details, but are similar
in this regard that all partake of the nature of minute tubes.
The cavities within the tubes are the "lumina." A cell-cavity,
or lumen, may be empty, or it may contain water or other com-
pounds. Wood-elements are of several kinds, as wood-fibers,

PLATE I. ARRANGEMENT OF WOOD ELEMENTS— CROSS SECTIONS

(a) Cross-section of Longleaf Pine (Pinus palustris) .

(6) Cross-section of White Oak (Quercus alba).

Acknowledgments to Bureau of Plant Industry, United States Department of Agriculture.

(Facing page 18.)

WOODS— WOOD ELEMENTS

19

tracheids, vessels, wood-paren-
chyma fibers, and pith-ray cells.
Each of these classes of wood-ele-
ments includes several varieties.

The walls of all wood-elements are
thickened and appear under the
microscope as double lines.

The young primary wall, is a
very thin, practically imperforate
and continuous membrane, which
constitutes the first outline of the cell.
This membrane originally surrounded
the protoplasm and other materials
that were contained within the living
cell.

The secondary thickening is laid on
later and gives strength to the wood-
element. It is seldom, if ever, im-
perforate, but contains pits of char-
acteristic shapes. The layer is some-
times disposed in ridges on the inside
of the cell, much as a spiral stair-
case is placed within a tower. This
structure is never present within
wood-fibers, but is occasionally found
within tracheids and vessels.

Holes or thin spots in the walls
of wood-elements are known as
"pits." Some pits are round, while
others are elliptical or slit-shaped.
They are further divided into what
are known as "simple pits" and
"bordered pits." Pits are "simple"
when the walls that extend out from
the middle lamella are nearly parallel,
and they are "bordered" when the
walls that extend out from the middle
lamella diverge.

The bordered pits that are present
in the walls of tracheids, vessels,
and some wood-fibers, are invaria-

-c.w.

(Nyssa sylvaticd).

gu _ _

Wood-fibers of black walnut (Juglans nigra).
indicates lumen; s.p. indicates simple pit.

FIG. 10.— Wood-fibers. A,
Wood-fiber of white oak (Quercus
alba.) B, Wood-fiber of black
C, Wood-fiber of beech (Fagus americana). D,
c.w. indicates cell-wall; I

20

ORGANIC STRUCTURAL MATERIALS

FIG. 11. — Tracheids. A,
Tracheid of yew (Taxus
bacata). B, Tracheid of
pinon pine (Pinus edulis).
C, Tracheid of red oak
(Quercus rubra). D, Tra-
cheids of western yellow
pine (Pinus ponderosa) .
b.p. indicates bordered pit;
s.p. indicates spiral.

bly paired exactly in position with similar pits in the walls of ad-
joining elements. They do not open through, however, but are closed
by partitions which exist in the primary walls or "middle lamellae."
There is usually a thickened disc in the middle of the partition that
is known as the "torus."

Wood-Fibers. — Ordinary wood-fibers are long, slender, com-
paratively smooth-surfaced, and sharp-pointed wood-elements.
The walls are thick and lignified, and the pits are usually simple;

that is, they are without borders.
Wood-fibers are not found in conif-
erous woods, but are nearly always
present in, and are regarded as char-
acteristic of the so-called broadleafed
woods to which they contribute much
strength and hardness. The wood-
fibers also give mechanical strength
to the living tree and probably con-
tribute in some way to the transporta-
tion of water through the tree, from
the roots to the foliage.

Tracheids ( Tra-ke-ids).— Tra-
cheids are elongated, taper-pointed
cells, with peculiar markings, which
appear, either in the form of bordered
pits, located, for the most part, on
the radial surfaces of the tracheids,
or else in the form of ridges, variously
disposed upon the inner walls. Tra-
cheids are the wood-elements upon
which coniferous woods largely de-
pend for strength. They are charac-
teristic of coniferous woods and
although they do exist in many of
the broadleafed woods are then in-
variably subordinate to wood-fibers
and vessels.

Tracheids serve in the living tree
because they contribute to its me-
chanical support, and also because the
bordered pits are so designed as to
assist very materially in the conduc-
tion of water through the stem from the roots to the leaves.

b.f>-

b.p

WOODS— WOOD ELEMENTS

21

-b.p.

p.w.-

The means by which water is thus raised has been credited to
root pressure, transpiration, and osmotic pressure.1

Vessels. — These compound structures are formed by the
breaking down of partitions that exist between the abutting ends
of simpler or shorter structures, known as "vessel-segments."
Tubes of very considerable length are formed in this manner and,
as is the case with oak, are
often so large in diameter
that they can be seen with
.the unaided eye. These
large cavities are commonly
referred to as "pores," and
the vessels themselves have
been variously named by
plant anatomists as pores,
canals, ducts, tubes, vasa,
tracheae, tracheal-tubes,
and fistulae.

Vessels Differ with Spe-
cies.— The central cavities
of lumina of the vessels of
some species are open,
while those of other
species are obstructed by
parenchymatous growths
known as "tyloses." Air
can readily be blown
through several feet of red
oak, even before it has
been seasoned, because tyloses are absent in the vessels of this
species. On the contrary, a pressure of one hundred pounds
per square inch is sometimes insufficient to force air through a
single inch of unseasoned white oak, because the vessels of that
species contain quantities of tyloses.

A vessel increases in thickness by means of layers that are gradually
deposited on its walls. Several layers of unequal thickness can often
be distinguished with the aid of a powerful microscope. The thick-
ened portions of the walls give strength, while the unthickened por-
tions permit water and materials in solution to pass in and out. The
differences in thickness are evidenced by markings such as are shown
in the picture.

C

FIG. 12. — Vessel-segments. A, Vessel-
segment of cotton gum (Nyssa aquat-
ica). B, Vessel-segment of black walnut
(Juglans nigra). C, Vessel-segment of
oak (Quercus). sc.p. indicates scalari-
form (ladder-like) perforations; b.p. and
p.w. indicate bordered pit and partition
wall respectively.

1 "Plant Physiology," Jost (Gibson, Oxford, 1907, pp. 45-47.)

22

ORGANIC STRUCTURAL MATERIALS

Wood-Parenchyma Fibers ( Pa-ren-kih-ma ) . — These com-
paratively short, compound structures are made up of shorter,
oblong, thin-walled cells, in groups, from a few in number
to as many as eight or ten, of which the upper and lower cells
are taper-pointed. Wood-parenchyma fibers resemble fibers and
tracheids in general form, but differ from them in that, as groups
of living cells, they contain, besides proto-
plasm, the various foods and products
connected with the life-processes of the
tree. They may contain crystals of
calcium oxalate or crystals of calcium
carbonate. The cells that contain these
crystals are often cubical in outline and
the cavities are sometimes completely
filled with the crystalline mass. Such
elements are known as "idioblasts."

Wood-parenchyma fibers are usually,
although not always, shorter than wood-
fibers in the same species. They are pecu-
liar, in that they retain their power of cell-
division after they leave the cambium, and
usually divide into a number of short
parenchyma-cells, separated by horizontal
or oblique partition- walls, as has been
noted. There are simple pits that on the
whole vary only slightly in different species
of woods. Sanio, author of the term " wood-
parenchyma fiber," describes them as tis-
sues that originate through the division of
cambium cells and that conduct and store
up carbohydrates. He divides them into
two classes, namely, septate and non-septate
or intermediate wood-parenchyma fibers.
The latter are sometimes difficult to dis-
tinguish from wood-fibers, but usually have

A B

FIG. 13. — Wood-par-
enchyma fibers. A,
Wood-parenchyma fiber
of white oak (Quercus
alba). Bj Wood-paren-
chyma fiber of black
walnut (Juglans nigra).
w.p.c. indicates wood-
parenchyma cell; s.p. in-
dicates simple pit; c.w.
indicates cell-wall; ex.
indicates cell-cavity ; c.
indicates crystal of cal-
cium salts.

thinner walls and larger cell-cavities.

Solereder classifies wood-parenchyma fibers with wood-fibers, vessels,
and tracheids, under the general term " wood-prosenchyma, " and not
with pith-ray elements.1

igee also "Wood," Boulger (Second Edition, pp. 28 and 29); "North
American Gymnosperms," Penhallow (p. 109).

PLATE II. ARRANGEMENT OF WOOD ELEMENTS— TANGENTIAL

SECTIONS

(a) Tangential Section of Longleaf Pine (Pinus palustris).

(b) Tangential Section of White Oak (Quercus alba) showing large Pith

Ray.

Acknowledgments to Bureau of Plant Industry, United States Department of Agriculture.

WOODS— WOOD ELEMENTS

m.r.c. -

rt

t

©_

©

-re:

~r.t

C D

FIG. 14. — Pith-rays. A and J5, rPith-rays in radial and tangential sec-
tions of black walnut (Juglans nigra). C and D, Pith-rays in radial and
tangential sections of western yellow pine (Pinus ponderosa). p.r. indi-
cates pith-ray ; t indicates tracheid ; c.w. indicates cell wall; r.t. indicates ray
tracheid; r.c. indicates ray cells; m.r.c. indicates marginal ray cell; s.p. indi-
cates simple pit; r.d. indicates resin-duct; r.c. indicates resin-cell.

24 ORGANIC STRUCTURAL MATERIALS

Pith-rays. — These compound structures are made up of
short, cubical or oblong cells, arranged in rows that pass radially
from the center of a tree to its circumference. Pith-rays differ
strikingly from other wood-elements in that they are arranged
horizontally. They cross the tree, bind the vertical wood-ele-
ments together, and also serve as a vital link between the living
elements of the tree. The cells of which pith-rays are composed
resemble those making up wood-parenchyma fibers in form
and structure, and because of the fact that they, too, contain
various foods and products connected with the life-processes of
the tree. The terms pith-ray, medullary ray, and ray mean
the same.

Pith-rays are plainly visible in some woods, as oaks, but are not
easily visible in other woods, as poplars, even when a hand magni-
fying glass is employed. Pith-rays contribute to the appearance
of "quartered oak," which with other " quartered woods," are
obtained by cutting logs radially (see Fig. 25). When cut in
this way the pith-rays are split and their larger surfaces are
exposed. Otherwise, in the tangential cut, the pith-rays are cut
through vertically and appear as short lines. Pith-rays are not
visible in some woods except when very thin pieces are placed
under a compound microscope.

The small, cubical or oblong cells, of which pith-rays are composed,
are indented with minute, simple pits. The pith-rays of some conifers
also contain, in addition to the small parenchyma cells, one or more
rows of peculiar flattened tracheids, known as "ray-tracheids." Resin-
ducts are also present in some of the pith-rays that exist in the pines.
Pith-rays may be divided into primary and secondary pith-rays. The
first are those that extend completely through from the pith-cavity at
the center of the tree to the bark, while the second are those that do
not extend through thus completely.

The function of the pith-ray has been described as follows:1

"The medullary-rays have, for their primary function, the radial
transmission and storage of food. Their intimate relation with the cells
of the phloem at their outer and with the xylem parenchyma along the
inner course, and the fact that we usually find them gorged with food,
points to this conclusion. The short, vertical extent of the rays, and
their isolation from each other renders them unsuited for the vertical or
longitudinal transmission of foods. If they were of value in this respect
girdling would not prevent the downward flow of foods."

1 "Plant Anatomy" Stevens (p. 162).

WOODS— WOOD ELEMENTS

25

Resin-canals. — Resin-canals are not wood-elements like tra-
cheids and wood-fibers. On the contrary, they are inter-
cellular passages which appear scattered irregularly here and
there throughout the woods of some coniferous trees. They are
not numerous and do not form conspicuous structural features
in the cross-sections in which they occur. The continuity of
the passages through some of these canals, as those in Douglas

Pr

w.p c.-

FIG. 15. — Resin-canal. Resin-canal in transverse section of western
yellow pine (Pinus ponderosa). r.c. indicates resin-canal; e.p.c. epithe-
lium cells; w.p.c. wood-parenchyma cells; p.r. pith-ray; t. tracheid; b.p.
bordered pit; and c.w. cross-wall.

fir, is interrupted by constrictions. In some woods resin-canals
are simple cavities known as " cysts." Resin-canals and resin-
ducts are the same.

The resin-passages that exist in the trees that produce commercial
resins have received most attention. Tschirch divides these passages,
as they exist in the pines, into " primary resin-ducts " and "secondary
resin-ducts." The former, scattered through the heartwood and the
sapwood, produce comparatively small quantities of resins, while the
latter, formed in the outer sapwood of trees that have been wounded,
pour crude turpentine over the wounded surfaces in order to protect
them. The turpentine of commerce is obtained from these "secondary

26 ORGANIC STRUCTURAL MATERIALS

resin-canals." It will be seen that the resins produced by the " primary
canals" are physiological products, whereas those produced by the " sec-
ondary canals" are pathological products. Tschirch has demonstrated
that the seat of resin-production is in a mucilaginous layer (epithelium
cells, Fig. 15) that lines the inside of the resin canal.1

Arrangement of Wood-elements. — The character of wood
depends not only upon its wood-elements but also upon the
way in which these wood-elements are arranged. Most wood-
elements are arranged up and down, a fact that explains
the comparative ease with which most woods are split. But
besides this, there is a horizontal arrangement. The pith-rays
pass radially, that is horizontally, from the center of the tree to
its circumference, and bind the vertical wood-elements together.
The arrangement of wood-elements is much more regular in some
woods, as pines, than in others, as eucalyptus and lignum vitae;
and woods are easy or difficult to work, in proportion as their
elements are thus arranged in a simple or a complicated manner.

Associated Compounds. — Certain materials are associated with,
although they do not form part of, the wood-elements, and such
compounds are notable because they exert a material influence
upon the character of the wood-elements, and, therefore, upon
the character of the wood. Of these associated materials, the
most important is water, which acts by distending the wood-
elements and thus making them weaker and more pliable. The
influence of moisture is so great as to require further notice (see
" Moisture in Wood").2

Influence of Cellular Structure upon Chemical Composition
and Physical Properties of Wood. — Chemical and physical prop-
erties of woods are influenced by the character and arrangement
of the wood-elements, and by the qualities and quantities of the
materials associated with these wood-elements. Chemical com-
position, strength, weight, appearance, and other properties re-
garded by those who use woods depend much upon these details.

1 "Resin-Canals in White Fir," Mell (American Forestry, June, 1910);
"Relation of Light Chipping to the Commercial Yield of Naval Stores,"
Herty (U. S. Forest Service, Bulletin No. 90).

2 "Sap in Relation to the Properties of Wood," Record (Proc. American
Wood Preservers Association, Baltimore, Md., 1913, pp. 160-166); "Effect
of Moisture upon the Strength and Stiffness of Wood," Tiemann (United
States Forest Service Bulletin No. 70 and United States Forest Service
Circular No. 108).

WOODS— WOOD ELEMENTS

27

Identification of Woods. — External appearances differ and
are hard to describe. Colors vary, even in pieces cut from the
same tree ; moreover, colors are not permanent, but often change

FIG. 16. — Dissection showing waving cell arrangement in a specimen of

curly redwood.

with age and exposure. Artisans become familiar with the
working qualities of a few woods, but are commonly uncertain
with regard to the working qualities of other woods. On the
whole, the character and arrangement of the wood-elements

28

ORGANIC STRUCTURAL MATERIALS

afford the only reliable basis upon which many woods can be
finally identified. Some of the cellular characteristics of woods
are evident to the naked eye, but, in most cases, the microscope
is required.

The cellular characteristics of woods are most evident in their
cross-sections. The cross-sections of different species differ
from one another, but each one exhibits certain traits that remain

FIG. 17. — Photomicrograph of spruce (cross-section). Thought to be about

500,000 years old.1

constant for that species, and in many cases these traits are suffi-
cient to serve as a means of practical identification. For example,
it will be noted that the section of white oak (Plate I) contains
large vessels but is without resin-ducts, whereas the section of long-
leafed pine (Plate I) contains resin-ducts but is without vessels.

footnote, p. 29.

PLATE III.

ARRANGEMENT OF WOOD ELEMENTS— RADIAL
SECTIONS

(a) Radial Section of Longleaf Pine (Pinus palustris).

(6) Radial Section of White Oak (Quercus alba}.

Acknowledgments to Bureau of Plant Industry, United States Department of Agriculture.

(Facing page 28.)

WOODS— WOOD ELEMENTS

29

The identification of a log removed from an ancient forest bed is
described by Koehler.1 The extent and character of the soil and other
material deposited upon the log caused geologists to believe that it was
500,000 years old. The wood was brittle, and much distorted, most of
the cell-elements being flattened. But when under a microscope the
characteristic structure of the wood was revealed. The wood was re-
ported as Spruce. (See Figures 17 and 18.)

FIG. 18. — Photomicrograph of fresh spruce (cross-section).1

Banded woods may be easily distinguished from non-banded
woods by the presence or absence of yearly bands, layers, or rings
(Figs. 1 and 2); while the- needleleaf and broadleaf woods, which
together make up the banded woods, may be told from one an-
other by noting the differences shown in the table that follows
(Record2) :

1 From " Wood Older than the Hills," Koehler, by Courtesy of The Ameri-
can Forestry Magazine, Washington, D. C. (February, 1916).

2 " Identification of Economic Woods of the United State \t " Record (p. 13).

30

ORGANIC STRUCTURAL MATERIALS

BANDED WOODS

Needleleaf Woods, Softwoods
(Conifers).

True vessels absent.

Wood tracheids present and form-
ing bulk of wood.

Ray tracheids present or absent.

Wood fibers absent.

Wood parenchyma present (ex-
cept in Taxacese), but usually
subordinate.

Ray parenchyma present.

Broadleaf Woods, Hardwoods
(Dicotyledons).

True vessels present.

Tracheids present or absent; al-
ways subordinate.

Ray tracheids absent.

Wood fibers present.

Wood parenchyma present, and
very often conspicuous.

Ray parenchyma present.

The key prepared by Fernow and Roth1 is based upon a divi-
sion of banded woods into three classes, namely: non-porous
woods, ring-porous woods, and diffuse-porous woods. The dis-
tinctions are as follows:

1. Non-porous Woods. — The pores (vessels) of these woods are not
evident, even with magnifiers. The annual layers are distinguished by
means of denser, dark-colored bands of summer-wood (see Fig. 19A).
This group includes the pines and other so-called softwoods.

2. Ring-porous Woods. — The numerous pores (vessels) are usually vis-
ible even without magnifiers. The pores are collected in the spring
•deposits, which thus contrast with the denser summer- woods. This
group includes oak, ash, catalpa, chestnut, black locust, hickory, per-
simmon, and others (see Fig. 19B).

3. Diffuse-porous Woods. — The numerous pores (vessels) are not col-
lected in the spring-wood as in the case of the ring-porous woods, but
are scattered throughout the entire annual layer. The pores are not
usually visible without magnifiers. This group includes cherry, maple,
beech, black walnut, holly, sycamore, cottonwood, and others. (See
Fig. 19C.)

The value of cross-sections, which are more serviceable than
radial or tangential sections in making microscopic examinations
of woods, is influenced by the tools that are used to prepare these
sections. Smooth surfaces are desired and, therefore, very sharp

1 "Timber," Fernow and Roth (United States Forest Service Bulletin
No. 10, pp. 59-83). See also "Identification of Economic Woods of
the United States," Record (John Wiley & Sons); "Confusion of Technical
Terms in Study of Wood Structure," Mell (Forest Quarterly, Vol. IX, 1911,
No. 4, pp. 574-576) ; " Wood," Boulger (Second Edition, London) ; etc. The
actual sections prepared by Hough are very helpful. "The Jesup Collection
of Woods" at the American Museum of Natural History is, available for
those living near New York City.

WOODS— WOOD ELEMENTS

31

tools should be employed. If the tools are not sharp, the surfaces
will be rough and the characteristic features obscure. A shaving
cut by a well-sharpened plane is sometimes sufficient, but, for
more technical work, a microtome is necessary. Sections should
be cut precisely at right angles to the vertical axis of the tree,
since otherwise the rounded sections of the vessels appear as
ovals.

A B C

FIG. 19. — Original photomicrographs. A, Cross-section of non-porous
wood (longleaf pine). B, Cross-section of ring-porous wood (white oak).
C, Cross-section of diffuse-porous wood (sweet gum).

For ordinary examinations, any microtomes, save those of
the rotary type, are serviceable. The instrument shown in
the picture gives excellent results. Compound microscopes
manufactured by the Bausch & Lomb Optical Company of
Rochester, and by the Spencer Lens Company of Buffalo, are
very satisfactory.

32 ORGANIC STRUCTURAL MATERIALS

Identification of Trees. — Trees are not always easily iden-
tified by laymen. Forms in the forest differ from those in the
open. Bark varies with age, while leaves and fruit are often
lacking in the winter. Most laymen find it easier to tell genus
than species. They know that a tree is an oak, but do not know
whether it is a red oak or a pin oak. Experience is required.
Sargent's " Manual of the Trees of North America," and Hough's
" Handbook of Trees of the Northern States and Canada"

FIG. 20. — Modification of Jung-Thoma microtome for cutting wood, as
described by Thomson, University of Toronto, in Botanical Gazette, August,

iy lu.

are convenient reference books, while Hough's "Leaf Key to
Trees" and Ernest Thompson Seton's "Foresters' Manual" are
serviceable in the field in identifying trees that are in summer
condition. l

1See also Bibliography.

WOODS— WOOD ELEMENTS 33

WEIGHTS AND MODULI.— It seems best thus early to introduce
the two series of weights and moduli to be employed in the tabu-
lar descriptions of species that form part of succeeding chapters.
Further descriptions and the reasons for preferring these par-
ticular series of figures will be given later. The figures referred
to are as follows :

First. — Results of experiments conducted by the National Forest
Service. These figures occupy the leading spaces in the descrip-
tions of species (Chapters V, VI, VII, and VIII) under the titles
of "Weight," "Modulus of Elasticity," and "Modulus of Rupture."
Results have not yet been obtained for all of the species thus de-
scribed so that some of the spaces set apart for the figures reported
for the National Forest Service are vacant.

Second. — Results of experiments conducted by the Watertown
Arsenal for the Tenth United States Census. These figures appear
in the spaces immediately following those occupied by, or set apart
for, the National Forest Service figures.

Weights are given in pounds, and coefficients in pounds per square
inch. Fractions of pounds and lower figures in coefficients have
been omitted as superfluous. l

JSee also Chapter IX.

CHAPTER IV

BANDED TRUNKS AND WOODS

(Conifers and Dicotyledons)

The trunks from which banded woods are obtained grow in
thickness from the outside. The new layers of wood are deposited
upon the outside of others that were formed before. Practically
all of the woods that are used in construction are of this type.
The forest sources are widely distributed, and the numerous
species present an almost infinite range of possibilities.

PARTS OF A BANDED TRUNK.— A section through a banded
trunk is made up as follows: A point or pith-cavity exists at
the center of the section : This pith-cavity is surrounded by con-
centric rings made up of layers or
bands of heartwood and sap-wood,
which together constitute the wood,
or xylem. The entire section is
surrounded by bark, the succulent,
fibrous inner part of which is the
phloem. The line of separation
between the bark and wood is the
cambium. The wood-elements,
the bands or layers in which they
are arranged, and some character-
istics of the bark, the sapwood, the
heartwood, and the pith are im-
portant.

Wood-elements. — The character-
istics of fibers, tracheids, and other wood-elements have been
described. So far as is known, there are no wood-elements that
are particularly associated with the banded woods alone. Some
wood-elements may be modified in certain cases, but the same
kinds exist in both banded woods and non-banded woods.

Annual Bands, Rings, or Layers. — The wood-elements that
stand vertically are arranged in concentric bands or layers one
of which is formed every growing season between the bark and
the wood that was formed during the preceding season. Each

34

FIG. 21. — Section through
young stem of box elder. Pith
cavity surrounded by three an-
nual deposits of wood. The
whole enclosed by bark, b. The
radiating lines p.r. are pith-rays.
The cambium is at c.

ANNUAL DEPOSITS— DEFECTS

35

one of these bands or layers encloses all of the other bands or
layers that were formed before, and each one will eventually be
enclosed by others that are formed later. The bands cover the
trunk and all of the living branches of the tree.

A band or layer is made up of two, more or less, well-defined
parts as follows:

1. Early Growth. — This portion, sometimes referred to as
" spring growth," is formed at a time of the year, when, because
the leaves are unfolding, there is an increased demand for water.

FIG. 22. — Instrument for removing cores to determine ages of trees.1

The more porous water conduction elements preponderate and as
a result this part of the band is lighter, softer, and more porous
than the other. (See Plate I, page 18).

2. Late Growth. — This portion, often referred to as " summer
growth," is formed after the leaves have been fully expanded
and when the cambium can devote itself more exclusively to the
production of the wood-elements that contribute more to strength.
It is, therefore, denser and heavier than the other.

1 The instrument shown in the picture is manufactured by The Keuffe
& Esser Company of New York.

36 ORGANIC STRUCTURAL MATERIALS

The contrasts that exist between the porous early growth and
the more compact later growth of the preceding year serve to
define the limits of the yearly bands.

Bands exist in all needleleaf or softwood trees (conifers), and
in all broadleaf or hardwood trees (dicotyledons), which grow
where there are alternating seasons of wet and dry, or heat and
cold. They also exist, but are often correspondingly less pro-
nounced in localities where the differences in seasons are less
marked. Bands are valuable as means by which the ages of
trees can be determined, and, since they vary in thickness from
year to year as the seasons are wet or dry, they also serve as his-
tory of the local conditions of growth.

The history of a Redwood tree, dating from two hundred and seventy-
one years before the Christian Era, was reported by Professor Dudley
to the United States Senate through the late Senator Platt of Connecti-
cut, on February 11, 1904. The record obtained by counting the con-
centric layers of growth on the cross-section of the felled tree showed
that forest fires had occurred during the years 245, 1441, 1580, and
' 1797 A.D. The last fire was locally severe, since it had charred a space
thirty feet in height and eighteen feet in breadth. It is needless to
state that this tree was exceptionally vigorous or it would not have re-
covered from such a wound. The new tissue, as deposited upon the
outside of this wound, was full, even, and continuous.

The value of the band, layer, or ring as a means by which age
can be determined is indicated in the quotation that follows
(Fernow1) :

"In a young, sound, and thrifty timber, the rings are laid on with the
utmost regularity, and a cross-section of a stem furnishes, therefore, not
only information as to the age of the given section, but is a fair indicator
of the life-history of the tree, periods of suppression and thrift being
indicated, respectively by zones of correspondingly narrow or broad
rings. In such timber, the countings along different radii always give
the same results.

. "If, on the other hand, the rings are very old, especially if slow-grown
stems are counted, it happens not infrequently that counting along one
radius gives one to five rings more than the counting along some other
radius. The reason for this is not always apparent; in some cases, such
a difference in results is due merely to the inability of the eye to detect

1 "Age of Trees and Time of Blazing Determined by Annual Rings,"
Fernow (United States Division of Forestry, Circular No. 16, pp. 2, 3, and 6).

ANNUAL DEPOSITS— DEFECTS 37

an extremely narrow, but otherwise well-defined ring, and the error may
be corrected by microscopical examination. In other cases, however,
the difference is based on the actual absence of one or more rings of
only a given radius, extremely unfavorable circumstances having led
to failure of the regular continuous development of these rings."

Pith (Medulla). — Central pith areas, around which wood is
deposited, are more or less evident in the sections of young trees,
saplings, and young branches. They do not grow in size after
the first year, and in mature trees are usually so compressed as
to be quite obscure. Pith itself is made up of thin- walled paren-
chymatous cells within which food for the rapidly growing parts
is stored, at least in the younger stems. The service which pith
renders to the stem is apparently of a temporary nature.

Heartwood (Duramen). — Heartwood is modified sapwood.
Heartwood gives stability to the tree but is not utilized in its
physiological processes. A tree can survive, even although much
of its heartwood has decayed or been otherwise removed. Heart-
wood is heavier, tougher, stronger, and darker than sapwood.
Its cell-structures are older and its walls appear thicker through
the accumulation of deposited materials. The protoplasm has
disappeared and inert minerals, tannin, gums, and pigments have
appeared. The change from sapwood to heartwood goes for-
ward rapidly in the trees of some species, such as redwood and
locust, and the sections of these trees appear to be almost wholly
heartwood. In trees of other species, the changes take longer.

Von Schrenk believes that sapwood changes to heartwood suddenly;
that the change does not take place in one ring every year, but that it
frequently skips many years, so that eight, ten, or even more rings may
change from sapwood to heartwood in one year. He also calls attention
to the fact that one side of the tree may change before the other, and
that part of a ring may be heartwood, while the rest remains sapwood.1

Sapwood (Alburnum). — This is the younger, lighter-colored,
and more porous wood. It is the part that is directly beneath
the bark, the part that later turns to heartwood. Sapwood is
vitally essential to the life of the tree, but is less durable, and
usually weaker, and less valued in construction than heartwood.
The cell-elements are the same as those in heartwood, but the
latter are usually modified, as was noted in the preceding para-
graph. Sapwood is more pliable than heartwood, and the sap-

1 United States Bureau Plant Industry, Bulletin No. 14, p. 15.

38 ORGANIC STRUCTURAL MATERIALS

woods of several trees, such as hickory and ash, are preferred and
much valued for this reason. The sap currents travel upward
in the sapwood, hence the name.

The wood manufactured by a tree when it is old is usually softer and
weaker than that made by the tree when it is younger. Because of the
time in the life of the tree when it is grown, the sapwood of a large
log may be inferior in strength to equally sound but older heartwood
in the log. The United States Forest Service1 reports upon the com-
parative strength of sapwood and heartwood as follows: " Sap wood,
except that from old, overmature trees, is as strong as heartwood,
other things being equal, and so far as the mechanical properties
go should not be regarded as a defect."

Bark. — This husk or outer cover resembles the wood, although
many of its properties are quite unlike those of wood. Bark is

characteristic of exogenous
trees and assists these trees
in two ways: First, it is an
agent in the physiological
processes of the tree; and
second, it affords protection.
The bark is made up of
several parts. They are as
follows :

1. The phloem, inner, or
FIG. 23.— Compound structure of fibrous bark, is composed

partly of very long, thick-
walled cell-structures, known as "bast fibers." These are the ele-
ments that give character to the stringy bark of the basswood
and the grapevine, and that form the " fiber" of flax from which linen
fabric is woven. These constitute the "hard bast." Associated with
the cell-structures noted above are specialized elongated parenchyma-
cells with their living contents. These constitute the "soft bast"; they
are the sieve tubes and companion cells which serve as channels through
which the elaborated sap passes in its journey from the leaves. These
parts together are known as the "phloem."

2. The living or green part in the middle, called "green bark" or
cortex, is largely composed of rounded parenchyma-cells, which contain
the green substance, chlorophyll, that also exists in the leaves. The
green part of the bark of a twig resembles the substance of a leaf, in
that it also is a tissue which manufactures elaborated food. This layer

1 "Tests of Structural Timber" (United States Forest Service, Bulletin
No. 108, p. 35).

ANNUAL DEPOSITS— DEFECTS

39

loses its green color in older stems because the surrounding " corky
layer" is thick enough to cut out all the light. In the outer portion of
this layer of green bark there are developed regions of "cork-cambium,"
which, by their repeated division, give rise to the outermost or corky
layer.

3. The outermost corky layer is made up of dead and empty cells
derived from the outermost cortex cells, constituting the "cork cam-
bium." The walls of these cells are suberized, that is, they have been
altered and rendered impermeable to water by the addition of a sub-
stance known as "suberin," or cork. This layer serves to prevent un-
due losses of fluids from the tree by evaporation. Moreover, it is a
non-conductor and protects from the cold; it also protects against the
entrance of disease. Composed as it is of dead cells, this cork layer
cannot expand, but is, usually, gradually split by the expansion of the
wood cylinder into ridges or scales, in characteristic fashion for each
species, and is, usually, eventually worn away or otherwise lost, in large
part, from the surface of the tree.

4. The epidermis consists of a single layer of close-fitting, tabular cells
with thick, outer walls. It is impervious to water but lasts in most
trees only during the first year or two, and is best seen on the surfaces
of young stems or twigs. In smooth-barked trees, it may live many
years.

- Cross Section

Radial Cuf

FIG. 24. — C, Cross surface. R, Radial surface. T7, Tangential surface.

Three Surfaces of Wood. — The appearance or " grain " of wood
is influenced by the way in which it is cut. There are three funda-
mental surfaces or exposures. They are as follows: (1) Cross
surfaces in which the markings appear as circles. This is shown
on the surface C. (2) Radial surfaces in which the yearly rings
are cut directly across and appear as lines, as on the surface R.
(3) Tangential surfaces in which the surface is cut parallel to
the annual rings. Characteristic tangential figures are shown on
the surface T.

Logs are sometimes quartered and then cut across the yearly
rings. These "quarter-sawn" pieces are stronger and better

40

ORGANIC STRUCTURAL MATERIALS

than other pieces, but are more costly because of the extra labor
and the waste. Edge-grained, vertical-grained, straight-grained,
and rift-grained pieces are the same as quartered pieces when
these names are applied to manufactured woods. The pith-rays
of some woods are exposed by quartering;
" quarter-sawn " oak is attractive for this
reason.

The best effects in grain or figure are
sometimes obtained when pieces are de-
veloped by what is known as the " rotary
cut." This is often the case with the wood
of the birdseye maple. A revolving log of
the wood that is to be cut is advanced
against a tool that pares a broad, thin
ribbon from its surface. The ribbons are later used as veneers.

FIG. 25. — One method
of quarter-sawing.

s —

It should be noted that grain and figure differ in different pieces of the
same species. One Hard Maple tree (Acer saccharum) may yield char-
acterless pieces that are suitable for little else than flooring, while
another nearby tree of the same species may contain beautiful birdseye
or curly maple, suitable for costly cabinet work.

Ordinary planks and boards are cut parallel to the diameters
of the logs. Grain is not regarded in these pieces, which are
used in ordinary construc-
tions. Such pieces are
known as bastard, slash-
cut, or slice-cut boards or
planks. The segments of
bark and sapwood that
are removed from the out-
side of a log are known as
" slabs." The uneven ap-
pearance of the edges of
boards that have been cut
through from one side of
the log to the other is re-
ferred to as "wain." "Edging" refers to the uneven pieces or
edges that are removed when the boards are cut down to
standard widths. Slabs and edging are worked into laths or
are burned as fuel.

DEFECTS. — Defects are of many kinds. The cracks or
separations that radiate from the centers of trees are known as

FIG. 26.— Ordinary method of sawing a
log. S represents slabs; E represents
edging.

ANNUAL DEPOSITS— DEFECTS 41

" heart-shakes " and " star-shakes." The separations between
the yearly layers are known as " cup-shakes." It is assumed
that "cup-shakes" are influenced by the winds, which roll the
trees to and fro, and, for this reason, the pieces in which cup-
shakes occur are referred to as "rolled lumber." Separations

FIG. 27. — Tree rolled by wind.

caused by wind or frost are "wind-shakes" or "frost-shakes"
and the short but comparatively deep cracks that appear in
planks as a result of rapid drying are known as "checks."

Knots are the Result of Branches. — Buds connected with the
pith-cavity at the center appear upon the surface of the trunk.
They extend and eventually develop into branches. The adja-

42 ORGANIC STRUCTURAL MATERIALS

cent wood-elements between the pith-cavity and the surface of
the trunk are disturbed and the result is a knot. Knots may be
prevented by removing the buds while they are small.

Many Names Apply to Results of Diseases.— Wet-rot, dry-rot,
soft-rot, disease, decay, bluing, rust, mildew, canker, bot,
dote, and other terms are all thus employed. The results indi-
cated by aJl of these names are usually due to the presence of
bacteria or fungi. Wood that is lifeless and
brittle as the result of disease is known as
"brashwood," a name that is also applied to
wood that has become lifeless and brittle as
a result of age.

Defects have been described and stand-
ardized by manufacturers and others, and
lumber is now classified and sold upon the
basis of accepted specifications. Such speci-
fications have been prepared by the Hard-

FIG. 28. — Distortion wood Manufacturers' Association of the
[by branch. United ^^ the padfic Co^ Lumber

Manufacturers' Association, the Yellow Pine Manufacturers'
Association, and others. The principal series of specifications
have been listed and published under one cover by the National
Government.1 Standards have also been prepared by the
American Society for Testing Materials and by the American
Railway Engineering Association.

A Committee appointed by the American Society for Testing Mate-
rials, has defined the several kinds of knots that appear in structural
timber as follows (see Year Book, 1910) :

1. Sound Knot. — A sound knot is one which is solid across its face
and which is as hard as the wood surrounding it; it may be either red
or black, and is so fixed by growth or position that it will retain its place
in the piece.

2. Loose Knot. — A loose knot is one not firmly held in place by growth
or position.

3. Pith Knot. — A pith knot is a sound knot with a pith hole not more
than one-fourth inch in diameter in the center.

4. Encased Knot. — An encased knot is one which is surrounded wholly
or in part by bark or pitch. Where the encasement is less than one-

1 "Rules and Specifications for the Grading of Lumber Adopted by the
Various Manufacturing Associations of the United States" (United States
Forest Service Bulletin, No. 71).

PLATE IV. INFLUENCE OF WIND UPON TREES AT TIMBER LINE

ANNUAL DEPOSITS— DEFECTS 43

eighth inch in width on both sides, not exceeding one-half the circum-
ference of the knot, it shall be considered a sound knot.

5. Rotten Knot. — A rotten knot is one not as hard as the wood it is in.

6. Pin Knot. — A pin knot is a sound knot not over one-half inch in
diameter.

7. Standard Knot. — A standard knot is a sound knot not over one
and one-half inches in diameter.

8. Large Knot. — A large knot is a sound knot, more than one and
one-half inches in diameter.

9. Round Knot. — A round knot is one which is oval or circular in form.

10. Spike Knot. — A spike knot is one sawn in a lengthwise direction;
the mean or average width shall be considered in measuring spike knots.

All banded woods, and the trees that yield them are divided
as follows:

1. The Coniferous Series (Coniferce). — The terms softwoods,
needleleaf and evergreen woods, which are so often used in con-
nection with the woods of this series, are convenient but some-
times inaccurate. These names are unsatisfactory; first, because
some of the woods are actually very hard; second, because the
leaves of some are broader than the name " needleleaf" would
indicate; and third, because the leaves of some drop away every
year and are not evergreen as this term is understood. The name
" conifer" which is best, includes, among others, the pines,
spruces, firs, hemlocks and cedars.

2. The Broadleaf Series (Dicotyledons) . — These woods are
often incorrectly called hardwoods and deciduous woods. The
first of these terms is incorrect, because some of the woods are
very soft; the second fails because the leaves of some of the trees
are persistent or evergreen, rather than deciduous. The leaves,
with netted veins, are comparatively broad, and the name
"broadleaf" is, on the whole, the best of the popular names.
This series includes, among others, the oaks, elms, maples,
hickorys and birches.

CHAPTER V

BANDED TRUNKS AND WOODS (CONTINUED)
CONIFEROUS OR NEEDLELEAF SERIES

Conifers

Coniferous trees cover large areas in parts of Canada and the
United States. The Pines, Spruces, Hemlocks, and other so-
called softwoods are of this group.

Coniferous woods are comparatively light in weight and the
arrangements of the wood-element is, on the whole, simpler than
in the woods of the broadleaf series. The vertical fabric is made
up almost entirely of tracheids. The preponderance of tracheids
and the absence of true vessels are characteristic of these woods
which, because of the simpler arrangement of the wood-elements,
are comparatively easy to work. Coniferous woods are pre-
ferred where the demand is for bulk and strength rather than fine
qualities, and the total requirement as to amount exceeds the
requirement for woods of the broadleaf series. The trunks of
many species yield very large, straight pieces.

The leaves of the coniferous trees are resinous and usually
needlelike and evergreen. The seeds are exposed on the inner
surfaces of woody scales arranged, overlapping one another, in
what are known as cones. As already stated, the names
" softwood" and " evergreen" do not always apply so that the
name " conifer" should be preferred.

44

PINE

Pinus

These woods, which were formerly plentiful in the districts
where the demands of construction were the greatest, have been
more used in carpentry and construction than any others. They
are to the coniferous woods what oaks are to the broadleaf woods;
and, in this country, they yet stand to all woods somewhat as iron
does to all metals. The pines are prized because of qualities,
such as strength, elasticity, light weight and working qualities,
that fit them for the constructions that require the largest quan-
tities of wood.1

Pine trees have straight, solid trunks, which, when grown in
forests, are usually free from branches for many feet up from the
ground. They mature slowly and it is probable that, ultimately,
some species will survive only as cultivated trees.

The needle-shaped, evergreen leaves, which are from one inch
to fifteen or more inches in length, occur singly or in clusters
of two, three, and five. Thirty-six of the known species grow
naturally in the United States. The Dantzic or Northern Pine
(Pinus sylvestris) is an important European species. Pines are
often divided into "soft pines" and "hard pines."

Soft Pines. — The woods that form this group are soft,
light, rather weak, clean, uniform, easily worked, and compara-
tively free from knots and resin. The yearly bands are less
pronounced than in the hard pines. Many resin-ducts, that
are often plainly visible without the microscope, are distributed
over the sections. The Soft Pines may be divided according
to their sources into White Pine (Pinus strobus) on the one hand,
and Sugar Pine (Pinus lambertiana) with some minor species on
the other hand.

White Pine (Pinus strobus}. This tree, formerly the principal eco-
nomic tree of North America, grows in the northern, central, and eastern
portions of the United States. It formed the basis of the early forest
resources of Maine and Michigan, and methods devised to cut and trans-

1 See also "Uses of Commercial Woods of United States: 2, Pines" (United
States Forest Service, Bulletin No. 99, 1911).

45

46 ORGANIC STRUCTURAL MATERIALS

fer the logs have influenced logging practices in all subsequently devel-
oped fields. White Pine was once the only soft wood seriously consid-
ered by lumbermen in the north, and, until as late as the beginning of
the present century, it supplied about thirty per cent, of all the lumber
that was used in this country.1 No other wood known to man has been
more valuable. There are no perfect substitutes, although sugar pine,
spruce, fir, redwood, and even whitewood are used in its stead.

Sugar Pine (Pinus lambertiana) . These trees grow at high elevations
in parts of Oregon and California. The soft, coarse, clean wood can
be used in place of true White Pine. Some of the trees are very large.
Other minor American sources and localities are as follows: White Pine
(P. flexilis), Rocky Mountain Region; White or Silver Pine (P. monti-
cola), Pacific Coast Region; Whitebark Pine (P. albicaulis}, Pacific Coast
Region; Mexican White Pine (P. strobiformis) , Arizona into Mexico;
Parry's Pine (P. quadrifolia), Southern California; Nut Pine (P.cem-
broides), Arizona into Mexico.

Hard Pines. — These differ from soft pines in that they are
harder, stronger, heavier, more resinous, of a deeper color, and
more difficult to work. The yearly bands are pronounced.
Large-sized pieces of Hard Pine can be obtained. The principal
supplies are obtained from the Longleaf Pine (Pinus palustris),
the Shortleaf Pine (Pinus echinata), the Cuban Pine (Pinus
heterophylla) , and the Loblolly Pine (Pinus tceda).

Longleaf Pine (Pinus palustris). This is the principal tree of the
Hard Pine group. The wood, which is the strongest native construc-
tion wood obtainable in large-sized pieces in the United States, is used
in docks, trestles, and other heavy constructions. The trees yield tur-
pentine, tar, and resin. They are usually tapped a few times and are
then felled and cut up into lumber.

The woods of the Cuban, Shortleaf, and Loblolly Pines are so nearly
like that of the Longleaf Pine, that it is often hard to tell them from
that wood or from one another. Either, or all of these woods may thus
be delivered in response to a demand for Southern Hard Pine. It
should be noted, however, that pieces of Southern Hard Pine may now
be graded without difficulty by means of the so-called Density Rule2;
and the results obtained by following this practical rule show that the
strength of pieces of Longleaf, Shortleaf, Loblolly, and other kinds of
Southern Hard Pine depend less upon distinctions due to species than
upon relative densities of individual pieces.

1Roth (United States Forestry Bulletin No. 22, p. 73); "White Pine
Timber Supplies" (United States Senate Doc. 55-1, Vol. IV).
2 See Index "Density Rules."

CONIFEROUS TRUNKS AND WOODS

47

Much of the "Hard Pine" used on the Pacific Coast is derived from
the Douglas Spruce or "Oregon Pine" (Pseudotsuga taxifolia). The
species of pine may be distinguished from one another by differences
that exist between their leaves and cones. These are as follows:1

Names

Leaves

Cones

Number in
cluster

Length

Diameter
(open)

Length

Longleaf pine (P. palustris) . .
Cuban Pine (P. heterophylla)
Shortleaf Pine (P. echinata)..
Loblolly Pine (P. taeda)

2 or 3
2 or 3
2 or 3
3

10 to 15 in.
8 to 12 in.
2 to 5 in.
5 to 10 in.

4 to 5 in.
3 to 5 in.
1 to 2 in.
2 to 3 in.

6 to 10 in.
4 to 7 in.
2 in.
3 to 4 in.

Tar, turpentine, and resin, which are included in what are known as
" naval stores," are derived principally from the Longleaf and Cuban
Pine trees. The quantities of naval stores that are contained in these
trees vary with individuals. From five to twenty per cent, of the dry
weight of the heartwood may be due to resin. There is less resin in
sap wood. The resin in pine is known as rosin.

An exhaustive investigation2 has proved that strength, weight, and
shrinkage are not influenced by "bleeding," and that "bled" lumber is
as good as lumber that has not been "bled." The Louisville & Nash-
ville Railroad once specified "unbled" lumber. Some bled pieces were
included by error. The mill offered to take them back again if they
could be separated from the others. This proved to be impossible and
the matter was dropped.

Confusion exists in regard to the names of the pines. All
Southern Pines are known commercially as Yellow Pines. Ameri-
can White Pine is known as Yellow Pine in Europe, where all
Hard Pines are often referred to as Pitch Pines. Spruce Pine,
Bull Pine, and Bastard Pine are names frequently used to hide
ignorance. The species palustris has thirty local names. Botan-
ical names should be used to designate these as well as other
trees.

1 See also "Timber Pines of the Southern United States" (United States
Forest Service, Bulletin No. 13, 1897); "Properties and Uses of the Southern
Pines" (United States Forest Service, Circular No. 164, 1909); "Relation of
Light Chipping to the Commercial Yield of Naval Stores," Herty (United
States Forest Service, Bulletin No. 90, 1911); "The Naval Stores Industry,"
Schorger and Betts (United States Department of Agriculture, Bulletin
No. 229); etc.

2 United States Bureau of Forestry, Bulletins No. 8 and No. 10.

48 ORGANIC STRUCTURAL MATERIALS

White Pine. Pinus strobus Linn

NOMENCLATURE (Sudworth). Soft Pine (Pa.).

White Pine (local and common Northern Pine (N. C.).

name). Spruce Pine (Tenn.).

Weymouth Pine (Mass., S. C.). Pumpkin Pine.

Patternmaker's Pine.
LOCALITIES.

North-central and northeastern United States, northward into Canada;
southward along the coast to New Jersey, and along the Alleghenies
into Georgia; also Illinois.

FEATURES OF TREE.

Seventy-five to one hundred and fifty feet in height; three to six feet in
diameter; sometimes larger; erect impressive form; tufts of five,
slender, evergreen leaves in long sheaths; cones four to six inches long,
one inch thick, slightly curved; the cone-scales are without prickles.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood cream white; sapwood nearly white; close, straight grain;
compact structure; comparatively free from knots and resin.

STRUCTURAL QUALITIES OF WOOD.

Soft and uniform; seasons well, is easy to work, nails without splitting,
and is quite durable in exposed positions ; one of the lightest and weakest
of eastern United States pines; shrinks, swells and warps less than
other pines; receives paints well.

REPRESENTATIVE USES OF WOOD.
Carpentry, construction, matches, spars, boxes, and numerous other uses

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
24 (United States Forestry Division).1
24.

MODULUS OF ELASTICITY.

1,390,000 (average of 130 tests by United States Forestry Division).1
1,210,000.

MODULUS OF RUPTURE.

7,900 (average of 120 tests by United States Forestry Division,)1
8,900.

REMARKS.

Formerly the chief lumber tree of the United States. The stand "is
rapidly diminishing. Besides its natural enemy the lumberman, the
White Pine is seriously threatened by a disease known as the "White Pine
Blister Rust."

lSee p. 33. See also "The White Pine," Spaulding (United States
Forestry Bulletin No. 22); "White Pine — a Study," Pinchot (Century Com-
pany); "White Pine Timber Supplies" (United States Document No. 40,
Senate, 551, Vol. IV); "White Pine," Pinchot (United States Forest Serv-
ice, Circular No. 67, 1907), "The White Pine," Detwiler (American For-
estry, July, 1916).

CONIFEROUS TRUNKS AND WOODS 49

White Pine. Pinus flexilis James

NOMENCLATURE (Sudworth).

White Pine (Cal., Nev., Utah, Bull Pine (Col.).

Col., N. M.). Western and Rocky Mountain White
Pine (Utah, Mont.). Pine (Cal.).

Limber Pine. Limber-twig Pine.

Rocky Mountain Pine. Arizona Flexilis Pine.

LOCALITIES.

Rocky Mountains, Alberta to Texas and southwestern California.

FEATURES OF TREE.

Forty to fifty feet in height; one to three feet in diameter; tufts of five
rather short, rigid leaves in sheaths; the leaves are not more than two
and one-half inches in length; the oval or cylindrical cones are about
four inches in length.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light, clear yellow, turning red upon exposure; sapwood
nearly white; close-grained; compact structure; numerous and con-
spicuous medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Light and soft; saws, planes, nails, and receives paints well; fairly durable;
similar to White Pine (Pinus strobus).

REPRESENTATIVE USES OF WOOD.
Construction. Similar to White Pine (Pinus strobus).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

27.
MODULUS OF ELASTICITY.

960,000.
MODULUS OF RUPTURE.

8,800.
REMARKS.

This tree forms mountain forests of considerable extent.

1 See also "Limber Pine, Pinus flexilis" James (United States Forest Serv-
ice, Silvical Leaflet No. 46, 1909).

50 ORGANIC STRUCTURAL MATERIALS

Sugar Pine. Pinus lambertiana Dougl

NOMENCLATURE (Sud worth).

Sugar Pine (local and common Little or Great Sugar Pine.

name). Gigantic Pine.

Big Pine, Shade Pine (Cal.). White Pine.

LOCALITIES.

Oregon and California. Best at high altitudes (above four thousand feet).

FEATURES OF TREE.

One hundred to occasionally three hundred feet in height; fifteen to some-
times twenty feet in diameter; the finely toothed leaves, in tufts of five,
are about four inches long; the cones are from ten to eighteen inches in
length and contain edible seeds; there are sugar-like exudations; a
great tree; the tallest and largest of all the pines.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood pinkish-brown; sapwood cream-white; coarse, straight-
grained; compact structure; satiny, conspicuous resin-passages.1

STRUCTURAL QUALITIES OF WOOD.

Light, soft and easily worked; resembles White Pine (Pinus strobus). In
fact this is the "White Pine" of the Pacific Coast.

REPRESENTATIVE USES OF WOOD.

Carpentry, interior finish, doors, blinds, sashes, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

22.
MODULUS OF ELASTICITY.

1,120,000.

MODULUS OF RUPTURE.

8,400.
REMARKS.

This is the most impressive tree form of the genus. Some of the Sugar
Pines may be grouped as to size with some Redwoods and other giant
trees. The Sugar Pines grow at high elevations and form extensive
forests. The sugar-like exudations contain a principle known in medi-
cine as "pinite." The Sugar Pine, as well as the White Pine, is subject
to the disease known as "Blister Rust," which bids fair to injure seri-
ously the stands of these trees.

1 "Sugar Pine and Western Yellow Pine in California," Cooper (United
States Forest Service, Bulletin No. 69, p. 25, 1906); "Sugar Pine," Larsen
and Woodbury (United States Argricultural Bulletin, 426, 1916); "The
Sugar Pine," Detwiler (American Forestry, May 1, 1917).

CONIFEROUS TRUNKS AND WOODS 51

White Pine. Pinus monticola Dougl

NOMENCLATURE (Sudworth).

White Pine (Cal., Nev., Ore.). Little Sugar Pine, Soft Pine (Cal.).

Mountain Pine, Finger Gone Pine Western White Pine.

(Cal.). Mountain Weymouth Pine.

Silver Pine.

LOCALITIES.

Montana, Idaho, Pacific States, and British Columbia.

FEATURES OF TREE.

Eighty to one hundred and fifty feet in height; two to three feet in di-
ameter; sometimes larger; foliage resembles, but is denser than that of
White Pine (Pinus strobus)', the stiff, bluish-green needles are about
four inches long; long, smooth cones.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood light brown or red; sapwood nearly white; straight-grained;
compact structure; suggests White Pine (Pinus strobus).

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong.

REPRESENTATIVE USES OF WOOD.
Lumber.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

24.
MODULUS OF ELASTICITY.

1,350,000.
MODULUS OF RUPTURE.

8,600
REMARKS.

Found at elevations of seven thousand to ten thousand feet. Common
and locally used in northern Idaho.

52 ORGANIC STRUCTURAL MATERIALS

Georgia Pine, Hard Pine, Yellow Pine,
Longleaf Pine. Pinus palustris Mill

NOMENCLATURE (Sudworth).

Turpentine Pine. Florida Pine.

Rosemary Pine. Florida Longleaved Pine.

North Carolina Pitch Pine. Southern Pitch Pine.

Southern Pine. Southern Hard Pine.

Longleaved Yellow Pine. Southern Heart Pine.

Longleaved Pitch Pine. Southern Yellow Pine.

Long Straw Pine. Georgia Pitch Pine.

Pitch Pine. Georgia Longleaved Pine.

Fat Pine. Georgia Heart Pine.

Heart Pine. Georgia Yellow Pine.

Brown Pine. Texas Yellow Pine.

Florida Yellow Pine. Texas Longleaved Pine.

LOCALITIES.

South Atlantic and Gulf States, Virginia to Florida, intermittently.
FEATURES OF TREE.

Fifty to one hundred and twenty feet in height; one to three feet in di-
ameter; tufts of three leaves, ten to fifteen inches long, in long sheaths;
the cones are usually at the ends of the small branches; the cone-scales
have stout, recurved prickles.1
COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood orange; sapwood lighter; compact structure; conspicuous
medullary rays; fine and even appearance in cross-section; quite uni-
form; narrow annual rings (twenty or twenty-five per inch); wide sap-
wood in young trees.1
STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, tough, elastic, durable, and resinous; the strongest and

stiffest of Pines.1
REPRESENTATIVE USES OF WOOD.

Heavy constructions, ship-building, cars, docks, beams, ties, flooring,

house-trim, and many other uses.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
38 (United States Division of Forestry).2
43.

MODULUS OF ELASTICITY.

2,070,000 (average of 1,230 tests by United States Forestry Division).2
2,110,000.
MODULUS OF RUPTURE.

12,600 (average of 1,160 tests by United States Forestry Division).2
16,300.
REMARKS.

One of the best woods for car-building. One of the principal lumber trees
of the Southeast.

1 American Forestry (September, 1915).

2 See p. 33.

CONIFEROUS TRUNKS AND WOODS 53

Cuban Pine. Pinus caribcea Morelet; Pinus

heterophylla (Ell.) Sudivorth

NOMENCLATURE (Sudworth).

Cuban Pine, Slash Pine (local Swamp Pine (Fla., Miss.).

and common names). Bastard Pine, Meadow Pine, Spruce

Pitch Pine, She Pine, She Pitch Pine.

Pine (Ga.} Fla.).

LOCALITIES.

Coast region, North Carolina to Florida, westward to Louisiana; also
Bahamas and Western Cuba.

FEATURES OP TREE.

Fifty to eighty feet in height; one to two feet in diameter; the leaves,
which are ten to fifteen inches long, are gathered in tufts of two and
three; the laterally attached cones are four or five inches long, and
have short, recurved prickles.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Resembles Loblolly Pine wood; the color is dark straw, with tinge of
flesh color; variable and coarse appearance in cross-section; annual
rings are usually wide (ten or twenty per inch).

STRUCTURAL QUALITIES OF WOOD.

Similar to those of Longleaf Pine and of selected pieces of Loblolly Pine
(Pinus tceda); sometimes more resinous than Longleaf Pine (Pinus
palustris).

REPRESENTATIVE USES OF WOOD.

Similar to those of Longleaf Pine, from which it is seldom separated.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
39 (United States Forestry Division).1

MODULUS OF ELASTICITY.
2,370,000 (average of 410 tests of United States Division of Forestry).1

MODULUS OF RUPTURE.

13,600 (average of 410 tests by United States Division of Forestry).1

REMARKS.

This wood resembles and is marketed with Longleaf Pine (Pinus palustris),
and also resembles Loblolly Pine (Pinus tceda). Cuban Pine trees repro-
duce rapidly and are often large enough to yield pitch and turpentine
when they are forty years of age. This is important, since the species
from which most "naval stores" are obtained are being destroyed so
rapidly. The Cuban Pine grows in Honduras and Cuba, as well as in
the sub-tropical regions of the United States. This explains why it is
called the Cuban Pine.

1 See p. 33.

54 ORGANIC STRUCTURAL MATERIALS

Shortleaf Pine, Yellow Pine. Pinus echinata Mill; Pinus

mitis Michx
NOMENCLATURE (Sud worth).

Common Yellow Pine, Hard Rosemary Pine (N. C.).

Pine. Virginia Yellow Pine.

Spruce Pine (Del., Miss., Ark.). North Carolina Yellow Pine.

Bull Pine (Va.). North Carolina Pine.

Shortshat Pine (Del.). Carolina Pine.

Pitch Pine (Mo.). Slash Pine.

Poor Pine (Fla.). Old Field Pine.

Shortleaved Yellow Pine (N. C.).

LOCALITIES.

Staten Island to Florida; westward intermittently to Illinois, Kansas,
and Texas.

FEATURE OP TREE.

Sixty to sometimes ninety feet in height; two to sometimes four feet in
diameter; a large, erect tree; small, lateral cones have minute, weak
prickles; the leaves are about four and one-half inches long; they are
usually gathered in groups of two; the sheaths are long.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Resembles Longleaf and Loblolly Pines; variable appearance in cross-
section; wide annual rings near heart.

STRUCTURAL QUALITIES OF WOOD.

Variable, usually hard, tough, strong, durable, and resinous; lighter than
Longleaf and Loblolly Pines.

REPRESENTATIVE USES OF WOOD.
Lumber and construction; similar to Longleaf Pine (Pinus palustris).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
32 (United States Forestry Division).1
30.

MODULUS OF ELASTICITY.

1,680,000 (average of 330 tests by United States Forestry Division).1
1,950,000.

MODULUS OF RUPTURE.

10,100 (average of 330 tests by United States Forestry Division).1
14,700.

REMARKS.

The Shortleaf Pine yields considerable pitch and turpentine, and is the
principal species of northern Arkansas, Kansas, and Missouri. 2

iSeep. 33.

2 "Southern Pine," Mohr (United States Forestry Circular No. 12);
''Timber Pines of Southern States," Mohr (United States Forestry Bulletin
No. 13); "Shortleaf Pine," Mattoon (United States Department Agriculture
Bulletin, 308, 1915) ; "The Shortleaf Pine," Detwiler (American Forestry,
September, 1916).

CONIFEROUS TRUNKS AND WOODS 55

Loblolly Pine. Pinus tceda Linn

NOMENCLATURE (Sudworth).

Old Field Pine. Sap Pine.

Torch Pine. Meadow Pine.

Rosemary Pine. Cornstalk Pine (Va.).

Slash Pine. Black Pine.

Longschat Pine. Foxtail Pine.

Longshucks. Indian Pine.

Black Slash Pine. Spruce Pine.

Frankincense Pine. Bastard Pine.

Shortleaf Pine. Yellow Pine.

Bull Pine. Swamp Pine.

Virginia Pine. Longstraw Pine.

North Carolina Pine.
LOCALITIES.

Southern New Jersey to Florida; westward intermittently to Texas.

FEATURES OF TREE.

Fifty to one hundred or more feet in height; two to sometimes four feet
in thickness; leaves in groups of threes are about six inches long; scales
of lateral cones have short, straight spines; a large tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Resembles Longleaf Pine (Pinus palustris}, but is variable; coarse cross-
sections; very wide annual rings (three to twelve per inch).

STRUCTURAL QUALITIES OF WOOD.

Resembles Shortleaf Pine (Pinus echinata)', selected pieces rank with
Longleaf Pine (Pinus palustris).1

REPRESENTATIVE USES OF WOOD.

Used with other Southern pines; inferior in uniformity, strength, and
durability.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
33 (United States Forestry Division).2
33.

MODULUS OF ELASTICITY.

2,050,000 (average of 660 tests by United States Forestry Division).2
1,600,000.

MODULUS OF RUPTURE.

11,300 (average of 650 tests by United States Forestry Division).2
12,500.

REMARKS.

These trees grow naturally on deforested land, whence the name of Old
Field Pine. A source of abundant and cheap material. A vigorous,
prolific grower, probably one of the pines of the future.

1 "Loblolly Pine in eastern Texas," Zon (United States Forest Service,
Bulletin No. 64, 1905).

2 See p. 33.

56 ORGANIC STRUCTURAL MATERIALS

Bull Pine, Yellow Pine, Western
Yellow Pine. Pinus ponderosa Laws

NOMENCLATURE (Sudworth).

Big Pine. Heavy-wooded Pine.

Longleaved Pine. Western Pitch Pine.

Red Pine. Heavy Pine (Cal.).

Pitch Pine. Foothills Yellow Pine.

Southern Yellow Pine. Montana Black Pine.

LOCALITIES

Rocky Mountains; westward intermittently to Pacific Ocean; always at
elevations of eighteen hundred or more feet.

FEATURES OF TREE.

One hundred to sometimes three hundred feet in height; six to sometimes
twelve feet in diameter; thick, deeply furrowed bark; the leaves, which
are in tufts of twos and threes, are from five to nine inches long; the
conical cones are at the ends of small branches; the scales are tipped with
prickles.1

COLOR, APPEARANCE, OR GRAIN OF WOOD.

The thin heartwbod is light red; sapwood nearly white; rather coarse
grain; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Variable, heavy, hard, strong, and brittle; not durable.

REPRESENTATIVE USES OF WOOD.
Lumber, railway ties, mine-timbers, fuel, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

29.
MODULUS OF ELASTICITY.

1,260,000.
MODULUS OP RUPTURE.

10,200.
REMARKS.

These trees are often killed by tree-boring beetles (Dendroctonus ponder-
osa), and the wood of trees thus attacked eventually assumes a bright
blue color (see also von Schrenk, United States Bureau of Plant In-
dustry, Bulletin No. 36). The specific name ponderosa was given
because of the great size of the trees.

1 "Western Yellow Pine in Arizona and New Mexico," Woolsey (United
States Forest Service, Bulletin No. 101, 1911). "Western Yellow Pine
in Oregon," Munger (United States Department of Agriculture, Bulletin
No. 418, 1917).

CONIFEROUS TRUNKS AND WOODS 57

Norway Pine, Red Pine. Pinus resinosa Ait

NOMENCLATURE (Sudworth).

Norway Pine, Red Pine (local and Hard Pine (Wis.).
common names). Canadian Red Pine (Eng.).

LOCALITIES.

Southern Canada, northern United States from Maine to Minnesota;
Pennsylvania.

FEATURES OF TREE.

Sixty to ninety feet in height; one to three feet in diameter; reddish bark
on branchlets; leaves are in twos from long sheaths; the cones are at
the ends of the branches; the scales are not prickle-tipped; a tall,
straight tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

The thin heartwood is light red; sapwood yellow to white; numerous pro-
nounced medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Light, hard, elastic, not durable, and resinous.

REPRESENTATIVE USES OF WOOD.

Piles, telegraph poles, masts, flooring, and wainscoting.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
31 (United States Forestry Division).1
30.

MODULUS OF ELASTICITY.

1,620,000 (average of 100 tests by United States Forestry Division).1
1,600,000

MODULUS OF RUPTURE.

9,100 (average of 95 tests by United States Forestry Division).1
12.500.

REMARKS.

In spite of the specific name resinosa, which signifies resinous, these trees
yield unimportant quantities of turpentine and resin.2

1 See p. 33.

2 "Red or Norway Pine, Pinus resinosa Ait," (United States Forest
Service, Silvical Leaflet No. 43, 1909); "Norway Pine in the Lake States,"
Woolsey (United States Department of Agriculture, Bulletin No. 139, 1914).

58 ORGANIC STRUCTURAL MATERIALS

Pitch Pine. Pinus rigida Mill

NOMENCLATURE (Sud worth).

PitchPine (local and common name) Yellow Pine (Pa.).

Longleaved Pine, Longschat Pine Black Pine (N. C.).

(Del.). Black Norway Pine.

Hard Pine (Mass.). Rigid Pine, Sap Pine.

LOCALITIES.

New Brunswick to Ontario and Ohio, southward to northern Georgia and
Alabama; the predominant tree of the New Jersey " pine-barrens."

FEATURES OP TREE.

Forty to sometimes eighty feet in height; one to sometimes three feet
in diameter; the rigid, flattened leaves, which are three and one-half to
five inches long, are in groups of threes; the sheaths are short; the cones
are compact; the reddish scales have stout, recurved prickles.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown or red; thick sapwood yellow to nearly white;
coarse, conspicuous grain; compact structure; very resinous.

STRUCTURAL QUALITIES OP WOOD.
Light, soft, not strong, and brittle.

REPRESENTATIVE USES OP WOOD.
Coarse lumber, fuel, and charcoal.

WEIGHT OP SEASONED WOOD IN POUNDS PER CUBIC FOOT.

32.
MODULUS OP ELASTICITY.

820,000.
MODULUS OF RUPTURE.

10,500.
REMARKS.

In North America the name, "Pitch Pine" is sometimes misleadingly used
to include all Hard Pines ; abroad, it is sometimes made to include White
Pine. So much resin is present that Pitch Pine is not greatly valued in
construction. In spite of this fact, the trees are not relied upon for
naval stores. The trees are hardy. They sometimes grow on rocks
or on sand near the ocean where they survive in spite of occasional
inundations.

CONIFEROUS TRUNKS AND WOODS 59

Northern Pine, Scotch Pine, D . , . T .

_ . . _. Pinus sylvestns Linn

Dantzic Pine.

NOMENCLATUKE.

Dantzic Fir (from place of ship- Swedish Fir.

ment). Scots or Scottish Fir.

Rigi Fir (from place of shipment). Northern Fir.

Memel Fir (from place of shipment). Redwood, Yellow-wood.

Stettin Fir (from place of ship- Deal (local).

ment).

LOCALITIES.

Widespread in Europe, as Scotland, Germany, and Russia; also Asia.
r. Cultivated in the United States.

FEATURES OF TREE.

Fifty to one hundred feet in height; two to five feet in diameter; sometimes
larger; the leaves, which are about four inches in length, are slightly
twisted, and are gathered in tufts of twos and threes; the cones are at
the ends of the small branches; the scales are not prickle-tipped.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood reddish white to yellowish white; sapwood similar; even,
straight grain (varies with locality).

STRUCTURAL QUALITIES OF WOOD.

Moderately light, hard, tough, and elastic; easily worked (varies with
locality).

REPRESENTATIVE USES OF WOOD.
Carpentry, construction, planks, beams, masts, and heavy timber.1

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
34 (Laslett) (varies with locality).

MODULUS OF ELASTICITY.

1,680,000 (Laslett) (varies with locality).
1,800,000 (Thurston).

MODULUS OF RUPTURE.
7,000 (Thurston) (varies with locality).

REMARKS.

This is the principal softwood produced by the forests of Europe. The
trees are widely distributed. The Dantzic and Rigi forests produce the
best wood. Wood "equal to Dantzic Fir" is sometimes specified. The
wood suggests true White Pine (Pinus strobus).

1 "Scotch Pine" (Pinus sylvestris), Pinchot (United States Forest Service,
Circular No. 68, 1907).

60 ORGANIC STRUCTURAL MATERIALS

The Stone Pine (Pinus cembra,) which is said to be best de-
veloped in Switzerland, yields a smooth, fine-grained wood which
suggests true White Pine. This wood is often seen in carvings.

The Bhotan Pine (Pinus excelsa) of the Himalayas closely re-
sembles the White Pine tree in size and habit, and yields a wood
which is very similar to White Pine.

The Lodgepole Pine (Pinus murrayana) also called the Tamarack,
Tamarack Pine, Murray Pine, Prickly Spruce, Black Spruce, and White
Spruce, grows from Alaska to California and New Mexico. Trees often
grow at altitudes of six to eleven thousand feet. The remarkably tall,
slender trunks can be made into ties, posts, and poles. The light,
straight-grained woods are hard to season, but easy to work. Trees
are sensitive to fires, but these fires do not normally kill the seeds (see
also Erickson, "Forestry and Irrigation," p. 503, 1904; "The Lodgepole
Pine," Ziegler, U. S. Forest Service Circular No. 126; "Utilization and
Management of Lodgepole Pine in the Rocky Mountains," Mason.
United States Department of Agriculture, Bulletin No. 234, 1915;
etc.).

The Spruce Pine (Pinus glabra) is the least common of the lower
southern states pines. It seldom forms pure forests and is of relatively
small commercial importance. The wood resembles that of the Lob-
lolly Pine. The name Spruce Pine is popularly applied to trees of ten
other American species (Sudworth). Two of these are not pines.

The Pond Pine (Pinus serotina). — This is the Marsh Pine of the woods-
man. The wood is seldom distinguished at the mills where it furnishes
much of the lumber known as North Carolina Pine. Pond pine trees
grow along the Atlantic coast from Albermarle Sound south to Florida.
The six-inch or eight-inch leaves are in tufts of three. The cones some-
times remain on the trees for several years. The trees are now bled for
turpentine. The Pond Pine is also known as the Meadow, Loblolly,
Spruce, Bastard and Bull Pine (see also Roth, U. S. Forestry Bulletin
No. 13).

The Monterey Pine (Pinus radiata). — This tree grows best near
Monterey, California. It is often one hundred feet high and is sym-
metrical or distorted, according to its exposure. Monterey pine trees
are widely transplanted for landscape effects, and the trunks are occa-
sionally cut into lumber.

The Digger, Grayleaf, Gray or Sabine Pine (Pinus sabiniana) of
western California affords a poor and seldom-used wood. The nuts
were prized by Digger Indians, whence the name. The tree forms are
unusual. The trunks are divided and the sparse, grayish foliage is more
or less concentrated near the ends of the branches. The Digger Pine
yields a turpentine (abietene) that is used in medicine.

The Scrub Pine or Jack Pine (Pinus divaricata) of the north-central
and Atlantic states, yields a wood that is sometimes classed among the

CONIFEROUS TRUNKS AND WOODS 61

lighter Hard Pines and that is used for ties and fuel. The species is
hardy in some semi-arid regions where other pines will not grow.

The Scrub Pine or Jersey Pine (Pinus virginiana) grows from Staten
Island, southward and westward into Alabama and Tennessee. The
inferior wood is used for fuel, water-pipes, and coarse lumber. l

lSee also "Scrub Pine" (Pinus virginiana), (United States Forest Service,
Bulletin No. 94, 19 ID.

KAURI PINE

Dammara

The Kauri Pine grows in New Zealand and yields a strong
light, durable, and elastic wood. The tough, leather-like leaves
suggest those of the Box.

The reputation of the species depends principally upon a resin
which is much used in the manufacture of high-grade varnishes.
This resin unites with linseed oil more perfectly and at lower
temperatures, than most other varnish resins, and has sold for
more than one thousand dollars a ton. The best Kauri, known
as " fossil resin," is obtained by digging over areas from which
the trees have disappeared. These deposits exist a few feet
below the surface and yield pieces that commonly vary in size
from small pebbles to lumps as large as eggs. One exceptional
mass, weighing two hundred and twenty pounds, has been
reported.1 There are also "semi-fossil" and " fresh-product"
resins. The fresh exudations from Kauri Pine trees resemble the
product known as Venice turpentine.

Varnish resins may be roughly divided according to the manner in
which they unite with oil and with spirit. In the first case, oil becomes
part of the whole, whereas, in the second case, spirits simply dissolve
the ingredients and then evaporate from them. As noted, Kauri resin
is one of the best of the oil-varnish resins, and, in a similar way, shellac
is among the valuable spirit- varnish resins.

Gums and resins should be distinguished from one another. A true
gum usually dissolves in water, while a true resin usually yields to oil
or spirit. A solution of gum and water forms a mucilage. The name
gum is often applied for convenience to substances that are actually
resins.

1 "Notes on Fossil Resins," R. Ingham Clark (published by C. Letts &
Company, London).

62

CONIFEROUS TRUNKS AND WOODS 63

. Dammara australis Lambert

Agathis australis Salisbury

OMENCLATURE.

Kauri Pine (local and general). Cowdie Pine (New Zealand and

many localities).

LOCALITIES.
New Zealand.

FEATURES OF TREE.

Ninety to one hundred feet in height; three to four feet in diameter;
occasional specimens much larger; a tall, handsome tree; the willow-
like leaves are from two to three and one-half inches long, and from
one-half to three-fourths of an inch in breadth; the cones are about
two and one-half inches in diameter; the resin is characteristic.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood straw-colored ; fine, straight grain, with silky luster suggesting
Satinwood; "mottled Kauri" is separated and used for cabinet work.

STRUCTURAL QUALITIES OF WOOD.

Moderately hard, light, elastic, and strong; it seasons well, works readily,
and receives a high polish; it is quite free from knots; it stands well,
wears evenly, and has an agreeable odor.

REPRESENTATIVE USES OF WOOD.
Carpentry and masts.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
33 (Laslett) varies with locality.

MODULUS OF ELASTICITY.
1,810,000 (Laslett).

MODULUS OF RUPTURE.

REMARKS.

The species is widely known by its resin. The most valuable forest
tree of New Zealand.

SPRUCE

Picea

Spruce trees form forests in North America and in Europe.
The Norway Spruce, or " White Fir" (Picea excelsa), is the prin-
cipal species in Europe, while the Black Spruce (Picea nigra), the
White Spruce (Picea alba), and the Red Spruce (Picea rubens)
are notable in some parts of the East in the United States. The
White Spruce (Picea engelmanni) is an important species in the
West. In North America spruce trees prefer northern localities
where there are short summers and long winters.

The eastern American species yield soft, clean, light, close-
grained woods that are much valued in constructions. The
Western Spruce yields a valuable wood, but this is less familiar
because of its remoteness from the eastern markets. Spruce
resembles and forms one of the best eastern substitutes for White
Pine. It is also valued for paper pulp.

The eastern product is divided according to appearance, and
irrespective of species, into " White Spruce" and "Black Spruce."
The pieces that have wide annual layers are usually classed as
White Spruce, while those that have narrow layers are classed as
Black Spruce. Spruce woods and Fir woods are often confused
with one another, and there are so-called spruce trees, as "Doug-
las Spruce" and "Kauri Spruce," that are not true spruces.
European Spruce is sometimes known locally as "White Deal."

The insect and fungus enemies of spruce trees have received
much attention.1 The largest and best trees seem most liable
to attack. Hopkins states that the spruce-destroying beetle
(Dendroctonus piceaperda) is accountable for much of the damage
done in the eastern states. This beetle gains entrance to the
tree through crevices in the bark, and then cuts grooves on the
surface of the sensitive outer sap wood. The resins that collect
in these grooves or tunnels are ejected and form what are known
as "pitch tubes." The presence of pitch tubes and particles of
wood on the ground at the base of a tree is evidence that the
tree has been attacked. An intimate connection exists between
the attacks of these and other insects, and those of fungi. The

64

CONIFEROUS TRUNKS AND TREES

65

latter may lodge in and infect wounds caused by the former. It
should be noted that wood may remain sound for sometime
after the physical death of the tree, and that such wood can be
used for lumber and for paper pulp.

" Windfalls" may result from insects, fungi, age, fire, and tornadoes,
or from a combination of these agencies. In windfalls, trees are piled
promiscuously upon one another like giant jackstraws. Trunks and
limbs intermingle and later the mass is often penetrated by wiry, second-
growth saplings. Passage through such a district is made by cautiously
walking backward and forward, up and down over trunks and limbs.
It is sometimes impossible to proceed for more than two or three miles

daily in a straight line through a windfall,
also sometimes used.2

The term "blowdown" is

Spruce trees have single, short, sharp-pointed leaves which are
keeled above and below and which therefore appear four-sided.
Spruce cones hang downward. Spruce trees may be distin-
guished from Pines, Firs, and Hemlocks, by remembering that
pine leaves are longer and grow in clusters, that hemlock leaves
are flat, blunt, and two-ranked, and that the cones of the Fir
tree point upward.

Names

Arrangement of leaves

Shape of leaves

Cones

Pine (Pinus) . . .

In tufts or clusters.

Comparatively long.

Spruce (Picea).

Single, scattered,

Short, sharp ends,

Hang down,

point in all direc-

keeled above and be-

1 to 6 inches

tions.

low. Somewhat

long.

four-sided.

Fir (Abies)

Single, scattered, ap-

Short, blunt ends,

Stand erect,

pear somewhat as in

flat.

2 to 4 inches

tiwo ranks.

long.

Hemlock

Single, scattered, ap-

Short, blunt ends,

Hang down,

(Tsuga).

pear as in two ranks.

flat.

% to 1 inch

long.

1 "Insect Enemies of Spruce in the Northeast" and "Insect Enemies of
the Forest of the Northwest," Hopkins (United States Division Entomology,
Bulletins No. 28 and No. 21); also "Diseases New England Conifers," von
Schrenk (United States Division Vegetable Physiology and Pathology,
Bulletin No. 25.

2 See "Transactions American Institute Mining Engineers," 1899; see
also "Third Annual Report Pennsylvania Department Agriculture."

66 ORGANIC STRUCTURAL MATERIALS

Picea nigra Link

Black Spruce. D. y . ,,.„
Picea manana Mill

NOMENCLATURE (Sudworth).
Spruce (Vt.), Yew Pine, Spruce White Spruce (W. Va.).

Pine (W. Va.). He Balsam (Del., N. C.).

Double Spruce (Me., Vt., Minn.). Water Spruce (Me.).
Blue Spruce (Wis.).

LOCALITIES.

Labrador and Alaska, southward to New York, Pennsylvania, Wisconsin,
and Saskatchewan.

FEATURES OF TREE.

Forty to eighty feet in height; one to two feet in diameter; conical shape,
with straight trunk; four-sided leaves are somewhat narrowed toward
the tips; the leaves are from three-eighths of an inch to five-eighths of
an inch in length; they are lighter on the upper surfaces than on the
lower; cones remain for several years, being thus distinct from those
of the White Spruce (Picea alba).

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish, nearly white; sapwood lighter; straight grain; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, soft, not strong, elastic, and resonant; not durable when exposed.

REPRESENTATIVE USES OF WOOD.

Lumber, flooring, carpentry, ship-building, piles, posts, railway ties,
paddles, oars, "sounding-boards," and paper-pulp.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,560,000.
MODULUS OF RUPTURE.

10,600.
REMARKS.

A substitute for Soft Pine. See also "Black Spruce, Picea mariana
(Mill.)" (United States Forest Service, Silvical Leaflet No. 28, 1908).

The Red Spruce (Picea rubens) is one of the principal lumber trees of
northern New England. This tree, which is much like the Black Spruce,
is from fifty to eighty feet in height, and from two to three feet in diameter.
Large quantities of its light, close-grained, reddish, satiny wood are cut into
lumber or used in the manufacture of paper-pulp.

CONIFEROUS TRUNKS AND WOODS 67

White Spruce. Picea alba Link

Picea canadensis Mill

NOMENCLATURE (Sudworth).

Single Spruce (Me., Vt., Minn.). Skunk Spruce (Wis., New Eng )
Bog Spruce, Cat Spruce (New Eng.). Spruce, Double Spruce (Vt.).

Pine (Hudson Bay).

LOCALITIES.

Northern United States, Canada to Labrador and Alaska.

FEATURES OF TREE.

Fifty to one hundred feet in height; one to two feet in diameter; occa-
sionally larger; compact, symmetrical, conical shape; foliage lighter
than Black Spruce; cones fall sooner than those of Black Spruce;
whitish resin.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light yellow; sapwood similar; straight-grained; numerous
prominent medullary rays; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong (similar to those of Black Spruce (Picea nigra).

REPRESENTATIVE USES OF WOOD.

Lumber, flooring, carpentry, etc. (similar to those of Black Spruce
(Picea nigra).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

25.
MODULUS OF ELASTICITY.

1,450,000.
MODULUS OF RUPTURE.

10,600.
REMARKS.

Notable as resident of high latitudes. One of the chief trees of the
Arctic forests. The wood, used similarly to Black Spruce, is substi-
tuted for White Pine.

It is often difficult to distinguish between Black Spruce trees and those of
the White Spruce. On the whole, the foliage of the former is darker; there
are also differences in the shapes and in the persistence of the cones. The
names " Double Spruce" and "Single Spruce" are without botanical founda-
tion. Woods obtained from these two trees exhibit similar qualities and
are not separated by lumbermen.

68 ORGANIC STRUCTURAL MATERIALS

White Spruce. Picea engelmanni Engelm

NOMENCLATURE (Sudworth).

White Spruce (Ore., Col., Utah, White Pine (Idaho), Mountain

Idaho). Spruce (Mont.).

Balsam, Engelmann's Spruce

(Utah).

LOCALITIES.

British Columbia to Oregon, eastward to Alberta, and south through the
Rocky Mountain region to northern New Mexico and Arizona.

FEATURES OF TREE.

Frequently seventy-five to one hundred feet in height; sometimes one
hundred and fifty feet in height; two to three feet in diameter; sometimes
a low shrub; the straight, slender leaves are from three-fourths of an
inch to one and one-fourth inches in length; they are flexible, with
sharp, thick tips, and they spread in all directions; the elliptical cones
are from one and one-half inches to two and one-half inches long; the
scales are toothed at the apex.1

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood pale reddish yellow; sapwood similar; close, straight grain;
compact structure; conspicuous medullary rays.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong.

REPRESENTATIVE USES OF WOOD.

Lumber, charcoal and fuel; bark rich in tannin is sometimes used for
tanning.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

21.
MODULUS OF ELASTICITY.

1,140,000.
MODULUS OF RUPTURE.

8,100.
REMARKS.

Notable as a resident of high altitudes, extensive forests occurring at
eight to ten thousand feet above sea-level. A valuable tree of the cen-
tral and southern Rocky Mountain regions.

^'Engelmann Spruce in the Rocky Mountain," Hodson and Foster
(United States Forest Service, Circular No. 170); "Engelmanns Spruce"
Pinchot (United States Forest Service, Silvical Leaflet No. 3, 1907).

CONIFEROUS TRUNKS AND WOODS 69

Sitka Spruce. Picea sitchensis Trautv. and Mayer

NOMENCLATURE (Sudworth).

Sitka Spruce (local and common Menzies Spruce,
name). Western Spruce.

Tideland Spruce (Cal., Oreg., Great Tideland Spruce.
Wash.).

LOCALITIES.

Pacific Coast region, Alaska to central California; extends inland about
fifty miles; prefers low elevations.

FEATURES OP TREE.

One hundred and fifty or more feet in height; three feet or more in di-
ameter; the stiff, straight, flat leaves, which are from five-eighths of an
inch to three-fourths of an inch in length, radiate in all directions; the
oval or cylindrical cones are from three to four inches in length; the
bark is scaly and of a reddish-brown color.1

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light reddish brown; sapwood nearly white; coarse-grained;
satiny.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong.

REPRESENTATIVE USES OF WOOD.

Construction, interior finish, fencing, boat-building, and cooperage.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

2,626.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

10,400.
REMARKS.
A giant among the spruces. Forms an extensive coast-belt forest.

1 "Sitka Spruce," Pinchot (United States Forest Service, Silvical Leaflet
No. 6, 1907).

DOUGLAS SPRUCE, DOUGLAS FIR, OREGON PINE

Pseudotsuga.

These trees form almost pure forests in Washington and Ore-
gon. They grow sparingly in Mexico, Texas, and at high alti-
tudes in Colorado. Transplanted specimens have survived in
New York. It should be noted that the Douglas Spruce is
neither Spruce, Fir, or Pine. The generic name is from pseudo
or "false," and tsuga or " Hemlock," and the tree may be regarded
as in the nature of a bastard Hemlock. The species has also
been classed as Pinus taxifolia and Abies taxifolia.1

The durable, strong, light red, or yellow wood, which resembles
larch or true hard pine is used in place of hard pine on the
Pacific Coast. It is one of the general utility woods of that coast.
The trees are among the greatest known to man. Individuals
have reached heights of three hundred and fifty feet,2 and diame-
ters of twelve and even fifteen feet. Logs that yield timbers
two feet square and one hundred feet long are not uncommon.
Single trees have been cut that scaled sixty thousand feet board
measure. The Douglas Spruce grows rapidly. It is hardy, and,
like the redwoods, is likely to resist commercial extinction.

Red and Yellow varieties of Douglas Spruce wood are recog-
nized by lumbermen. The former woods come from younger
trees, and are coarser and less valuable than the latter kinds
which come from the older trees. The wood is also marketed
under the commercial names of Oregon Pine, Hard Pine, Pacific
Pine, Red Spruce, Red Fir, Yellow Fir, etc. The genus includes
one other species, the much less important Big Cone Spruce
(Pseudotsuga macrocarpa) of California, which yields an inferior
wood.

1 Some difficulties associated with the classification of this tree are
enumerated on pages 23 and 24 of Sudworth's Check List.

2 The tallest specimen recorded was three hundred and eighty feet high.
See also "Growth and Management of Douglas Fir in Pacific Northwest,"

Munger (United States Forest Service Circular No. 175, p. 23); "Properties
and Uses of Douglas Fir," Cline and Knap (United States Forest Service
Bulletin No. 88); "Douglas Fir," Frothingham (United States Forest
Service, Circular No. 150, 1909); "Douglas Fir," Detwiler (American
Forestry, February, 1916).

70

CONIFEROUS TRUNKS AND WOODS 71

Pseudotsuga mucronata Sudw.

Douglas Spruce, Douglas Fir. Pseudotsuga taxi/olio, Lam

Pseudotsuga Douglasii Can

NOMENCLATURE (Sudworth).

Oregon Pine (Cal., Wash., Ore.) Douglas-tree, Cork-barked Douglas

Red Fir, Yellow Fir (Ore., Wash., Spruce. (Occasional)

Idaho, Utah, Mont., Col.). Spruce, Fir (Mont.)

Red Pine (Utah, Idaho, Col.). Puget Sound Pine (Wash.).

LOCALITIES.

Pacific Coast region, Mexico to British Columbia; best in Western Ore-
gon and Washington.

FEATURES OF TREE.

One hundred and seventy-five to sometimes three hundred feet in height ;
three to five and sometimes ten feet in diameter; older bark rough-gray,
often looking as though braided. One of the world's greatest trees.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light red to yellow; scant sapwood nearly white; comparatively
free from resins; pronounced variable rings (four to forty per inch).

STRUCTURAL QUALITIES OF WOOD.

Variable, usually hard, and strong; rather difficult to work, durable,
splits easily, can be obtained in large pieces. l

REPRESENTATIVE USES OF WOOD.

Heavy constructions, dimension-timbers, lumber, railway ties, paving
blocks, wood-stave pipes, posts, poles, piles, masts, and fuel. The wood
is used much as hard pine is used.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
32 (United States Forestry Division).2
36 (Average of 20 tests by Soule).3
32.

MODULUS OF ELASTICITY.

1,680,000 (average of 41 tests by United States Forestry Division).2

1,862,000 (average of 21 tests by Soule).3

1,824,000.

MODULUS OF RUPTURE.

7,900 (average of 41 tests by United States Forestry Division).2
9,334 (average of 21 tests by Soule).3
12,500.

REMARKS.

1 See also" Properties and Uses of Douglas Fir: Pt. 1, Mechanical Properties;
Pt. 2, Commercial Uses" (United States Forest Service, Bulletin No. 88,
1911).

2 See p. 33.

3 Professor Frank Soule", University of California, Trans. Am. Inst. M. E.,
Vol. XXIX, p. 552.

FIR

A hies

The Silver Fir (Abies grandis), the Red Fir (Abies magnified],
and the Noble Fir (Abies nobilis), are valued west of the Rocky
Mountains, while the Balsam Fir (Abies balsamea) is of some com-
mercial importance in the East.

Some of the Fir trees in the Western States are so large as to
call for the special methods that are used to fell the giant .speci-
mens of other species. In such cases platforms are erected, far
enough up from the ground, so that axemen, standing upon them,
can" cut through above the hollow or decayed parts that are
common near the surface of the ground. It is also arranged so
that the trees, as they fall, shall strike the ground more or less
uniformly along their sides and thus diminish the danger from
splintering or breaking, which is associated with the impact of
such large trunks.1

Fir and Spruce resemble one another in appearance and struc-
tural qualit'es and are often used in place of one another in the
United States. Fir, Spruce, and Pine are often confused with
one another in Europe.

Fir trees have flat, scattered, evergreen leaves and erect cones.
The Balsam Fir may be distinguished by blisters, abundantly
supplied in the bark of all but the oldest trunks, which contain a
clear, liquid resin known as Canada Balsam.

1 Descriptions of special methods employed in harvesting Douglas Spruce,
Redwoods, Giant Cedars, and other Western species are as follows: Engi-
neering Magazine, Bishop (Vol. XIII, p. 70) ; National Geographic Magazine,
Gannett (Vol. X, No. 5, May, 1899).

72

CONIFEROUS TRUNKS AND WOODS 73

Balsam Fir, Common Balsam Fir. Abies balsamea (L.) Mill.

NOMENCLATURE (Sud worth).

Balsam (Vt., N. H., N. Y.). Blister pine, Fir Pine (W. Va.).

Fir Tree (Vt.). Single Spruce, Silver Pine (Hudson

Balm of Gilead (Del.). Bay).

Canada Balsam (N. C.).

Balm of Gilead Fir.(N. Y., Pa.).

LOCALITIES.

Labrador, southward through the mountains, and westward to Minnesota.

FEATURES OF TREE.

Fifty to seventy feet in height; one to two feet in diameter; sometimes a
low shrub; blisters in smooth bark contain thick balsam; erect cones.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood white to brownish; sap wood lighter; coarse-grained; compact
structure; satiny.

STRUCTURAL QUALITIES OF WOOD.

Soft, light, not durable or strong, resinous, and easily split.

REPRESENTATIVE USES OF WOOD.
Occasionally used as inferior lumber.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

23.
MODULUS OF ELASTICITY.

1,160,000.
MODULUS OF RUPTURE.

7,300.
REMARKS.

These trees grow naturally over Northern pine lands, and yield wood
which is commonly sold with Spruce and Pine. Of all the native coni-
fers this is one of the most difficult trees to cultivate. The thick
fluid-resin, or balsam, known as Canada Balsam, is used in medicine.
It should be noted that the Poplar (Populus balsamifera) is also called
Balm of Gilead. See also "Balsam Fir," Zon (United States Depart-
ment of Agriculture Bulletin No. 55).

74 ORGANIC STRUCTURAL MATERIALS

Great Silver Fir, White Fir. Abies grandis LindL

NOMENCLATURE (Sudworth).

Silver Fir (Mont., Idaho). Yellow Fir (Mont., Idaho)

Oregon White Fir, Western White Lowland Fir.
Fir (Cal.).

LOCALITIES.

Vancouver region, northwestern United States; best in western Washing-
ton and Oregon.

FEATURES OP TREE.

Two hundred to sometimes three hundred feet in height; two to five feet
in diameter; leaves deep green above, silvery below, usually curved;
a handsome tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown; sapwood lighter; coarse-grained; compact
structure.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong.

REPRESENTATIVE USES OF WOOD.
Lumber, interior finish, packing-cases, and cooperage.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

22.
MODULUS OF ELASTICITY.

1,360,000.
MODULUS OF RUPTURE.

7,000.
REMARKS.

These trees form an important part of local mountain forests and furnish
much lumber locally. They grow best on rich bottom lands, but are
also found at altitudes of five thousand and even six thousand feet.
The balsam contained in blisters in the young bark is used in medicine.
The specific name grandis was given because of the great size to which
some trees of this species grow. See also " Lowland Fir," Pinchot
(United States Forest Service, Silvical Leaflet No. 5, 1907).

CONIFEROUS TRUNKS AND WOODS 75

Red Fir. Abies magnified Murr

NOMENCLATURE (Sudworth).

California Red Fir, California Magnificent Fir, Golden Fir (Cal.).
Red-bark Fir (Cal.).

LOCALITIES.

Mountains of northern California, Oregon, and Nevada.

FEATURES OF TREE.

One hundred to two hundred and fifty feet in height; six to ten feet in
diameter; large, erect cones; beautiful form.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish; sapwood distinguishable; rather close-grained; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.

Light and soft; not strong, durable when exposed, liable to injury in
seasoning.

REPRESENTATIVE USES OF WOOD.
Construction, sills, lumber, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

29.
MODULUS OF ELASTICITY.

940,000.
MODULUS OF RUPTURE.

9,900.
REMARKS.

The specific name refers to the appearance and size of the tree.

76 ORGANIC STRUCTURAL MATERIALS

White Fir, Balsam Fir. Abies concolor Lindl. and Gord.

NOMENCLATURE (Sudworth). White Balsam (Utah).

Silver Fir, Balsam (Cal.). Balsam-tree (Idaho).

California White Fir (Cal.). Colorado White Fir, Concolor White

Black Gum, Bastard Pine (Utah). Fir.

LOCALITIES.

Rocky Mountains and coast ranges; high elevations.

FEATURES OF TREE.

Seventy to one hundred and fifty feet in height; three to five feet in
diameter; the blisters in the bark are filled with clear pitch.1

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown to nearly white; sapwood same or darker; coarse-
grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong; without odor.

REPRESENTATIVE USES OF WOOD.

Butter-tubs, packing-boxes, and lumber.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

22.
MODULUS OF ELASTICITY.

1,290,000.
MODULUS OF RUPTURE.

9,900.
REMARKS.

Not always distinguished from the species Abies lowiana.

*" White Fir," Pinchot (United States Forest Service, Silvical Leaflet
No. 4, 1907).

CONIFEROUS TRUNKS AND WOODS 77

Red Fir, Noble Fir. Abies nobilis LindL

NOMENCLATURE (Sudworth).

Noble Silver Fir, Noble Red Fir. Bigtree, Feather-cone, Red Fir
Larch (Oreg.). (Cal.).

LOCALITIES.

Northwestern United States; cultivated in the East.

FEATURES OF TREE.

One to two hundred feet in height; six to nine feet in diameter; the
leaves are curved; a large, beautiful tree.1

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish-brown; sap wood darker; rather close-grained; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, hard, strong, and elastic.

REPRESENTATIVE USES OF WOOD.
Fitted for house-trimmings.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,800,000.
MODULUS OF RUPTURE.

22,200.
REMARKS.
Red Fir trees grow at elevations of three thousand and four thousand feet.

With other fir trees, they form extensive forests. The wood is often

sold as Larch.

1 Peters (Forestry and Irrigation, Vol. VIII, No. 9, Sept., 1902, pp. 362,
366); "Noble Fir," Pinchot (United States Forest Service, Silvical Leaflet
No. 7, 1907).

HEMLOCK

Tsuga

Hemlock trees grow in some of the central and northern states
east of the Rocky Mountains, and also on the Pacific Coast as
far north as Alaska. They sometimes mingle with other trees,
and sometimes form pure forests by themselves.

The wood of the Eastern Hemlock (Tsuga canadensis) is
coarse, brittle, often cross-grained, usually hard to work, liable
to warp and splinter, and perishable when exposed. It cannot
be relied upon to sustain shocks. It holds nails firmly and is
used for coarse lumber, dimension pieces, paper pulp, and cheap
finish. Some of the prejudice that exists against hemlock is due
to the fact that it was formerly compared with white pine, spruce
and fir. The supplies of these better woods have since diminished
and the value of hemlock has increased correspondingly.

The wood of the Western Hemlock (Tsuga heterophylla) , which
is much better and stronger than Eastern Hemlock, has suffered
because of the reputation of the Eastern Hemlock. Western
Hemlock has a pronounced odor which makes it disliked by
insects and rodents. For this reason it is sometimes used to
line grain-bins. The wood is also used for flooring, mill frames,
boxes, and paper pulp. It is seldom sold under its true name,
but names such as Alaska Pine and Red Fir are preferred. Black
streaks sometimes exist with the grain. These are more or less
evident and the pieces in which the streaks exist are often sold
as Black Hemlock. The True Black or Alpine Hemlock (Tsuga
mertensiana) often grows at high altitudes or in the far North and
is not yet widely available.1

Hemlock trees have flat, blunt, evergreen leaves, the under-
sides of which appear to be whitened. The leaves are arranged
in two ranks. The inner bark is red.

The Western Hemlock (Tsuga heterophylla} grows from Alaska to Cali-
fornia and attains a height of one hundred and eighty feet and a diameter
of nine feet. It is said to afford heavier and better wood than that obtained
from the common Hemlock. The Western Hemlock is known by the fol-
lowing names (Sudworth) : Western Hemlock, Hemlock Spruce (Cal.); Hem-

78

CONIFEROUS TRUNKS AND WOODS 79

lock (Oreg., Idaho, Wash.); Alaska Pine (Northwestern Lumberman);
Prince Albert's Fir, Western Hemlock Fir, California Hemlock Spruce
(England).2

l" Black Hemlock (Tsuga mertensiana) (United States Forest Service,
Silvical Leaflet No. 31, 1908).

2 "The Western Hemlock," Allen (United States Forestry Bureau,
Bulletin No. 33); "Mechanical Properties of Western Hemlock," Goss
(United States Forest Service, Bulletin No. 115).

80 ORGANIC STRUCTURAL MATERIALS

Hemlock. Tsuga canadensis (L.) Carr

NOMENCLATURE (Sudworth). Hemlock Spruce (Vt., R. I., N. Y.,

Hemlock (local and common Pa., N. J., W. Va., N. C., S.C.)

name).

Spruce (Pa., W. Va.).
Spruce Pine (Pa., Del., Va.,
N. C., Ga.).

LOCALITIES.

Eastern and central Canada, southward to North Carolina and Tennessee.

FEATURES OF TREE.

Sixty to eighty or more feet in height; two or three feet in diameter; short
leaves, green above and white beneath; straight trunk, beautiful
appearance.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish brown; sapwood distinguishable; coarse, pronounced,
usually crooked grain.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, not strong or durable, brittle, difficult to work; the wood
splinters easily; it retains nails firmly.

REPRESENTATIVE USES OF WOOD.

Coarse lumber, joists, rafters, laths, plank walks, and railway ties.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

26.
MODULUS OF ELASTICITY.

1,270,000.
MODULUS OF RUPTURE.

10,400.
REMARKS.

The specific name canadensis refers to Canada, the locality where these
trees excel. See also "The Eastern Hemlock," Frothingham (United
States Department of Agriculture, Bulletin No. 152, 1915). The
Southern or Carolina Hemlock (Tsuga caroliniana) yields wood
that resembles that of Hemlock.

LARCH OR TAMARACK

Larix

The Eastern Larch (Larix americand) grows in low, wet areas
known as tamarack swamps. The Western species (Larix
occidentalis) grows where it is dry and the European Larch (Larix
europcea) also thrives upon dry soil.

Many interesting records exist with regard to the wood, which
was apparently known and prized centuries ago. It was men-
tioned by Pliny, and Vitruvius wrote of a bridge, which having
burned, was replaced by one of Larch, because it was« thought
that that wood would not burn as readily. Some of the piles
upon which the city of Venice is founded are said to be of larch.1
While seemingly authoritative, such statements should be re-
ceived with caution, since the names of woods mentioned by
ancient writers are not always those employed at the present
time.

Larch wood is hard and very durable. In structure it resem-
bles spruce, and in weight and appearance it resembles hard pine.
The tall, straight trunks are so slender that they are seldom cut
up into lumber. The trunks are usually used for poles, posts,
and railway ties. Although the Eastern species is usually found
in deep swamps, it often grows better on drier ground. A
swamp specimen required forty-eight years to reach a diameter
of two inches, while another specimen, located where there was
less water, was eleven inches thick at the end of thirty-eight
years. The European Larch is often employed in American
landscape effects.

The foliage of the Larch is shed every autumn, and, for this
reason, Larch trees are not truly " evergreen." The tufts of
small needle-like leaves are of a fresh pea-green color when they
first appear in the spring, and the trees are then very beautiful.
The trees present a somewhat gloomy appearance in the winter.
Larch trees are very hardy, and the species deserves more atten-
tion than it receives.

81

82 ORGANIC STRUCTURAL MATERIALS

The European Larch (Larix europcea) is a native of central
Europe. The trees thrive upon dry soil and are used in
American landscape work. They are good coniferous trees to
plant near houses, because they lose their leaves during the
winter. The wood is similar to that obtained from American
species. The European Larch yields the Venice turpentine of
commerce. This substance, once collected through Venetian
markets, is now largely drawn from America. See also
" European Larch," Pinchot (United States Forest Service,
Circular No. 70).

1 Pliny, XVI, 43-49 and XVI, 30; also Vitruvius II, 9; also Encyclo-
paedia Britannica, Vol. XIV, p. 310; and "Forestry in Minnesota," Green.

CONIFEROUS TRUNKS AND WOODS 83

/ Larix americana Michx.

Tamarack, Larch. < T . 7 .. fr. D .,. ^ ,
\ Larix lancina (Du Roi) Koch

NOMENCLATURE (Sudworth). Black Larch, Red Larch (Minn.,

Tamarack, Larch, American Mich.).

Larch (local and common Juniper (Me., Canada).

names).
Hackmatack (Me., N. H., Mass.,

R. I., Del., 111., Mich.)

LOCALITIES.

From Newfoundland, Labrador, and Alaska, southward to New York,

Pennsylvania, and Minnesota
FEATURES OF TREE.

Seventy to ninety feet high; one to three feet in diameter; short, pea-green,
deciduous leaves in tufts ; a slender tree, winter aspect gloomy.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown; sapwood nearly white; coarse, conspicuous grain;
compact structure; annual layers pronounced.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, very strong, and durable; resembles spruce.

REPRESENTATIVE USES OF WOOD.

Railway ties, fence-posts, sills, ship-timbers, telegraph poles, flagstaffs, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

38.
MODULUS OF ELASTICITY.

1,790,000
MODULUS OF RUPTURE.

12,800.
REMARKS.

Almost all of the comparatively slender logs are used for poles, masts,
posts, and railway ties. Very few of them are cut up into lumber. Lumber-
men sometimes divide tamarack logs as they are "Red" or " White."
Red Tamarack is thought to be better and more durable than White Tama-
rack. This distinction is probably due to differences in the ages of the trees.
Tamarack trees grow in swamps, known as Tamarack Swamps, which are
often very extensive. See also "Transactions American Institute of Mining
Engineers" (Vol. XXIX, p. 157).

^ee also "Tamarack, Larix laricina (Du Roi)," Koch (United States
Forest Service, Silvical Leaflet No. 32, 1908).

84 ORGANIC STRUCTURAL MATERIALS

Tamarack, Larch. Larix occidentalis Nutt.

NOMENCLATURE (Sud worth). Western Larch, Great Western

Tamarack, Larch (local and Larch, Red American Larch.

common names). Western Tamarack (Cal.).
Hackmatack (Idaho, Wash.).

LOCALITIES.

Washington and Oregon, intermittently to Montana.

FEATURES OF TREE.

Ninety to one hundred and twenty-five feet high; two and one-half to
four feet in diameter; a large tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light red; thin sap wood lighter; coarse-grained; compact
structure; annual rings pronounced.

STRUCTURAL QUALITIES OF WOOD.
Hard, heavy, strong, and durable.

REPRESENTATIVE USES OF WOOD.

Posts, railway ties, and fuel; limited quantity of lumber; similar to Larch
(Larix americana).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

46.
MODULUS OF ELASTICITY.

2,300,000.
MODULUS OF RUPTURE.

17,400.
REMARKS.

These trees are much larger than those of the species Larix americana.
They also differ, in that they grow on dry ground, often at compara-
tively high elevations.1

1 See also "Mechanical Properties of Western Larch," Goss (United
States Forest Service, Bulletin No. 122); "Western Larch," Pinchot (United
States Forest Service Silvical Leaflet No. 14).

CEDAR

Cedrus, Thuya, Chamcscyparis, Libocedrus, Juniperus

The name Cedar was first applied to the true, foreign, or
Lebanon Cedars (Cedrus), but was later applied to certain
Arborvitaes (Thuya], Junipers (Juniperus), Cypresses (Chamce-
cyparis), and other trees1 that yield the durable, fine-grained
characteristically scented woods that are commonly known as
cedar woods. It is recorded that cedar was employed in such
early constructions as the Temple of Solomon and the Temple
of Diana at Ephesus,2 and it is possible that the product referred
to was the same as that to which this name applies at the present
time.

Cedar is divided as it is Red Cedar and White Cedar.

Red Cedar. — A large part of the supply is derived from the Eastern,
Western, and Southern species (Juniperus virginiana) , (Juniperus scopu-
lorum), and (Juniperus barbadensis) , The woods are soft, light, durable,
fine-grained, fragrant, and of a reddish-brown color. They are some-
times used in construction, but are more often employed in lead-pencils,
chests, and closets. The demand for wood to be used in lead-pencils
alone is very great.3 Cedar chips and shavings are often used in place
of camphor to protect woolens. The total demand is greater than the
supply. Trees grow easily on almost any soil. They are normally
hardy, but are sometimes subject to disease.4 Some of these diseases
cease after the trees have been felled and the wood cut from the diseased
trees is as durable as wood cut from trees that are not diseased.

The Western Red Cedar (Juniperus scopulorum) and the Southern
Red Cedar (Juniperus barbadensis) yield woods that resemble those
from the Cedar (Juniperus virginiana).

White Cedar. — Most " White Cedar" is obtained from several Arbor-
vitses and Cypresses. The woods are soft, light, durable, fine-grained,
and very inflammable. They are used for fence posts and shingles.
Practically all cedar that is not red cedar, is white cedar. White cedar
railway ties are defective because they crush and cut under the rails
and because they do not hold spikes. The trees often grow in swamps.5

85

86 ORGANIC STRUCTURAL MATERIALS

Some important Red and White Cedars are as follows:

Red Cedar White Cedar

Red Cedar (Juniperus virginiand) . Arborvitse (Thuya occidentalis) .
Red Cedar (Juniperus scopulorum). Canoe Cedar (Thuya gigantea).
Red Cedar (Juniperus barbadensis) . White Cedar (Chamcecyparis thy-

oides).
Port Orford Cedar (Chamcecyparis

lawsoniand) .
Yellow Cedar (Chamoecyparis nut-

katensis).

Incense Cedar (Libocedrus decur-
rens) .

1 See "Spanish Cedar" (Cedrela odorata}.

2 Pliny, 16, 213, and 16, 216.

3 "Notes on Red Cedar," Mohr (United States Division of Forestry,
Bulletin No. 31). See also "Uses of Commercial Woods of United States:
1, Cedars, Cypresses, and Sequoias" (United States Forest Service, Bulletin
No. 95, 1911).

4 Two diseases are recognized. They are white rot, caused by Polyporus
Juniperus, and red rot, caused by Polyporus carneus, von Schrenk (United
States Division Vegetable Physiology and Pathology, Bulletin No. 21);
also von Schrenk, Shaw School of Botany, Contribution No. 14 (St. Louis,
Mo.).

5 Timbered swamps are very formidable. For example, the " White Cedar
swamp," of the Lake Superior region, is covered close down to the ground, by
the vigorous branches of the trees. These branches meet and cross one
another, and passage through such a district resembles passage through a cul-
tivated hedge. The roots lie partly out of the water, and, while apparently
sound, are slippery and sometimes decayed, so that the pedestrian, stepping
or springing from one root to another, encumbered by burdens, and ob-
structed by the wiry branches, is liable to slip and fall. The constant use of
arms and legs, with the shock caused by packs shifting upon the shoulders
when the pedestrian falls, and the annoying insects, require much strength
and patience. Such Northern swamps can best be penetrated during the
winter season, when the ground is frozen. The "Tamarack swamp" of the
North differs from the " White Cedar swamp," in that the lower branches of
the Tamarack are higher from the ground. The "Cypress" is the charac-
teristic swamp tree of the South.

CONIFEROUS TRUNKS AND WOODS 87

Red Cedar. Juniperus virginiana Linn.

NOMENCLATURE (Sudworth). Savin (Mass., R. I., N. Y., Pa.,

Red Cedar (local and common Minn.).

name). Juniper, Red Juniper, Juniper Bush

Cedar (Conn., Pa., N. J., S. C., (local).

Ky., 111., la., Ohio).
Pencil Cedar, Cendre (La.).

LOCALITIES.

Atlantic Coast, Canada to Florida, westward intermittently to the Mississ-
ippi River in the North and the Colorado River in the South.

FEATURES OP TREE.

Fifty to eighty feet in height; two to three feet in diameter; dark-green,
scale-like foliage; loose, ragged, outer bark.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dull-red; thin sapwood nearly white; close, even grain; com-
pact structure; annual layers easily distinguishable.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, weak, and brittle; easily worked; durable; fragrant; the fra-
grance is such that the wood is used as an insecticide.

REPRESENTATIVE USES OF WOOD.

Ties, sills, posts, interior finish, pencil-cases, chests, and cigar-boxes.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

30.
MODULUS OF ELASTICITY.

950,000.
MODULUS OF RUPTURE.

10,500.
REMARKS.

The trunks of these trees are sometimes attacked by fungi similar to those
that attack Cypress and Incense Cedar trees. The disease stops when
the trees are felled, and boards cut from such trees have been known to
last for over fifty years. See also Contribution No. 44, Shaw School of
Botany, von Schrenk; "Two Diseases of Red Cedar" (United States
Division of Vegetable Physiology and Pathology, Bulletin No. 21);
Mohr (United States Forestry Bulletin No. 31); "Red Cedar," Pinchot
(United States Forest Service, Circular No. 73).

88 ORGANIC STRUCTURAL MATERIALS

Juniper. Juniperus occidentalis Hook

NOMENCLATURE (Sud worth). Cedar, Yellow Cedar, Western

Juniper (Oreg., Cal., Col., Utah, Cedar (Idaho, Col., Mont.).

Nev., Mont., Idaho, N. M.). Western Red Cedar, Western Juni-

per (local).

LOCALITIES.

California, Washington, Oregon, and Idaho.

FEATURES OF TREE.

Twenty-five to fifty feet in height; two to four feet in diameter; often
smaller.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish-brown; sapwood nearly white; very close-grained;
compact structure.

STRUCTURAL QUALITIES OF WOOD.
Ligfct, soft, and durable; receives a high polish.

REPRESENTATIVE USES OF WOOD.
Fencing, railway ties, posts, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

35.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

REMARKS.

Rarely found below an altitude of six thousand feet. Fruit said to be
eaten by Indians.

The California Juniper (Juniperus californica) grows intermittently in
some districts in California, near the coast line. The trees are sometimes
as much as thirty or forty feet in height, and one or two feet in diameter, but
are often much smaller. The shaggy bark is of a grayish color. The soft,
close-grained, fragrant, durable wood has been used to meet minor needs.

CONIFEROUS TRUNKS AND WOODS 89

White Cedar, Arborvitae. Thuya occidentalis Linn.

NOMENCLATURE (Sudworth). Atlantic Red Cedar (Cal.).

White Cedar, Arborvitse (local Vitse (Del.).

and common names).
Cedar (Me., Vt., N. Y.).

LOCALITIES.

Northern States, eastward from Manitoba and Michigan; northward, also
occasionally southward, as in the mountain region of North Carolina
and eastern Tennessee.

FEATURES OF TREE.

Thirty to sixty feet high; one to three or more feet in diameter; often
smaller; bruised leaves emit a characteristic pungent odor; the trunks
taper rapidly.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown, darkening with exposure; the thin sapwood is
nearly white; even, rather fine grain; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Soft, light, weak, brittle, durable, and inflammable; does not hold spikes
firmly.

REPRESENTATIVE USES OF WOOD.
Railway ties, telegraph poles, posts, fencing, shingles, and boats.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

19.
MODULUS OF ELASTICITY.

750,000.
MODULUS OF RUPTURE.

7,200.
REMARKS.

The comparatively slender trunks are seldom cut up into lumber, but are
used for poles; or else, the thin, upper ends are used for posts, and the
lower parts are flattened and used for ties. The wood is remarkably
durable. Hough describes a prostrate cedar tree over the trunk of
which a hemlock, which later exhibited one hundred and thirty yearly
bands, had taken root. The cedar tree had evidently been in contact
with the ground for at least one hundred and thirty years, yet much of
its wood was sound enough to be cut up into shingles.

90 , ORGANIC STRUCTURAL MATERIALS

Canoe Cedar, Arborvitae, Thuya plicata Don.
Giant Arborvitae. Thuya gigantea Nutt.

NOMENCLATURE (Sudworth). Cedar, Giant Cedar, Western Cedar

Canoe Cedar, Giant Arborvitse (Oreg., Cal.).

(local and common names). Shinglewood (Idaho).

Red Cedar, Giant Red Cedar,

Pacific Red Cedar (Wash.,

Oreg., Cal., Idaho).

LOCALITIES.

Coast region, California to Alaska, Idaho to Montana.

FEATURES OF TREE.

One hundred to two hundred feet in height; two to eleven feet in diameter;
the trunks are often buttressed at the surface of the ground; the tiny,
bright green leaves are scale-like.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dull reddish brown; the thin sapwood is nearly white; coarse-
grained; compact structure; annual layers distinct.

STRUCTURAL QUALITIES OF WOOD.

Soft, weak, light, brittle, easily worked, and very durable.

REPRESENTATIVE USES OF WOOD.

Shingles, fencing, cooperage, interior finish and canoes.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

23.
MODULUS OF ELASTICITY.

1,460,000.
MODULUS OF RUPTURE.

10,600.
REMARKS.

The large parts at the bottoms of the trees are usually hollow.

See also "Giant Arborvitae Thuya plicata Don," (United States Forest
Service Silvical Leaflet No. 11, 1907); " Western^Red Cedaiy^ Detwiler
(American Forestry, March, 1916).

CONIFEROUS TRUNKS AND WOODS 91

White Cedar. Chamcecyparis thyoides L.

NOMENCLATURE (Sudworth). Post Cedar, Swamp Cedar (Del.).

White Cedar (local and common Juniper (Ala., N. C., Va.).
name).

LOCALITIES.

Maine to Florida, Gulf Coast to Mississippi; best in Virginia and North
Carolina.

FEATURES OF TREE.

Sixty to eighty feet in height; three to four feet in diameter; shaggy,
rugged bark; a graceful tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood pinkish brown to darker brown; sap wood lighter; close-
grained; compact structure; conspicuous layers.

STRUCTURAL QUALITIES OF WOOD.

Very light and soft; not strong; extremely durable in exposed positions;
fragrant; easily worked; White Cedar posts last for many years.

REPRESENTATIVE USES OF WOOD.

Boats, railway ties, fencing, poles, posts, and shingles.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
23 (United States Forestry Division).1
20.

MODULUS OF ELASTICITY.

910,000 (average of 87 tests by United States Forestry Division).1
570,000.

MODULUS OF RUPTURE.

6,310 (average of 87 tests by United States Forestry Division).1
6,400.

REMARKS.

These trees often grow in swamps, as see footnote, page 86.

p. 33.

92 ORGANIC STRUCTURAL MATERIALS

Port Orford Cedar, Lawson Cypress. Chamcecyparis lawsoniana Murr.

NOMENCLATURE (Sudworth).

White Cedar, Oregon Cedar, Ginger Pine (Cal.).

(Oreg., Cal.).

LOCALITIES.

Pacific Coast, California and Oregon.

FEATURES OF TREE.

One hundred to sometimes two hundred feet in height; four to ten feet in
diameter; the leaves overlap in sprays; the very small cones are one-
fourth of an inch in diameter. 1

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood yellowish-white; sapwood similar; very close-grained.

STRUCTURAL QUALITIES OF WOOD.
Light and hard; strong, durable, and easily worked; fragrant; resinous.

REPRESENTATIVE USES OF WOOD.
Lumber, flooring, interior finish, ties, posts, matches, and shipbuilding.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,730,000.
MODULUS OF RUPTURE.

12,600.
REMARKS.
The resin is employed as an insecticide.

xSee also "Port Orford Cedar," Pinchot (United States Silvical Leaflet
No. 2).

The Yew (Taxus) yields a close-grained wood that suggests Cedar, save
that it is tough like Hickory. The early Celtic races associated Yew trees
with funerals. The wood was one of the "fighting woods" of the Greeks.
The best Yew bow-staves came from Italy, Turkey and Spain, and were dis-
tributed through the Venetian markets. Spanish staves were once so impor-
tant that they were controlled by the Spanish Government. More recently,
European bows were backed with other and more plentiful woods. Yew is
now occasionally employed for chairs, canes, and whips.

Pacific Coast Indians prized the Western, Oregon, or California Yew
(Taxus brevifolia) for bows, paddles, and fish hooks. The Florida Yew
(Taxus floridana) is another United States species. Ernest Thompson Seton
classes American woods suitable for bows in order of excellence as follows:
"Oregon Yew, Osage Orange, White Hickory, Elm, Cedar, Apple, etc."

CONIFEROUS TRUNKS AND WOODS^ 93

Yellow Cedar, Yellow Cypress, Sitka Cypress.

f Chamcecyparis nootkatensis (Lamb) Spach
\ Chamcecyparis nutkaensis Spach

NOMENCLATURE (Sudworth).

Nootka Cypress, Nootka Sound Alaska Cypress, Alaska Ground
Cypress (local). Cypress (local).

LOCALITIES.

Oregon to Alaska.

FEATURES OF TREE.

One hundred or more feet in height; three to five or more feet in diameter;
sharp-pointed, overlapping leaves; small, globular cones.

COLOR, APPEARANCE. OR GRAIN OF WOOD.

Heartwood clear light yellow; thin sapwood nearly white; close-grained;
compact structure.

STRUCTURAL QUALITIES OF WOOD.

Light, not strong, brittle, and hard; durable in contact with soil; easily
worked; receives a high polish; fragrant.

REPRESENTATIVE USES OF WOOD.

Ship-building, furniture, and interior finish.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

29.
MODULUS OF ELASTICITY.

1,460,000.
MODULUS OF RUPTURE.

11,000.
REMARKS.

A valuable lumber tree.

94 ORGANIC STRUCTURAL MATERIALS

Incense Cedar, White Cedar. ( Libocedrusdecurrens Torr.

( Heydena decurrens.
NOMENCLATURE (Sudworth).

Post Cedar, California Post Cedar California White Cedar (local),
(local). Juniper (Nevada).

Bastard Cedar, Red Cedar.

LOCALITIES.

California, Lower California, Oregon, and Nevada.

FEATURES OF TREE.

Ninety to one hundred and twenty-five feet in height, occasionally
higher; three to six feet in diameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish; sapwood lighter; close-grained; compact struc-
ture; heartwood often pitted; fragrant.

STRUCTURAL QUALITIES OF WOOD.
Light, brittle, soft, and durable.

REPRESENTATIVE USES OF WOOD.

t Flumes, shingles, and interior finish. ^e^c^ jM&tjf +"*- '

* v * "
WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

25.
MODULUS OF ELASTICITY.

1,200,000.
MODULUS OF RUPTURE.

960,000.
REMARKS.

The heartwood of these trees is often attacked by fungi that create large,
oval pits. The wood between the decayed spaces is apparently sound,
even in living trees. The disease stops when the trees are felled, and
the wood that remains is so durable that it can be used for posts
or for other purposes where appearance is not important. Some
dealers charge as much for wood with pits as for that without pits.
This disease is similar to the diseases that attack Cypress and Red
Cedar. It is said that about one-half of the standing supply of In-
cense Cedar has been affected by this disease, which is popularly known
as "pin rot" (see also von Schrenk, Contribution No. 14, Shaw School
of Botany).

CYPRESS

Cupressus and Taxodium

The name Cypress has been applied to trees of the genera
Chamcecyparis, Cupressus, and Taxodium. Most of the species
of the genus Chamcecyparis are now classed as Cedars. The
genus Cupressus includes true Cypresses, and is important in
Europe, but the trees themselves, rather than their woods, are
valued in the United States. The single species of the genus
Taxodium is not a Cypress, but the trees of this species supply
the " cypress wood" of American commerce. The name Cypress
will be applied only to the true Cypresses (Cupressus), and to
the commercial Cypress (Taxodium).

True cypress wood is mentioned by Herodotus and other an-
cient authors, and is construed by some to have been the " Gopher
wood" of which the Ark was built.1 Pliny mentions cypress
doors that were good after four hundred years, and a cypress
statue that was preserved for six hundred years. It is said that
the cypress gates of the early Saint Peter's, removed after one
thousand years of service, were found to be in excellent condi-
tion.2 Cypress wood has been prized for mummy cases, and
cypress trees are yet planted as funeral emblems over graves in
Turkey and in Italy.3 The common or evergreen Cypress is the
principal species in Europe. The eight or nine American species
(Cupressus) do not produce valuable woods, but the trees are
sometimes used for ornamentation, as in hedges.

The Monterey Cypress (Cupressus macrocarpa) is evidenced by a
group of trees that includes the only original specimens of this species
that survive in the United States. The famous " seventeen mile drive"
near Monterey, California, passes through the district in which these
trees are located. Their weird forms, with gnarled, wind-beaten
branches, are very unusual. The fact that transplanted specimens of
the Monterey Cypress grow so readily in many places on the Pacific
Coast is hard to reconcile with the further fact that so few of the original
trees remain at the present time.

95

96 ORGANIC STRUCTURAL MATERIALS

American Cypress wood is obtained from the Bald Cypress
(Taxodium distichum) which grows on submerged lands and in
deep swamps, making unusual logging methods necessary. The
trees are subject to a peculiar fungus disease that causes cavities
such as would be made by driving pegs into the wood and then
withdrawing them, and wood thus affected is known as "peggy
cypress." The disease ceases as soon as trees are felled, and
wood then cut from them is as durable as wood cut from per-
fectly healthy trees. About one-third of the standing supply is
affected. American Cypress wood has many names. Pieces
that float and pieces that sink in water have been classed as
White Cypress and Black Cypress respectively. All dark
pieces are now classed as Black Cypress, while the tinted woods
are sometimes sold under the names of Red Cypress and Yellow
Cypress.4

The Bald Cypress bears needle-like leaves, which are about
three-fourths of an inch in length, and separated from one
another. They are not arranged in tufts as in the case of the
larch, yet the foliage resembles that of the larch, in that it is
shed at the end of the season. The name Bald Cypress is due to
the appearance of the trees after the leaves have fallen. The
roots that appear above the surface of the surrounding soil or
water are known as " cypress knees."

1 Pliny, 16, 214 and 16, 215; Herodotus, 4, 16; Virgil, Georgics, 2, 443.
Funk & Wagnalls' Standard Dictionary, quoting Horace Smith, "Gayeties
and Gravities," Chapter VII, p. 57.

2 Encyclopaedia Britannica, B. 6, p. 745.

3 Brockhaus, Konversations-Lexikon, B. 4, p. 654.

4 See also von Schrenk, (Contribution No. 14, Shaw School of Botany);
"Uses of Commercial Woods of the United States," Hall and Maxwell
(United States Forest Service, Bulletin No. 95, 1911); "The Cypress and
Juniper Trees of the Rocky Mountain Region," Sudworth (United States
Department of Agriculture, Bulletin No. 207); "The Southern Cypress,"
Matoon (United States Department of Agriculture, Bulletin No. 272, 1915);
"The Bald Cypress," Detwiler (American Forestry, October, 1916).

CONIFEROUS TRUNKS AND WOODS 97

Cypress, Bald Cypress. Taxodium distichum Rich.
NOMENCLATURE (Sudworth).

White Cypress (N. C., S. C., Fla., Swamp Cypress (La.).

Miss.). Deciduous Cypress (Del., 111., Tex.).

Black Cypress (N. C., S. C., Ala., Southern Cypress (Ala.).

Tex.).
Red Cypress (Ga., Miss., La., Tex.).

LOCALITIES.

South Atlantic and Gulf States, Maryland, through Florida to Texas,
Mississippi Valley from southern Illinois to the Gulf. Forms forests
in swamps and barrens.1

FEATURES OF TREE.

Seventy to one hundred and fifty feet in height; four to ten feet in diame-
ter; the knees on the roots often become hollow with old age; the
leaves are flat and deciduous.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish; sapwood nearly white; close, straight grain; the
trunks are frequently pitted by disease.

STRUCTURAL QUALITIES OF WOOD.

Light and soft; not strong; durable; green wood is often very heavy.

REPRESENTATIVE USES OF WOOD.

Carpentry, construction, cooperage, and railway ties.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
29 (United States Forestry Division).1

28.

MODULUS OF ELASTICITY.

1,290,000 (average of 655 tests by United States Forestry Division).2
1,460,000.

MODULUS OF RUPTURE.

7,900 (average of 655 tests by United States Forestry Division).2
9,600.

REMARKS.

Cypress is of ten divided into "White Cypress" and "Black Cypress,"
the difference being probably due to differences in the ages and environ-
ment of the trees from which these two grades were cut. Cypress
trees are often attacked by fungi that create pits in the wood. The
disease stops when the trees are felled, and the wood that remains is very
durable. This disease is similar to others that attack Incense Cedar
trees and Red Cedar trees.

1 See "Transactions American Institute of Mining Engineers" (Vol.
XXIX, p. 157).

2 See p. 33.

7

REDWOOD

Sequoia

These trees grow in California. There are two species as
follows :

The Common Redwood (Sequoia sempervirens) grows near the
coast line where it is said to " follow the fogs." The trees are
large and very perfect. The soft, light, clean, reddish-brown
wood works easily and can be obtained in large-sized pieces.

Fio. 29. — Assembling parts of redwood stave pipe.

The wood resists fire more than many others and is extremely
durable in exposed places. It repels some forms of terrestrial
wood-borers, but has given way before the attacks of shipworms.
It is used for fence posts, railway ties, water-pipes, house-trim,
flumes, coffins, and shingles. Average pieces are often used in
cheaper forms of indoor finish, while unusual and attractive
pieces, in which grain is distorted, are classed as Curly Redwood
and preferred in a better grade of work.

CONIFEROUS TRUNKS AND WOODS 99

Some of the trees of this species are so large that they have been con-
fused with the exceptional or "giant" specimens of the Mammoth Red-
wood. The fire-resisting qualities of the wood were shown in the build-
ings that existed in San Francisco before the earthquake. Redwood
was largely employed in these buildings, yet comparatively few fires
took place until the conflagration caused by the earthquake. Durability
is shown by trunks that fell in the forests one hundred or more years
ago. Some of these trunks not only have not rotted, but contain good
wood that can be used in construction. Resistance to attacks by land
wood-borers is shown by the stave-pipes used in irrigation work in the
West. These pipes usually remain safe from attack as long as the wood
remains wet and in use. It should be noted, however, that they are
sometimes attacked by termites while dry.

FIG, 30. — Completed redwood stave pipe with gate.

The Mammoth Redwood (Sequoia washingtoniana) is found
inland where there is less moisture. Some of the trees are the
most massive, although not the tallest, trees known to man.
Individuals three hundred and twenty feet high and thirty-five
feet in diameter have been measured. It is estimated that some
specimens twenty-five feet in diameter were thirty-six hundred
years old, and it is thought probable that under favorable condi-
tions such trees could have survived for a total of five thousand
years. The almost non-inflammable bark is sometimes nearly
two feet in thickness. Even the oldest trees are sound through-
out. The wood is brittle, but otherwise resembles and is seldom

100 ORGANIC STRUCTURAL MATERIALS

distinguished commercially from the wood of the Common Red-
wood. Many of the smaller trees of this species are cut down
every year, but the largest trees are now protected or used for
exhibition purposes. Most of these exceptional trees have
names such as the " Pride of the Forest/' the ''Grizzly Giant,"
and the "U. S. Grant." These exceptional specimens, which do
not exceed several hundred in number, are grouped in the Mari-
posa, Calavaras, and other groves.

The genus is notable, first, because of the present value of the
wood, and second, because the quick-growing, healthy trees are
likely to resist commercial extinction. The name Sequoia is
that of an Indian Chief. Redwood trees may be known by their
size and locality, and also by their fine, dull, evergreen leaves.1

^ee also "The Big Trees of California" (United States Forestry Division
Bulletin No. 28); "The Bigtree," Sudworth (United States Forest Serv-
ice Silvical Leaflet No. 19); "Redwood" (United States Forest Service
Bulletin No. 38); "Mechanical Properties of Redwood," Heim (United
States Forest Service, Circular No. 193, 1912); "The Secret of the Big
Trees," Huntington (United States Department of Interior, Document);
"Uses of Commercial Woods of the United States," Hall and Maxwell
(United States Forest Service, Bulletin No. 95, 1911).

CONIFEROUS TRUNKS AND WOODS 101

Redwood. Sequoia sempervirens (Lamb.} Endl.
NOMENCLATURE (Sudworth).

Redwood (local and common Sequoia, California Redwood, Coast
name). Redwood (local).

LOCALITIES.

Central and North Pacific Coast region.

FEATURES OF TREE.

Two hundred to three hundred feet in height, sometimes higher; six to
eight and sometimes twenty feet in diameter; straight, symmetrical
trunk; low branches are rare.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heart wood red, changing to reddish brown when seasoned; thin
sapwood nearly white; coarse, normally straight grain; compact
structure; very thick bark.

STRUCTURAL QUALITIES OF WOOD.

Light and soft; not strong; very durable; easily worked, and receives a high
polish; not resinous, and does not burn easily.

REPRESENTATIVE USES OF WOOD.

Timber, shingles, flumes, fence-posts, coffins, railway ties, water-pipes,
and interior decoration; the bark is made into souvenirs.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
26 (Census figure, see p. 33).

MODULUS OF ELASTICITY.

790,000 (average of 8 Humboldt specimens).1
1,140,000 (average of 7 Humboldt -specimens).1
960,000 (Census figure, see p. 33).

MODULUS OF RUPTURE.

4,920 (average of 9 Humboldt specimens).1
7,138 (average of 7 Mendocino specimens).1
8,400 (Census figure, see p. 33).

REMARKS.

Redwood is the principal construction wood of California. Occasional
pieces with curled or distorted grain are valued for minor cabinet
work.

The Bigtree, Mammoth Tree, or Giant Redwood (Sequoia washingtoniana)
is the largest tree known to man. The wood, which resembles that of the
Common Redwood, is used locally. See also " Bigtree, Sequoia washing-
toniana (Winsl.) Sudw." (United States Forest Service, Silvical Leaflet
No. 19, 1908); etc., etc.

1 Soule, Transactions American Institute of Mining Engineers (California
Meeting, 1899).

CHAPTER VI

BANDED TRUNKS AND WOODS (CONTINUE. )
BROADLEAF SERIES. PART ONE

Dicotyledons

The trees of the Broadleaf Series grow in natural forests and
under cultivation in many parts of the world. The Oaks,
Elms, Maples, and other so-called hardwood trees are of this
group.

Broadleaf woods are comparatively heavy in weight and, in
most cases, the arrangement of the wood-elements is more com-
plicated than in the woods of the Coniferous series. Broadleaf
woods are difficult to work in proportion as they are complicated
in cellular structure. Tiemann has compared the cellular struc-
ture of broadleaf woods with the cellular structure of coniferous
woods as follows:1

"The wood of the angiosperms (broadleaf woods), on the other hand,
is much more complex, as the vertical cells are exceedingly variable
both in size and character. The vertical cells, consisting of wood-fibers,
vessels, tracheids, and others, in some species of the angiosperms, are
often of four, or five distinct kinds, and vary in size and shape from the
finest hair of a few millimeters in length, to the long vessels as large as
the lead in a lead-pencil. There are also short, thin-walled cells inter*
spersed. The Oak is one of the most complex woods in this respect?
while the Red Gum and the Tulip are comparatively simple.

In the Conifers, it is the tracheids which give the strength to the
wood, but in the angiosperms it is the long, narrow, hair-shaped cells
or wood-fibers which are the chief parts of the structure producing the
strength. The latter are usually grouped in bunches and form the
principal structural feature in the angiosperms. In the late wood of the
annual rings, their walls, compared to their diameters, become exceed-
ingly thick. These also have pits, but of a simpler kind, which are slit-
like and known as "simple pits."

Broadleaf woods are used in construction, although the greater
need as to quantity in this field is met by the woods of the other
series. Woods for cabinet purposes and implements are drawn

102

BROADLEAF TRUNKS AND WOODS 103

from the present group which, with a few exceptions, cannot be
depended upon for the large, straight pieces so often obtained
from coniferous trees.

The comparatively broad leaves of the trees of this series are
usually distinguished from the more or less needlelike, resinous
leaves of the conifers. Most, but not all, broadleaf trees are
deciduous, and many, but not all, of the woods are comparatively
hard. The names " deciduous" and " hardwood" are less satis-
factory than the name " Broadleaf," which should be preferred.

1 " Wood Preservation" (American Railway Engineering and Maintenance
of Way Association, Bulletin No. 120, p. 361).

OAK

Quercus

The Oaks grow in many parts of the northern hemisphere, and
at high altitudes just south of the equator. The historical
importance of the wood was founded upon the reputation of the
English Oaks (Quercus robur var. pedunculata and Quercus robur
var. sessili flora) ,l which once formed large forests over parts of
northern and central Europe.

The woods were formerly relied upon to meet many needs in
ships and houses, and did not give way to iron for vessels, and to
the so-called softwoods for houses, until comparatively recent
periods. Practically all ships were built of wood until the battle
of the Merrimac and the Monitor; and oaken timbers were used
in many English houses, even of the cottage type, until the sup-
plies of softwoods from the Baltic forests and from those of North
America became easily available. Oak is yet used for railway
ties and high-grade construction timbers, but to a more limited
extent than formerly; while the demands for oak to be used in
cabinet work are constantly increasing.

Oak wood is tough and durable in contact with the ground. It
receives a high polish and is more or less easily obtained. On the
other hand, it is liable to warp and check in seasoning, and hard
to nail without splitting. It contains gallic acid, which attacks
iron fastenings. Experiments indicate that the iron is eventually
protected by the formation of a scale, and that the wood, although
darkened, remains practically uninjured. Oak bark is so
charged with gallic acid that it is used in the tanning of leather.

An experiment made to determine the effect of gallic acid upon iron2
was as follows: Five grams of clean iron wire were immersed in a 5
per cent, solution of gallic acid. In nine days the weight was 4.720
grams and the solution intensely black. Thirteen days later the same
specimen weighed 4.7453 grams. The fact that the iron increased in
weight during the last thirteen days, was thought to indicate the forma-
tion of a crust, which probably protected it to some extent.

104

BROADLEAF TRUNKS AND WOODS 105

Oak trees commonly require many years to reach maturity
but are then usually long lived. The leaves of some species are
deciduous, while those of others are evergreen. Oak trees bear
oblong thin-shelled kernels which protrude from hard scaly cups
and are known as acorns. In the United States the woods are
grouped under three heads as follows:

The White Oaks. — These woods, which are more or less easily obtained,
are preferred for most purposes. The principal sources are White Oak
(Quercus alba], Cow Oak (Quercus michauxii), Chestnut Oak (Quercus
prinus), Post Oak (Quercus minor}, Bur Oak (Quercus macrocarpa),
Pacific Post Oak (Quercus garryana).

The Red or Black Oaks. — These woods are inferior to the others, but
are yet very valuable. The principal sources are Red Oak (Quercus
rubra), Pin Oak (Quercus palustris), Spanish Oak (Quercus digitata),
Yellow or Black Oak (Quercus velutina) .

The Live Oaks. — The Live Oaks, which are among the hardest and
most durable of all construction woods, were formerly valued for ship
building. The supply is now limited. The name is due to the " live"
or evergreen leaves. The principal sources are Live Oak (Quercus vir-
giniana}, California Live Oak (Quercus agrifolia), Live Oak (Quercus
chrysolepis) .

1 Usually taken as sub-species or varieties of the species Quercus robur,
but thought by some botanists to be distinct species, namely, Quercus
pedunculata and Quercus sessiliflora.

2 Havemeyer Chemical Laboratory of New York University.

106 ORGANIC STRUCTURAL MATERIALS

White Oak. Quercus alba Linn.

NOMENCLATURE.

White Oak (general). Stave Oak (Ark.).

LOCALITIES.

Widespread throughout north-central and eastern United States.

FEATURES OP TREE.

Seventy-five to one hundred and fifty feet in height; three to six feet in
diameter; fine shape and appearance; grayish-white bark; compara-
tively sweet, ovoid, oblong acorns in rough, shallow cups; the leaves are
blunt, they are not bristle-tipped.

COLOR, GRAIN, OR APPEARANCE OF WOOD.

Heartwood brown with sapwood lighter; annual layers are well marked;
medullary rays are broad and prominent.

STRUCTURAL QUALITIES OF WOOD.

Tough, strong, heavy and hard; liable to check unless seasoned with care;
durable in contact with the soil; receives a high polish.

REPRESENTATIVE USES OF WOOD.

Ship-building, construction, cooperage, cabinet-making, railway ties,
fuel, etc. The bark is rich in tannin.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
50 (United States Forestry Division).1
46.

MODULUS OF ELASTICITY.

2,090,000 (average of 218 tests by United States Forestry Division).1
1,380,000.

MODULUS OF RUPTURE.

13,100 (average of 218 tests by United States Forestry Division).1
12,800.

REMARKS.

The best known of the American oaks. A tree of the first economic
importance. The cellular arrangement of the wood is complicated,
and, for this reason, the wood is hard to season. It stands well, how-
ever, after it has once been seasoned.2

1 See p. 33.

2 See also "White Oak," Pinchot (United States Forest Service, Circular
No. 106, 1907); "The American White Oak," Detwiler (American Forestry,
January, 1916); etc.

BROADLEAF TRUNKS AND WOODS 107

Cow Oak. Quercus michauxii Nutt.

NOMENCLATURE (Sud worth).

Cow Oak (local and common name). Swamp White Oak (Del., Ala.).
Basket Oak (Ala., Miss., La., Tex., Swamp Chestnut Oak (Fla.).
Ark.).

LOCALITIES.

Southeastern United States, Delaware, and Florida, westward along the
Gulf to Texas; also southern Indiana and Illinois to the Gulf; best on
rich bottoms in Arkansas and Louisiana.

FEATURES OF TREE.

Seventy-five to one hundred feet in height; three to six feet in diameter;
rough, light-gray bark with loose, scaly ridges; the leaves are only
shallowly toothed; the blunt teeth are not bristle-tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown; sapwood light-buff; conspicuous medullary rays;
close-grained.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, very strong, tough, durable, and easily split.

REPRESENTATIVE USES OF WOOD.

Construction, agricultural implements, and wheel-stock.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
46 (United States Forestry Division).1
50.

MODULUS OF ELASTICITY.

1,610,000 (average of 256 tests by United States Forestry Division.)1
1,370,000.

MODULUS OF RUPTURE.

11,500 (average of 256 tests by United States Forestry Division).1
15,800.

REMARKS.

The principal white oak of the Southern States; the acorns are devoured
by cattle, whence its name.

1 See p. 33.

108 ORGANIC STRUCTURAL MATERIALS

Chestnut Oak. Quercus prinus Linn.

NOMENCLATURE (Sudworth).
Chestnut Oak (local and com- Tanbark Oak (N. C.).

mon name). Swamp Chestnut Oak (N. C.).

Rock Oak (N. Y., Del., Pa.). Mountain Oak (Ala.).

Rock Chestnut Oak (Mass.,

R. I., Pa., Del., Ala.).

LOCALITIES.

Maine to Georgia, westward intermittently to Kentucky, Tennessee, and
Alabama; best development in southern Alleghany Mountain region.

FEATURES OF TREE.

Seventy-five to eighty feet in height; three to four feet in diameter; the
leaves resemble those of the Chestnut (Castanea dentata) ; the shallow
teeth are not bristle-tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark-brown; sapwood lighter; close-grained; conspicuous
medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Heavy, tough, hard, strong, and durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.
Largely used for railway ties, The bark is rich in tannin.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

46.
MODULUS OF ELASTICITY.

1,780,000.
MODULUS OF RUPTURE.

14,600.

REMARKS.1

1 See also "Chestnut Oak, Quercus prinus Linn." (United States Forest
Service, |Silvical Leaflet, No. 41, 1908).

BROADLEAF TRUNKS AND WOODS 109

{Quercus minor Sargent
Quercus obtusiloba Michx.
Quercus stellata Wang

NOMENCLATURE (Sudworth).

Post Oak (local and common Overcup Oak (Fla.).

name). White Oak (Ky., Ind.).

Iron Oak (Del., Miss., Neb.). Box Oak (Md.)

Box White Oak (R. I.). Brash Oak (Md.).
Chene Stone" (Quebec).

LOCALITIES.

East of Rocky Mountains — Nebraska and the Gulf States, eastward
intermittently to Massachusetts and northern Florida.

FEATURES OF TREE.

Fifty to seventy feet in height; two to three feet in diameter; a low shrub
in Florida; there are blunt lobes or projections to the leaves; the deeply-
cut lobes are not bristle-tipped; the leaves are clustered at the ends of
the branches; a fine tree with a rounded top.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light or dark brown with lighter sapwood; close-grained;
annual rings well marked; numerous and conspicuous medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; checks badly in drying; durable in contact with
the soil.

REPRESENTATIVE USES OF WOOD.

Largely used, particularly in the Southwest, for fencing, railway ties, and
fuel; also for cooperage, construction, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
50 (United States Forestry Division).1
52.

MODULUS OF ELASTICITY.

2,030,000 (average of 49 tests by United States Forestry Division).1
1,180,000.

MODULUS OF RUPTURE.

12,300 (average of 49 tests by United States Forestry Division).1
12,900.

REMARKS.

A common tree in the Gulf States west of the Mississippi River. The
wood of this species is seldom distinguished commercially from that of
white oak.

1 See p. 33.

110 ORGANIC STRUCTURAL MATERIALS

Bur Oak. Quercus macrocarpa Michx.

NOMENCLATURE (Sudworth).

Bur Oak (local and common Mossycup Oak (Mass., Pa., Del.,

name). Miss., La., Tex., Ark., 111., Iowa,

Overcup Oak (R. I., Del., Pa., Neb., Kan.).

Miss., La., 111., Minn.). Scrub Oak (Neb., Minn.).

Mossycup White Oak (Minn.). Overcup White Oak (Vt.).

LOCALITIES.

Nova Scotia to Manitoba, Wyoming, Georgia, and Texas.

FEATURES OF TREE.

Seventy to one hundred and thirty feet in height; five to seven feet in
diameter; deep, opposite depressions in leaves; the deeply-cleft lobes
are not bristle-tipped; this is the only Oak yielding structural woods
which bears acorns with mossy, fringed borders around their cups;
there are corky ridges on the twigs and young branches.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood rich brown; sapwood lighter; close-grained; broad, conspicu-
ous medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, strong, tough, and very durable in contact with the ground.

REPRESENTATIVE USES OF WOOD.

Similar to those of the White Oak (Quercus alba).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

46.
MODULUS OF ELASTICITY.

1,320,000.
MODULUS OF RUPTURE.

13,900.
REMARKS.

The range extends farther into the West and Northwest than that of
other Eastern oaks. The Bur Oak has been recommended for planting
on the prairies.1

xSee also "Bur Oak," Pinchot (United States Forest Service, Circular
No. 56, 1907).

BROADLEAF TRUNKS AND WOODS 111

White Oak. Quercus garryana Douglas

NOMENCLATURE (Sudworth).

White Oak (Cal., Oreg.)- Oregon White Oak (Cal.).

Pacific Post Oak (Oreg.). California Post Oak.

Western White Oak (Oreg.).

LOCALITIES.

Pacific Coast, British Columbia into California.

FEATURES OF TREE.

Sixty to ninety feet high; one and one-half to two and one-half feet in
diameter; a small shrub at high elevations; the rounded lobes of the
leaves are not bristle-tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown or yellow; sapwood lighter, often nearly white;
compact structure; distinctly-marked annual rings; medullary rays
often conspicuous.

STRUCTURAL QUALITIES OF WOOD.
Heavy, strong, hard, and tough.

REPRESENTATIVE USES OF WOOD.

Ship-building, carriages, furniture, indoor decoration, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

46.
MODULUS OF ELASTICITY.

1,150,000.
MODULUS OF RUPTURE.

12,400.
REMARKS.

Locally, this tree is important. The best substitute for Eastern White
Oak produced on the Pacific Coast.1

The Weeping, Valley, Swamp, White, or California White Oak (Quercus
lobata), a native of central-western California, is one of the largest and most
symmetrical of all oaks. It adds to landscapes where it grows as the elms
add to landscapes in the East. The brittle wood is seldom used in construc-
tion, but is an important local fuel.

^ee also "Oregon Oak," Graves (United States Forest Service, Silvical
Leaflet No. 52, 1912).

112 ORGANIC STRUCTURAL MATERIALS

Red Oak. Quercus rubra Linn.

NOMENCLATURE (Sudworth).

Red Oak (local and common name). Spanish Oak (Pa., N. C.).
Black Oak (Vt., Conn., N. Y., Wis.,
la., Neb., So. Dak., Ont.).

LOCALITIES.

East of the Rocky Mountains, Nova Scotia to Florida, westward
intermittently to Nebraska and Kansas; best in Massachusetts.

FEATURES OF TREE.

Ninety to one hundred feet in height; three to six feet and over in diameter;
the brownish-gray bark is smooth on the branches; the leaves have
sharp-pointed, bristle-tipped lobes; there are relatively small acorns
in flat, shallow cups; a fine, complete tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown or red; sapwood lighter; coarse-grained; well-
marked annual rings; medullary rays few, but broad,

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; inclined to check in drying; acid; red oak is
inferior to white oak.

REPRESENTATIVE USES OF WOOD.

Works of secondary importance, clapboards, cooperage, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
45 (United States Forestry Division).1
40.

MODULUS OF ELASTICITY.

1,970,000 (average of 57 tests by United States Forestry Division).1
1,600,000.

MODULUS OF RUPTURE.

11,400 (average of 57 tests by United States Forestry Division).1
14,000.

REMARKS.

The Red Oak grows more rapidly than other oaks. The bark is used in
tanning.

1 See p. 33.

BROADLEAF TRUNKS AND WOODS 113

Pin Oak. Quercus palustris

NOMNECLATURE (Sudworth). Water Oak (R. I., 111.).

Pin Oak (local and common Swamp Oak (Pa., Ohio, Kans.),

name).
Swamp Spanish Oak (Ark., Water Spanish Oak (Ark.).

Kan.).

LOCALITIES.

Massachusetts, Michigan, and Missouri, southward to Virginia, Ten-
nessee, and Oklahoma.

FEATURES OF TREE.

Fifty to eighty feet in height; two to four feet in diameter; a full-rounded
or pyramidal top; the bark is thin and smooth ; there are numerous small,
pin-like branches; the leaves are deeply-cleft; their lobes are bristle-
tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood variegated light-brown; sap wood nearly white; coarse-grained;
medullary rays numerous and conspicuous.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; checks badly in seasoning.

REPRESENTATIVE USES OF WOOD.

Shingles, clapboards, construction, interior finish, and cooperage.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

43.
MODULUS OF ELASTICITY.

1,500,000.
MODULUS OF RUPTURE.

15,400.
REMARKS.

The numerous slender, secondary branches suggest pins and cause the tree
to be easily recognized, even in winter.

114 ORGANIC STRUCTURAL MATERIALS

( Quercus digitata Sudworth

Spanish Oak. \ Quercus falcata Michx.

( Quercus triloba

NOMENCLATURE (Sudworth).

Spanish Oak (local and common name).

Red Oak (N. C., Va., Ga., Fla., Ala., Miss., La., Ind.).

LOCALITIES.

New Jersey and Florida, westward intermittently to Illinois and Texas;
most abundant in the Gulf States.

FEATURES OF TREE.

Thirty to seventy feet in height; two and one-half to four feet in diameter;
variable foliage; the deeply-cleft, sharp-pointed leaves are bristle-
tipped; the acorns are globular to oblong.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-red; sap wood lighter; coarse-grained; the annual layers
are strongly marked; the medullary rays are few, but conspicuous.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, and strong; not durable; checks badly in drying.

REPRESENTATIVE USES OF WOOD.

Somewhat used for cooperage, construction, etc. The bark is very rich in
tannin.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

43.
MODULUS OF ELASTICITY.

1,900,000.
MODULUS OF RUPTURE.

16,900.
REMARKS.

Grows rapidly, often on dry, barren soil.

BROADLEAF TRUNKS AND WOODS 115

I Quercus velutina Lam.
Black Oak, Yellow Oak. |

NOMENCLATURE (Sudworth).

Black Oak, Yellow Oak (local Tanbark Oak (111.).

and common names). Spotted Oak (Mo.).

Yellow Bark, Yellow-bark Oak Quercitron Oak (Del., S. C., La.,

(R.I., Minn.). Kans., Minn.).
Dyer's Oak (Tex.).

LOCALITIES.

East of longitude 96 degrees; Maine and Florida, westward intermittently
to Minnesota and Texas; best in North- Atlantic States.

FEATURES OF TREE.

Ninety to one hundred and thirty feet in height; three to five feet in diam-
eter; dark-gray to black bark; yellow inner bark; the acorns have bitter,
yellow kernels; the foliage turns handsomely in the autumn; the sharply-
cleft leaves are bristle-tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light reddish-brown; sapwood lighter; coarse-grained; the
annual layers are strongly marked; the medullary rays are thin.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; liable to check in drying; not tough.

REPRESENTATIVE USES OF WOOD.

Cooperage, construction, furniture, and decoration.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
45 (United States Forestry Division).1
44.

MODULUS OF ELASTICITY.

1,740, 000 (average of 40 tests by United States Forestry Division).1
1,470,000.

MODULUS OF RUPTURE.

10,800 (average of 40 tests by United States Forestry Division).1
14,800.

REMARKS.

The yellow inner bark affords a yellow dye

See p. 33.

116 ORGANIC STRUCTURAL MATERIALS

Liv Oak ^ Quercus virginiana Mill.

\ Quercus virens Ait.

NOMENCLATURE (Sudworth).

Live Oak (Va., N. C., S. C., Ga., Chene Vert (La.).
Fla., Miss., Ala., Tex., La.,
Gal.).

LOCALITIES.

Atlantic Coast from Virginia to Florida, westward to Texas and Lower
California; southern Mexico, Central America, and Cuba; a Southern
species; grows best in South- Atlantic States.

FEATURES OF TREE.

Fifty to sixty feet in height; three to six feet in diameter; general resem-
blance to the Apple-tree; evergreen foliage; the oblong, blunt leaves are
not bristle-tipped.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown or yellow; sap wood nearly white; close-grained;
compact structure; the medullary rays are pronounced; the annual
layers are often hardly distinguishable.

STRUCTURAL QUALITIES OF WOOD.

Heavy, strong, tough, and hard; difficult to work; splits easily; receives
a high polish; very durable.

REPRESENTATIVE USES OF WOOD.
Ship-building.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

59.
MODULUS OF ELASTICITY.

1,600,000.
MODULUS OF RUPTURE.

14,000.
REMARKS.

The trunks and branches furnish small, straight pieces, but the principal
yield is in knees and crooked or compass timbers. The wood splits so
easily that it is often fastened with bolts or trenails, rather than with
spikes. The trees, which are now scarce, grow rapidly.

BROADLEAF TRUNKS AND WOODS 117

California Live Oak. Quercus agrifolia Nee

NOMENCLATURE (Sudworth).

Coast Live Oak (Cal.). Encena (Gal.).

California Live Oak (Cal.). Evergreen Oak (Cal.).

LOCALITIES.

California and Lower California.

FEATURES OF TREE.

Forty to seventy-five and occasionally more feet in height; three to six
feet in diameter; evergreen foliage; the leaves are spiked like those of
the Holly; the shape resembles that of the Apple-tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood creamy-white, darkens on exposure; compact structure; the
annual layers are hardly distinguishable.

STRUCTURAL QUALITIES OF WOOD.
Heavy and hard, but brittle.

REPRESENTATIVE USES OF WOOD.
Fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

61.

MODULUS OF ELASTICITY.

1,350,000.
MODULUS OF RUPTURE.

13,200.
REMARKS.

118 ORGANIC STRUCTURAL MATERIALS

Live Oak. Quercus chrysolepis Liebm.

NOMENCLATURE (Sudworth).

Live Oak (Cal., Oreg.). Canyon Oak, Iron Oak, Maul Oak,

Canyon Live Oak, Black Live Valparaiso Oak (Cal.).
Oak, Golden-cup Oak (Cal.).

LOCALITIES.

West of the Rocky Mountains, in canyons and at high elevations.

FEATURES OF TREE.

Fifty to eighty feet in height; three to six feet in diameter; often a low
shrub; impressive appearance; evergreen foliage; some leaves have
smooth, thickened margins, but occasionally leaves have spiny-toothed
margins.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown; sap wood lighter; there are small pores in the
wide bands that are parallel to the conspicuous medullary rays; close-
grained.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, strong, tough, and difficult to work.

REPRESENTATIVE USES OF WOOD.

Implements, wagons, and tool-handles.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

52.
MODULUS OF ELASTICITY.

1,700,000.
MODULUS OF RUPTURE.

18,000.
REMARKS.

Said to be the most valuable of the California oaks. Grows at eleva-
tions of two thousand to five thousand feet. The Highland Live Oak
(Quercus wislizeni) is an evergreen tree which also grows on the Pacific
Coast. The Highland Live Oak differs from the Live Oak (Quercus
chrysolepis) in the fact that the leaves of the former are always spiny-
toothed.

BROADLEAF TRUNKS AND WOODS 119

English Oak. Quercus robur var. pedunculata

NOMENCLATURE.

English Oak. Common Oak.

British Oak.

LOCALITIES.

Widespread throughout northern and central Europe.

FEATURES OF TREE.

Seventy to one hundred feet in height; three to five feet in diameter;
the branches are crooked, the leaves stalkless, and the acorns long-stalked.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown, darker spots frequent; sap wood lighter; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.

Hard, tough, strong, and durable; difficult to work; liable to warp in
seasoning.

REPRESENTATIVE USES OF WOOD.

Ship-building, beams, and cabinet-work; used formerly in carpentry.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
51 (Laslett).

MODULUS OF ELASTICITY.
1,170,000 (Thurston).

MODULUS OF RUPTURE.
10,000 (Thurston).

REMARKS.

The English, Chestnut, Durmast, or Red Oak (Quercus robur var. ses-
siliflora), which is distinguished from the English Oak (Quercus robur
var. pedunculata)1 by its long leafstalks and its short acorn stalks,
yields a similar but lower-rated wood. These two trees supply the
"British Oak" of commerce. Dantzic, Rigi, and some other European
oaks are in all probability really English Oaks, which are named from
the ports from which they are shipped. Durmast Oak (Quercus pubes-
cens or Quercus robur intermedia) is not as common as the English Oak
(Quercus robur var. pedunculata) with which it is often confused.
Laslett states that it is often hard to distinguish one of these woods
from another without tracing the logs back to their original sources.
Early authorities advised that these woods, which contain much gallic
acid, should not be fastened with iron; but the woods are now better
seasoned, and, as stated before, oak woods are now safely fastened with
iron, at least in the United States.

1 As stated, these two trees are usually assumed to be sub-species or varie-
ties of the species Quercus robur. But by some they are believed to be dis-
tinct species, that is, Quercus pedunculata and Quercus sessiliflora.

ASH

Fraxinus

These trees grow in many places in the temperate regions of
the northern hemisphere.

The wood resembles oak in many particulars, but is coarser,
lighter, easier to work, tougher, more elastic, and less attractive
than oak. Ash seasons well, but does not last well when exposed
to the weather. It is used for stairs, furniture, and some of the
cheaper forms of cabinet work. Second-growth ash is tougher
and more pliable than first-growth ash.1

Ash woods are often grouped under two heads: White Ash
includes the lighter colored and more desirable pieces, while
Black Ash includes- the darker and inferior woods. This prac-
tical division agrees with the botanical division in the North,
since in the North the only notable species are White Ash
(Fraxinus americana) and Black Ash (Fraxinus nigra). The
wood of the Green Ash (Fraxinus lanceolata) of the south is
usually classed as White Ash. One-half of the thirty-nine known
species of the genus Fraxinus are natives of North America.2

1 Trees that grow up after virgin forests are cut away afford what are
known as " second-growth woods." Ordinarily, second-growth woods are
inferior to first-growth woods, because second-growth woods, being younger,
have more sapwood. In this case it is the sapwood that is often preferred.

2 See also "The Ashes: Their Characteristics and Management," Sterrett
(United States Department of Agriculture, Bulletin No. 299).

120

BROADLEAF TRUNKS AND WOODS 121

White Ash. Fraxinus americana Linn.

NOMENCLATURE (Sudworth).

White Ash (local and common Cane Ash (Ala., Miss., La.).

name). American Ash (la.).

Ash (Ark., la., Wis., 111., Mo.,
Minn.).

LOCALITIES.

Nova Scotia to Florida, westward intermittently to Minnesota and Texas;
greatest development in the Ohio River basin.

FEATURES OF TREE.

Forty-five to ninety feet in height, occasionally higher; three to four feet
in diameter; the dark-brown or gray-tinged bark is deeply divided by
narrow fissures into broad, flattened ridges; the seeds have long wings.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood reddish-brown, usually mottled; sapwood much lighter, some-
times nearly white; coarse-grained; compact structure; the layers are
clearly marked by large, open ducts; the medullary rays are often
obscure.

STRUCTURAL QUALITIES OP WOOD.

Heavy, hard, strong, and elastic, becoming brittle with age; not durable in
contact with the soil.

REPRESENTATIVE USES OF WOOD.

Agricultural implements, carriages, handles, oars, interior and cheap
cabinet-work.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
39 (United States Forestry Division).1
40.

MODULUS OF ELASTICITY.

1,640,000 (average of 87 tests by United States Forestry Division).1
1,440,000.

MODULUS OP RUPTURE.

10,800 (average of 87 tests by United States Forestry Division).1
12,200.

REMARKS.

These valuable trees grow rapidly, particularly when on low, rather moist
soil. They are not apt to form forests, but are usually found in clumps
or mingled with trees of other species. Large trees sometimes have
large heart-cracks. The trees are also subject to a fungus disease which
reduces the wood to a useless, soft, pulpy, yellowish mass. This dis-
ease, which is known as white rot, progresses until the tree becomes so
weak that it is blown over by the winds. The disease does not attack
dead or seasoned woods. See also von Schrenk (United States Bureau
of Plant Industry, Bulletin No. 32.)

lSee p. 33.

122 ORGANIC STRUCTURAL MATERIALS

-;

Red Ash < ^nmrms pennsylvanica Marsh

\ Fraxinus pubescens Lam.

NOMENCLATURE (Sudworth).

Red Ash (local and common Brown Ash (Mo.).

name). Black Ash (N. J.).

River Ash (R. I., Ont.). Ash (Neb.).

LOCALITIES.

New Brunswick to Florida, westward intermittently to the Dakotas and
Alabama; best developed in the North- Atlantic States.

FEATURES OF TREE.

Rarely much over forty-five feet in height and about one foot in diameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood rich brown; sapwood light brown, streaked with yellow;
coarse-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Heavy and hard; strong, but brittle.

REPRESENTATIVE USES OF WOOD.

Agricultural implements, handles, boats, oars, and paper-pulp.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

38.
MODULUS OF ELASTICITY.

1,154,000.
MODULUS OF RUPTURE.

12,300.
REMARKS.

Grows on borders of streams and swamps, in low, rich soil.

BROADLEAF TRUNKS AND WOODS 123

Blue Ash. Fraxinus quadrangulata Michx.

NOMENCLATURE (Sudworth).

Blue Ash (Mich., 111., Ky., Mo., Ala.).

LOCALITIES.

Ontario and Minnesota, southward to Tennessee, Alabama, and Arkansas.

FEATURES OF TREE.

Fifty to seventy-five feet in height, occasionally higher; one to two feet
in diameter; a slender tree; blue properties in inner bark; smooth,
square twigs; leaves composed of seven to eleven pointed, rough-
margined leaflets.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light yellow, streaked with brown; sapwood lighter; close-
grained; compact structure; satin-like appearance.

STRUCTURAL QUALITIES OF WOOD.

Hard and heavy, but brittle; not strong; the most durable of the Ash
woods.

REPRESENTATIVE USES OF WOOD.

Largely used in flooring, carriage-building, pitchfork and other tool-
handles.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

44.
MODULUS OF ELASTICITY.

1,100,000.
MODULUS OF RUPTURE.

11,500.
REMARKS.

Blue Ash trees grow best on limestone formations. The inner bark con-
tains properties which give water a bluish tint. Blue Ash has no supe-
rior among the Ash woods. Blue Ash pitchfork-handles are highly
prized.

124 ORGANIC STRUCTURAL MATERIALS

\ Fraxinus niqra Marsh
Black Ash. v« • » •* i- r

( Fraxinus samoucifoha Lam.

NOMENCLATURE (Sudworth).

Black Ash (local and common Swamp Ash (Vt., R. I., N. Y.).

name). Brown Ash (N. H., Tenn.).

Water Ash (W. Va., Tenn., Ind.). Hoop Ash (Vt., N. Y., Del., Ohio,

111., Ind.).
LOCALITIES.

Newfoundland, through Canada to Manitoba, southward to Illinois,
Missouri, and Arkansas.

FEATURES OF TREE.

Seventy to eighty feet in height; one to one and one-half feet in diameter;
a thin tree; excrescences or knobs are frequent on trunks; dark, almost
black, winter buds.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood dark brown; sapwood light brown, often nearly white; coarse-
grained; compact structure; the medullary rays are numerous and thin.

STRUCTURAL QUALITIES OP WOOD.

Separates easily in layers; rather soft and heavy, tough, and elastic; not
strong or durable when exposed.

REPRESENTATIVE USES OP WOOD.

Largely used for interior finish, fencing, barrel-hoops, cabinet-making,
splint baskets, an4 chair-bottoms.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

39.
MODULUS OF ELASTICITY.

1,230,000.
MODULUS OF RUPTURE.

11,400.
REMARKS.

The Black Ash is found farther north than other Ash trees. It is one of
the most slender of trees. The distorted grain in the excrescences,
knobs, or burls, causes the wood from such burls to be prized for
veneers.

BROADLEAF TRUNKS AND WOODS 125

f Fraxinus lanceolata Borkh.
Green Ash. I Fraxinus viridis Michx. f.

( Fraxinus pennsylvanica var . lanceolata Sarg.

NOMENCLATURE (Sud worth).

Green Ash (local and common Ash (Ark., Iowa).

name). Swamp Ash (Fla., Ala., Tex.).

Blue Ash (Ark., Iowa). Water Ash (Iowa).

White Ash (Kans., Neb.).

LOCALITIES.

East of the Rocky Mountains — Vermont and northern Florida, inter-
mittently to Utah and Arizona.

FEATURES OF TREE.

Forty to fifty feet in height; one to two feet in diameter; the upper and
lower surfaces of the smooth leaves are bright green.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish, sap wood lighter; rather coarse-grained; compact

structure.
STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, and strong, but brittle.

REPRESENTATIVE USES OF WOOD.

Similar to those of White Ash (Fraxinus americana).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
39 (United States Forestry Division).1
44.

MODULUS OF ELASTICITY.

2,050,000 (average of 10 tests by United States Forestry Division).1
1,280,000.

MODULUS OF RUPTURE.

11,600 (average of 10 tests by United States Forestry Division.)1
12,700.

REMARKS.

Sometimes considered a variety of Red Ash (Fraxinus pennsylvanica).

1 See p. 33.

126 ORGANIC STRUCTURAL MATERIALS

Oregon Ash. Fraxinus oregona Nutt.

NOMENCLATURE.

Oregon Ash (Gal., Wash., Oregon).

LOCALITIES.

Pacific Coast, British Columbia to southern California.

FEATURES OF TREE.

Fifty to occasionally seventy-five feet in height; one to one and one-half
feet in diameter; the dark grayish-brown bark exfoliates in thin scales.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brown; sap wood lighter; coarse-grained; compact structure;
there are numerous thin medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Rather light and hard, but not strong.

REPRESENTATIVE USES OF WOOD.

Furniture, carriage-frames, cooperage, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

35.
MODULUS OF ELASTICITY.

1,200,000.
MODULUS OF RUPTURE.

9,400.
REMARKS.

One of the valuable deciduous trees of the Pacific Coast. Thrives only
on moist soils and in moist climates.

The Toothache Trees (Xanthoxylum americana and Xanthoxylum dava-
herculis) are known as Ash and Prickly Ash. The Gopher Wood (Cladrastis
tinctoria) is Yellow Ash. These woods are not important.

The name "Mountain Ash" is applied to several species (Sorbus
americana and Sorbus sambucifolia) that yield bright red berries and
soft, light, close-grained, practically valueless woods. The trees are
related to the apple.

BROADLEAF TRUNKS AND WOODS 127

Most trees that yield edible fruits are valued for the fruits, and are
not normally cut in large quantities for wood.

The Apple (Pyrus mains) . These trees originated in Europe, but are
now common in all temperate climates. They are seldom much over
thirty feet in height, and normally afford hard, heavy, close-grained,
brittle woods, that are liable to warp during seasoning. The woods are
suitable for implements and tool handles. Many varieties of Apple
have been perfected by cultivation.1

The Sweet or American Crab Apple Trees (Pyrus coronaria) grow in
many places from Massachusetts and Nebraska southward to Georgia
and Texas. The trees are seldom more than twenty-five feet in height
and one foot in diameter. The hard, close-grained wood is occasionally
used in turnery. The trees are prized in landscape effects because of
their sweet-scented blossoms.

The Oregon Crab Apple (Pyrus rivularis) grows on the Pacific Coast
from California to Alaska and sometimes attains a height of forty feet.
The fine, hard, heavy, close-grained woods are used for mallets and tool
handles. The Narrowleaf Crab Apple (Pyrus augustifolia) yields a
similar wood.

The Pear (Pyrus communis) is widely cultivated in many regions with
temperate climates. The wood, which is rather hard and heavy, is so
firm, fine, tough, and close-grained that it has been used for type, draw-
ing squares, and triangles. It is used in turnery and occasionally in
furniture. Many varieties have been obtained by cultivation.

The Orange (several species, as Citrus aurantium and Citrus trifoliatd)
was introduced into the West Indies, Florida, Louisiana, and California
from Asia and the shores of the Mediterranean. The small trees bear
oily, partially evergreen leaves, fragrant flowers, and edible fruit, which
with oils and essences are highly prized. The strong, hard, heavy, close-
grained, lemon-colored wood is cut into souvenirs and other small ob-
jects. A piece of American Orange wood, exhibited at the St. Louis
Exposition, was ten inches wide. Many varieties of Orange trees have
been obtained by cultivation.

The Olive (Olea europcea). — Olive trees were introduced into southern
California from Asia and the shores of the Mediterranean by the early
Spanish missionaries. The irregularly formed trees, from thirty to
forty feet in height, bear evergreen leaves and valuable oily fruit. The
mottled, rich orange-brown, hard, heavy, close-grained heartwood of
foreign trees is prized for inlaid work, small objects, and souvenirs.
The heartwood of the older trees is the best. American Olive wood is
not particularly attractive because the heartwood has not yet had time
to mature sufficiently. Many varieties of Olive trees have been obtained
by cultivation.

1 "The Apples of New York, " Beach, Booth and Taylor (New York State
Department of Agriculture).

ELM
Ulmus

The several species of Elm are distributed over the eastern
and central portions of the United States. Elm trees are prized
for their fine form and appearance. Because they have no lower
branches, they are particularly good for planting along streets
and near houses. Elm trees attain a high degree of perfection
in some parts of New England.

Elm wood is tough, fibrous, durable, strong, hard, heavy, and
difficult to split and work. It stands well against shocks, and,
for this reason, piles of Elm are useful in ferry slips. The grain
arrangement is often attractive, and the wood is sometimes used
in less important kinds of cabinet work. It is characteristically
employed in piles, flumes, wagons, cars, agricultural implements,
and machinery. The tall, straight trunks yield pieces of con-
siderable size. The wood is used in naval construction from
parts of the largest ships to canoes where it enters the lattice
upon which occupants sit or place their feet. Elm is also used
for carriages upon which heavy cannon are mounted. It is
used in cooperage, floors, pump handles, and trunks. The bark
of the elm tree was used by the Indians in canoes and for rope.

The tree is easily recognized by its form. Fifteen or sixteen
species are known to exist.1

1 See also "The American Elm/' Detwiler (American Forestry, May,
1916).

128

BROADLEAF TRUNKS AND WOODS 129

White Elm. Ulmus americana Linn.

NOMENCLATURE (Sudworth).

White Elm (local and common Pa., N. C., S. C., la., Wis.).

name). American Elm (Vt., Mass., R. I.,

Water Elm (Miss., Tex., Ark., Mo., N. Y., Del., Pa., N. C., Miss.,

111., la., Mich., Minn., Neb.). Tex., III., Ohio, Kans., Neb.,

Elm (Mass., R. I., Conn., N. J., Mich., Minn.).

LOCALITIES.

East of the Rocky Mountains, Newfoundland to Florida, westward
intermittently to the Dakotas, Nebraska, and Texas.

FEATURES OF TREE.

Ninety to one hundred feet in height; three to seven feet in diameter; a
characteristic and beautiful form; smooth buds; the leaves, which are
smaller than those of the Slippery Elm (Ulmus pubescens), are rough
only when rubbed one way.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood light brown; sap wood yellowish white; rather coarse-grained;
annual rings clearly marked.

STRUCTURAL QUALITIES OF WOOD.

Strong, tough, fibrous, and difficult to split.

REPRESENTATIVE USES OF WOOD.

Flooring, wheel-stock, barrel staves, ship-building, flumes, and piles.1

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
34 (United States Forestry Division).2
40.

MODULUS OF ELASTICITY.

1,540,000 (average of 18 tests by United States Forestry Division).2
1,060,000.

MODULUS OF RUPTURE.

10,300 (average of 18 tests by United States Forestry Division).2
12,100.

REMARKS.

The concentration of the foliage at the top, together with their pleasing
form, renders these trees valuable in landscape effects. Elm trees do
not cause dense shade. Elm trees and Silver Maple trees are among
the first to show life in the spring. At that time, discarded brown-
ish scales cover the ground in the vicinity of the trees.

1 See also "White Elm," Pinchot (United States Forest Service, Circular
No. 66, 1907); "The American Elm," Detwiler (American Forestry,
May, 1916).

2 See page 33.

130 ORGANIC STRUCTURAL MATERIALS

~ . „! / Ulmus racemosa Thomas

Cork Elm. s TT7 . _

I Ulmus thomasi Sarg.

NOMENCLATURE (Sudworth).

Cork Elm (local and common Rock Elm (R. I., W. Va., Ky., Mo.

name). 111., Wis., la., Mich., Neb.).

Hickory Elm (Mo., 111., Ind., la.). White Elm (Ont.).

Cliff Elm (Wis.).
LOCALITIES.

Quebec, Ontario, Michigan, and Wisconsin, southward to Connecticut,
northern New Jersey, Ohio, Missouri, and eastern Nebraska.

FEATURES OF TREE.

Seventy to ninety feet in height; two to three feet in diameter; thick,
corky, irregular projections give the bark a characteristic, shaggy
appearance.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown, often tinged with red; sapwood yellowish or
greenish white; compact structure; the fibers interlace.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, very strong, tough, elastic, and difficult to split; receives a
beautiful polish.

REPRESENTATIVE USES OF WOOD.

Heavy agricultural implements, wheel-stock, barrel staves, railway ties,
sills, bridge-timbers, axe-helves, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

45.
MODULUS OF ELASTICITY.

2,550,000.
MODULUS OF RUPTURE.

15,100.
REMARKS.
This is the best of the Elm woods.

BROADLEAF TRUNKS AND WOODS 131

_ _t f Ulmus pubescens Walt.

Slippery Elm, Red Elm. < r,7 ^ , ,,. ,

I Ulmus fulva Michx.

NOMENCLATURE (Sudworth).

Slippery Elm, Red Elm (local and Redwooded Elm (Term.),
common names). Moose Elm (occasional).

Rock Elm (Tenn.).

LOCALITIES.

Ontario and Florida, westward intermittently to Nebraska and Texas;
best developed in the Western States.

FEATURES OF TREE.

Forty-five to sixty feet in height; one to two feet in diameter; characteristic
form; mucilaginous inner bark; the buds are hairy; the leaves are
rough when rubbed either way.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark brown or red; sapwood lighter; compact structure; the
annual layers are marked by rows of large, open ducts; heartwood
greatly preponderates.

STRUCTURAL QUALITIES OF WOOD.
Heavy, hard, strong, and durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.

Largely used for fence-posts, rails, barrel staves, railway ties, sills, sleigh-
runners, and wheel-stock ; the mucilaginous bark is employed in medicine.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

43.
MODULUS OF ELASTICITY.

1,300,000.
MODULUS OF RUPTURE.

12,300.
REMARKS.

132 ORGANIC STRUCTURAL MATERIALS

Wing Elm, Winged Elm. Ulmus alata Michx.

NOMENCLATURE. Mountain Elm, Red Elm (Fla.,
Wing Elm, Winged Elm (local Ark.).

and common names). Elm, Witch Elm (W. Va.).

Wahoo, Whahoo fW. Va., N. C., Water Elm (Ala.).

S. C., La., Tex., Ky., Mo.). Small-leaved Elm (N. C.).

Cork Elm, Corky Elm (Fla., Wahoo Elm (Mo.).

S. C., Tex.).

LOCALITIES.

Southern United States, Virginia, and Florida, westward intermittently to
southern Illinois and Texas.

FEATURES OF TREE.

Forty feet or more in height; one to two feet in diameter; there are corky
"wings" on the branches; the smooth leaves are smaller than those of
the White Elm (Ulmus americand).

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood brownish; sapwood lighter; close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Hard, heavy, tough, and fibrous.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

46.
MODULUS OF ELASTICITY.

740,000.
MODULUS OF RUPTURE.

10,200.
REMARKS.

Not a very common tree.

MAPLE

Acer

Maple trees grow on all the northern continents. Nearly one-
half of the known species are native to Asia. The principal
European species (Acer pseudo-platanus) is known in Europe as a
Sycamore. The Hard or Sugar Maple (Acer saccharum) is one
of the principal deciduous trees of North America.1

Maple wood is noted for its attractive appearance and its fine,
compact structure. Its appearance is so attractive that selected
pieces are classed with the most beautiful of the cabinet woods,
and its structure is so fine and compact that it is sometimes used
for carvings and even for type. Birdseye Maple and Curly
Maple are not separate species, but are results of cellular distor-
tions that may occur, in some form, on other trees as well as
Maples. Birdseye and blister effects are most often seen in the
wood of the Hard Maple (Acer saccharum), while curly effects
are most often seen in the Soft Maples. It is usually impossible
to tell definitely how the woods are figured until the bark is
removed or the trees are cut. Maple wood is tough and strong.
It shrinks moderately and stands well in protected places, but
is not durable when exposed. It is used for flooring, panelling,
furniture, school supplies, implements, machinery, and shoe-
lasts. Sugar is separated from the sap of the Sugar Maple.

The Boxelder (Acer negundo) is a true Maple. The trees are
very beautiful, and, like other Maple trees, are valued for orna-
mental purposes. The soft, light wood is occasionally used for
woodenware, interior finish, and paper pulp. Small quantities
of sugar are present in the sap of this tree.

Maple trees bear two-seeded fruit or "keys;" the parts of
these keys spread differently in different species. The leaves of
some species change from green to red and other brilliant colors in
the autumn. Sixty to seventy species have been distinguished.
Nine of these are native to North America.

1 See also "Beech, Birches and Maples," Maxwell (United States Depart-
ment of Agriculture Bulletin No. 12, 1913:)

133

134 ORGANIC STRUCTURAL MATERIALS

( Acer saccharum Marsh
Sugar Maple. Hard Maple. T . TT.

I Acer sacchannum Wang

NOMENCLATURE (Sudworth).

Sugar Maple, Hard Maple (local Rock Maple (Me., Vt., N. H.,

and common names). Conn., Mass., R. I., N. Y.,

Black Maple (Fla., KyM N. C.). Tenn., 111., Mich., la., Kan.,

Sugar Tree (frequent). Wis., Minn.).

»

LOCALITIES.

Best development Newfoundland to Manitoba. Range extends south-
ward to Florida and Texas.

FEATURES OF TREE.

Seventy to one hundred or more feet in height; one and one-half to four
feet in diameter; the flowers appear with the leaves in the spring; the
fruit or "maple-keys," with wings less than at right angles, ripen in the
early autumn; one seed-cavity in each is usually empty; the leaves
exhibit brilliant reds and other colors in the autumn ; a large, impressive
tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish; sap wood lighter; close-grained; compact structure;
occasional curly, blister, or birdseye effects.

STRUCTURAL QUALITIES OF WOOD.

Tough, heavy, hard, strong, and receives a good polish; wears evenly;
not durable when exposed.

REPRESENTATIVE USES OF WOOD.

Furniture, shoe-lasts, piano-actions, wooden type for showbills, pegs
interior finish, flooring, ship-keels, vehicles, fuel, veneers, rails, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

43.
MODULUS OF ELASTICITY.

2,070,000.
MODULUS OF RUPTURE.

16,300.

REMARKS.1

1 See also "Sugar Maple, Acer saccharum Marsh" (United States Forest
Service, Silvical Leaflet No. 42, 1908). "The Sugar Maple," Detwiler
(American Forestry, November, 1915).

BROADLEAF TRUNKS AND WOODS 135

/ Acer saccharinum Linn.

Silver Maple, Soft Maple. , „,

I Acer dasycarpum E,hr.

NOMENCLATURE (Sud worth).

Silver Maple, Soft Maple (local White Maple (Me., Vt., R. I., N. Y.,

common names). N. J., Pa., W. Va., N. C., S. C.,

Swamp Maple (W. Va., Md.). Ga., Ma., Ala., Miss., La., Ky.,

Water Maple (Pa., W. Va.). Mo., 111., Ind., Kans., Neb.,

River Maple (Me.,.N. H., R. I., Minn.).

W. Va., Minn.).'

LOCALITIES.

New Brunswick to Florida, westward intermittently to the Dakotas and
Oklahama; best development in lower Ohio River basin.

FEATURES OF TREE.

Forty to ninety feet in height, occasionally higher; three to five feet in
diameter; fine form, sometimes suggesting that of the Elm; the maple-
keys, with long, stiff, more than right-angled wings, ripen in the early
summer; the flowers appear before the leaves in the spring; the leaves
exhibit yellows, but seldom reds, in the autumn.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish brown; sapwood ivory white; fine-grained; compact
structure; the fibers are sometimes twisted, waved, or " curly."

STRUCTURAL QUALITIES OF WOOD.

Light, brittle, easily worked, and moderately strong; receives a high polish;
not durable when exposed to the weather.

REPRESENTATIVE USES OF WOOD.

Woodenware, turned work, interior decoration, flooring, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

32.
MODULUS OF ELASTICITY.

1,570,000.
MODULUS OF RUPTURE.

14,400.
REMARKS.

Waving, spiral, or curly figures are pronounced in the woods of this species.

Resemblances to light and shadows are particularly real on planed

surfaces.

136 ORGANIC STRUCTURAL MATERIALS

Red Maple, Swamp Maple. Acer rubrum Linn-

NOMENCLATURE (Sudworth).

Red Maple, Swamp Maple (local Water Maple (Miss., La., Tex., Ky.,

and common names). Mo.).

Soft Maple (Vt., Mass., N. Y., White Maple (Me., N. H.).

Va., Miss., Mo., Kans., Neb., Red Flower (N. Y.).

Minn.).

LOCALITIES.

New Brunswick and Florida, westward intermittently to the Dakotas
and Texas. Wide range.

FEATURES OF TREE.

Sixty to eighty feet and more in height; two and one-half to four feet in
diameter; red twigs and flowers appear before the leaves in the early
spring.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brown, tinged with red; sapwood lighter; close-grained;
compact structure.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and elastic, but not strong; easily worked.

REPRESENTATIVE USES OF WOOD.

Largely used in cabinet-making, turnery, woodenware, and gun-stocks.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

38.
MODULUS OF ELASTICITY.

1,340,000.
MODULUS OF RUPTURE.

15,000.
REMARKS.

The wood occasionally shows a "curly figure."

BROADLEAF TRUNKS AND WOODS 137

Oregon Maple. Acer macrophyllum Pursh.

NOMENCLATURE (Sudworth).

Oregon Maple (Oreg., Wash.). Broad-leaved Maple (Central CalM

White Maple (Oreg., Wash.). Willamette Valley, Ore.).

Maple (Cal.).

LOCALITIES.

Alaska to California; best in rich bottom lands of southern Oregon.

FEATURES OF TREE.

Seventy to one hundred feet in height; three to five feet in diameter;
beautiful appearance; pendant clusters of flowers appear after the leaves
in the spring.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish brown; sapwood whitish; close-grained; compact
structure; occasionally figured.

STRUCTURAL QUALITIES.
Light, hard, and strong; receives a high polish.

REPRESENTATIVE USES OF WOOD.

Locally used for tool-handles, turned work, and furniture.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

30.
MODULUS OF ELASTICITY.

1,100,000.
MODULUS OF RUPTURE.

9,720.
REMARKS.
This ornamental tree has been introduced into Europe.1

also "Manual Trees of North America," Sargent, p. 628.

138 ORGANIC STRUCTURAL MATERIALS

Bozelder, Ash-leaved Maple. ^

I Negundo aceroides Moench.

NOMENCLATURE (Sudworth).

Boxelder, Ash-leaved Maple Stinking Ash (S. C.).

(local and common names). Negundo Mapie (HI.).

Red River Maple, Water Ash Three-leaved Maple (Fla.).

(Dak.). Black Ash (Term.).

Cut-leaved Maple (Colo.). Sugar Ash (Fla.).

LOCALITIES.

Atlantic Ocean, westward intermittently to Rocky Mountains and
Mexico.

FEATURES OP TREE.

Forty to seventy feet in height; one and one-half to three feet in diameter;
the wings to the keys are straight or incurved; the leaves exhibit yel-
lows, but seldom reds, in the autumn; the flowers appear with or before
the leaves in the spring.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thin heartwood, cream white; sapwood similar; close-grained; compact
structure.

STRUCTURAL QUALITIES OF WOOD.
Light and soft; not strong.

REPRESENTATIVE USES OF WOOD.

Woodenware, cooperage, paper-pulp, and occasionally interior finish.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

26.
MODULUS OF ELASTICITY.

82,000.
MODULUS OF RUPTURE.

7,500.
REMARKS.

The Boxelders withstand severe climatic changes, grow rapidly and are
good trees to plant in many otherwise treeless sections. Sugar is
sometimes obtained from the sap of this species. See also "Boxelder"
(United States Forest Service Circular No. 86).

WALNUT

Juglans

The English or Royal Walnut (Juglans regia) is the principal
species in Europe, while the Black Walnut (Juglans nigrd), and
the Butternut or White Walnut (Juglans tinerea) grow in the
United States. Botanically, Circassian Walnut is the same as
English, Royal, or European Walnut. English Walnut is the
name used almost exclusively by those who grow the tree for its
nuts, while Circassian Walnut is the name usually applied to the
wood.1

The English Walnut was introduced from Asia into Greece and
Italy, and, through these countries, into others. It is cultivated
in the United States, but principally for its nuts. The appear-
ance and desirability of the wood differ with localities. Pieces
cut from English trees are said to be paler and coarser than those
cut from Italian and French trees. Ordinary pieces exhibit
large open figures, with waves and streaks of gray and yellowish-
white, while exceptional excrescences known as burrs, which are
sometimes two or three feet across, yield figured woods of great
beauty. Circassian Walnut is very valuable, and is now used
almost exclusively in costly decorations, piano cases, and high-
grade furniture. No other wood is better for gun-stocks, and,
until the battle of Waterlo, othe demand in Europe for this pur-
pose was so great that as much as six hundred pounds sterling
is said to have been paid for a single tree.

At the present time (1917) the supply of Black Walnut for making
stocks for military rifles is ample. A manufacturer writes as follows:
"At the beginning of the great war (1914) we were under the im-
pression that we might experience some difficulty in securing sufficient
of this wood; but we have had no such trouble, in fact, we have had
much more of it offered to us than we require."

American or Black Walnut was once very popular, in the
United States, as a cabinet wood. The trees are now scarce;
lighter colored Woods are preferred, and, at present, walnut is
seldom seen save in gun-stocks and old furniture. The figures
that characterize pieces of Circassian Walnut are absent in the

139

140 ORGANIC STRUCTURAL MATERIALS

darker, more uniformly tinted American woods. Black Walnut
trees seldom form forests by themselves, but are usually found
mixed with those of other species. They grow rapidly, but the
valuable heartwood does not mature until a number of years
after the trees have been planted.

Small pieces of dark, rich brown wood are obtained from the
Mexican or Arizona Walnut (Juglans rupestris), which grows in
some of the sparsely settled regions of the Southwest, where it is
also known as the Western, Dwarf, Little, and California Walnut.
The true California Walnut (Juglan calif or nica) is found on the
Pacific Coast from the Sacramento River to the San Bernardino
Mountains, and sometimes attains diameters of fifteen inches.
The blue-brown woods can be, but seldom are, used in cabinet
making. The White Walnut or Butternut (Juglans cinerea) yields
a rather soft, light, grayish-brown heartwood that is sometimes
used in cabinet making.

Walnut trees may be known by their nuts. The husks or
pods are not quartered as in the case of the hickories.

1 "Circassian Walnut," Sudworth and Mell (United States Forest Service,
Circular No. 212).

BROADLEAF TRUNKS AND WOODS 141

Circassian Walnut, European Walnut. Juglans regia

NOMENCLATURE (Sudworth and Mell).

Circassian Walnut, European Walnut, Russian Walnut.

English Walnut, Royal Walnut (local Turkish Walnut.

and common names). Nogal (Spain, Cuba, and

Persian Walnut. South America).

French Walnut. Ancona Auvergne (Italy).

Italian Walnut. Noyer (France).

Austrian Walnut. •

LOCALITIES.

Widely planted on all of the continents.

FEATURES OF TREE.

About 40 feet in height; attractive in appearance.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood dark chocolate brown, tints sometimes extending from light
brown to black; sapwood lighter; beautiful veins and figures, particularly
in the wood of older trees; fine, close grain.

STRUCTURAL QUALITIES OF WOOD.

Moderately hard, moderately heavy; splits but little in seasoning; the
sapwood is liable to become worm-eaten.

REPRESENTATIVE USES OF WOOD.

Circassian Walnut was formerly used in turnery, toys, carved work,
carpentry, wooden shoes, and gun-stocks. The wood is now scarce
and is only employed in the most costly furniture and cabinet work.

WEIGHTS OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
MODULUS OF ELASTICITY.
MODULUS OF RUPTURE.

REMARKS.

For many years the demands for this wood have been greater than the
supply. Among the related woods which have been used as substi-
tutes are the Caucasian Walnut (Pterocarya caucasica)1, the West
Indian Walnut (Juglans insularis), the Nogal (Juglans australis), and
the Butternut (Juglans cinered). The Red Gum (Liquidambar styra-
ciflua), which is sometimes called the Satin Walnut, is often handsomely
veined, and is then very similar to true Circassian Walnut.

1 The similarity of names is such that Caucasian Walnut and Circassian
Walnut are sometimes confused with one another. The wood of the former
lacks the veining which characterizes the latter.

142 ORGANIC STRUCTURAL MATERIALS

Black Walnut. Juglans nigra Linn.

NOMENCLATURE (Sudworth).

Black Walnut (local and common name). Walnut (N. Y., Del., W. Va.,

Fla., Ky., Mo., Ohio, Ind., la.).
LOCALITIES.

Ontario and Florida, westward intermittently to Nebraska and Texas.

FEATURES OP TREE.

Ninety to one hundred and twenty-five feet in height; three to eight feet
in diameter; a tall, handsome tree with rough, brownish, almost black,
bark ; the compound leaves are composed of from thirteen to twenty-
three leaflets; the nuts are large and rough-shelled.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood rich, dark, chocolate brown; the thin sapwood is much lighter
in color; rather coarse-grained.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, strong, easily worked, and durable; receives a high polish.

REPRESENTATIVE USES OF WOOD.

Cabinet-making and gun-stocks; also formerly furniture and decoration.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

38.
MODULUS OF ELASTICITY.

1,550,000.
MODULUS OF RUPTURE.

12,100.
REMARKS.

This tree is now somewhat rare in the Eastern parts of the United States.1

See also "Handbook Trees of Northern States and Canada," Hough.

BROADLEAF TRUNKS AND WOODS 143

Butternut, White Walnut. Juglans cinerea Linn.

NOMENCLATURE.

Butternut, White Walnut (local Walnut (Minn.).

and common names). White Mahogany.

Oil Nut (Me.,. N. H., S. C.).

LOCALITIES.

New Brunswick to Georgia, westward to Dakota and Arkansas; best in
Ohio River basin.

FEATURES OP TREE.

Medium size, sometimes seventy-five feet or over in height; two to four
feet in diameter; the branches are widespread; the compound leaves a re
composed of from eleven to seventeen leaflets; there are large-sized,
oblong, edible nuts.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light gray-brown, darkening with exposure; sapwood nearly
white; coarse-grained; compact structure; an attractive wood.

STRUCTURAL QUALITIES OP WOOD.

Light, soft, and easily worked, but not strong; receives a high polish.

REPRESENTATIVE USES OP WOOD.

Interior finish and cabinet-work. The inner bark furnishes a yellow dye.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

25.
MODULUS OF ELASTICITY.

1,150,000.
MODULUS OP RUPTURE.

8,400.

REMARKS.1

also "Handbook Trees of Northern States and Canada," Hough.

HICKORY

Hicoria

The Hickories grow in the temperate regions of eastern North
America, and eastern Asia.

The woods, which are noted for strength, toughness, flexibility,
and resilience, are used for handles, implements, machinery
and carriage parts. Axe handles and hammer handles of this
wood have no superiors. The reputation of American axes and
hammers owes much to the qualities of these handles. The
properties that render Hickory valuable are most pronounced in
the sapwood, which, in this species, is more desirable than the
heartwood. Second growth Hickory is prized, since, being
younger, it contains more of the pliable sapwood. Hickory does
not last well in exposed positions.

The genus includes about a dozen species. The Hickories
may be distinguished from the Walnuts by the nuts. In most
cases, the nuts of the Hickories are covered with husks that
divide into four parts, while those' of the Walnuts remain un-
broken.1

1 See also "The Commercial Hickories," Boisen and Newlin (United
States Forest Service, Bulletin No. 80, 1910); "Manufacture and Utiliza-
tion of Hickory," Hatch (United States Forest Service, Circular No. 187,
1911).

144

BROADLEAF TRUNKS AND WOODS 145

f Hicoria ovata Mill.
Shagbark ttckory, Shellbaik Hackory, (

Shagbark.

NOMENCLATURE (Sudworth).

Shagbark or Shellbark Hickory Hickory (Vt., Ohio).

(local and common names). Upland Hickory (111.).

Scalybark Hickory (W. Va., S. C., White Hickory (la., Ark.).

Ala.). Walnut (Vt., N. Y.).

Shellbark (R. I., N. Y., Pa., N. C.). Sweet Walnut (Vt.).

Shagbark (R. I., Ohio). Shagbark Walnut (Vt.).

LOCALITIES.

Quebec to Florida, westward intermittently to Minnesota and Texas.
Wide range, best in Ohio Valley.

FEATURES OP TREE.

Seventy-five to ninety feet in height, occasionally higher; two and one-
half to three feet in diameter; shaggy bark; the compound leaves are
composed of five and, rarely, seven leaflets; there are thin-shelled,
edible nuts.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown; sapwood ivory white or cream colored; close-
grained; compact structure; the annual rings are clearly marked; the
medullary rays are numerous but thin.

STRUCTURAL QUALITIES OF WOOD.

Very heavy, very hard, strong, exceptionally tough and flexible; not
durable when exposed.

REPRESENTATIVE USES OF WOOD.

Largely used for agricultural implements, wheels, runners, axe handles,
baskets, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
51 (United States .Forestry Division).1
52.

MODULUS OF ELASTICITY.

2,390,000 (average of 137 tests by United States Forestry Division).1
1,900,000.

MODULUS OF RUPTURE.

16,000 (average of 137 tests by United States Forestry Division).1
17,000.

REMARKS.

The nuts form an important article of commerce. "Shagbark" refers to
the shaggy appearance of the bark.2

1 See p. 33.

2 See also "Shagbark Hickory" (United States Forest Service, Circular
No. 62, 1907).

146 ORGANIC STRUCTURAL MATERIALS

Pignut. Hicoria glabra Mill.

Gary a porcina Nutt.

NOMENCLATURE (Sudworth).

Pignut (local and common name). White Hickory (N. H., la.).

Black Hickory (Miss., La., Ark., Broom Hickory (Mo.).

Mo., Ind., la.). Hardshell (W. Va.).

Brown Hickory (Del., Miss., Red Hickory (Del.).

Tex., Tenn., Minn.). Switchbud Hickory (Ala.).
Bitternut (Ark., 111., la., Wis.).

LOCALITIES.

Maine to Florida, westward intermittently to southern Nebraska and
eastern Texas.

FEATURES OF TREE.

Seventy-five to one hundred feet in height, occasionally higher; two to
four feet in diameter; rather smooth bark; the compound leaves are
composed of from three to seven leaflets; the large, thick-shelled nuts
contain kernels that are often astringent or bitter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light and dark brown; the thick sapwood is lighter; close-
grained.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, flexible, tough, and strong.

REPRESENTATIVE USES OF WOOD.
Similar to those of Shagbark Hickory (Hicoria ovata).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
56 (United States Forestry Division).1
51.

MODULUS OF ELASTICITY.

2,730,000 (average of 30 tests by United States Forestry Division.)1
1,460,000.

MODULUS OF RUPTURE.

18,700 (average of 30 tests by United States Forestry Division.)1
14,800.

REMARKS.2

1 See p. 33.

2 See also "Pignut Hickory, Hicoria glabra (Mill.)" Britton (United

States Forest Service, Silvical Leaflet No. 48, 1909).

BROADLEAF TRUNKS AND WOODS 147

f Hicoria alba Linn.
Mocker Nut. j Carya tomentosa NuiL

NOMENCLATURE (Sudworth).

Mocker Nut, Whiteheart Hick- Big-bud, Red Hickory (Fla.).

ory (local and common names). Common Hickory (N. C.).

Bullnut (N. Y., Fla., Miss., White Hickory (Pa., S. C.).

Tex., Mo., Ohio, 111., Minn.). Hickory Nut (Ky., W. Va.).

Black Hickory (Tex., Miss., La., Hog Nut (Del.).

Mo.). Hard bark Hickory (111.).
Hickory (Ala., Tex., Pa., S. C.,

Neb.).

LOCALITIES.

Ontario to Florida, westward intermittently to Missouri and Texas.
Wide range.

FEATURES OF TREE.

Seventy-five to one hundred feet in height; two and one-half to three and
one-half feet in diameter; a tall, slender tree with rough, but not shaggy,
bark; the compound leaves are composed of from five to nine leaflets;
there are thick-shelled, edible nuts.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood rich, dark brown; the thick sapwood is nearly white; close-
grained.

STRUCTURAL QUALITIES OP WOOD.

Very heavy, hard, tough, strong, and flexible.

REPRESENTATIVE USES OP WOOD.
Similar to those of Shagbark Hickory (Hicoria ovata).

WEIGHT OP SEASONED WOOD IN POUNDS PER CUBIC FOOT.
53 (United States Forestry Division).1
51.

MODULUS OF ELASTICITY.

2,320,000 (average of 75 tests by United States Forestry Division).1
1,630,000.

MODULUS OP RUPTURE.

15,200 (average of 75 tests by United States Forestry Division).1
16,000.

REMARKS.

The most generally distributed species of the genus in the South

1 See p. 33.

148 ORGANIC STRUCTURAL MATERIALS

p / Hicoria pecan Marsh

I Carya olivceformis Nutt.

NOMENCLATURE (Sud worth).

Pecan (local and common name).
Pecan Nut, Pecan-tree, Pecanier (La.).

LOCALITIES.

Valley of Mississippi, southward to Louisiana and Texas.

FEATURES OF TREE.

Ninety to one hundred feet in height, sometimes higher; two and one-half
to five feet in diameter; a tall tree; the compound leaves are composed of
from nine to fifteen leaflets; there are smooth-shelled, oblong, edible
nuts.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light-brown, tinged with red; sapwood lighter brown; close-
grained and compact; the medullary rays are numerous, but thin.

STRUCTURAL QUALITIES OF WOOD.

Heavy and hard, but not strong and brittle.

REPRESENTATIVE USES OF WOOD.
Fuel; seldom used in construction.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
49 (United States Forestry Division).1
44.

MODULUS OF ELASTICITY.

2,530,000 (average of 37 tests by United States Forestry Division).1
940,000.

MODULUS OF RUPTURE.

15,300 (average of 37 tests by United States Forestry Division).1
8,200.

REMARKS.

Grows on borders of streams in low, rich soil. It is the largest and most
important tree of Western Texas. The sweet, edible nuts form an
important article of commerce.

1 See p. 33.

CHESTNUT, CHINQUAPIN

Castanea

These trees grow in many parts of eastern North America,
southern Europe, northern Africa, western Asia, and parts of
China and Japan.

European Chestnut wood was once held in high regard. It
should be noted, however, that some of the constructions, in
which this wood was thought to exist, were actually built of oak.
The wood of the North American Chestnut (Castanea vulgaris),
which is weak, brittle, easily worked, and very durable, is one of
the best of those used for fence posts, and mud sills, where dura-
bility rather than great strength is required. Hough mentions a
Chestnut fence-rail that was good after having been exposed for
about one hundred years.

The chestnut bark disease now tentatively named Diaporthe para-
sitica Murrill1 was first detected in New York City parks in 1904.
Seventeen thousand trees soon succumbed in one park alone (Forest
Park, Brooklyn). The disease, which was probably introduced from
Japan, is conveyed by winds and insects, and no tree once attacked
ever recovers. The value of the trees thus far destroyed is very great
and the prospective losses are enormous.2

The name Chinquapin applies to two North American species :
the Common Chinquapin (Castanea pumila) grows in the Central
and Southeastern States; while the Western, Goldenleaf, or
California Chinquapin, or "Evergreen Chestnut," (Castanopsis
chrysophylla) grows on the Pacific Coast. Both of these species
afford woods that resemble ordinary chestnut.

The American Chestnut (Castanea vulgaris) is known by its
large, prickly burrs that contain from one to three thin-shelled,
triangular, wedge-shaped, edible nuts. The Chinquapins bear
prickly burrs that hold one, or occasionally two, sweet edible
nuts.

1 Some botanists believe that this blight is Endothia gyrosa, while others
characterize it as Endothia gyrosa var. parasitica.

2 See also Journal of New York Botanical Garden (Vol. II, p. 143) ; also,
Marlatt (National Geographic Magazine, April, 1911); "Report of Chest-
nut Tree Blight," Mickleborough (Pennsylvania State Department of
Forestry); etc.

149

150 ORGANIC STRUCTURAL MATERIALS

(Castanea dentata (Marsh) Borkh.
Castanea vesca var. americana Michx.
Castanea vulgaris var. americana A. de C.
NOMENCLATURE.

Chestnut (local and common name).

LOCALITIES.

New England, Ontario, and New York to Georgia, Alabama, and Missis-
sippi; also Kentucky, Missouri, and Michigan ; best on the Western slope
of the Alleghany Mountains.

FEATURES OF TREE.

Seventy-five to one hundred feet in height; five to twelve feet in diameter ;
a fine, characteristic shape, not easily distinguished from that of the
Red Oak (Quercus rubra) in winter; the trees blossom in midsummer;
the prickly burrs contain three, exceptionally five, thin-shelled nuts.1

COLOR, APPEARANCE OR GRAIN OF WOOD.

Heart wood brown; sap wood lighter; coarse-grained.

STRUCTURAL QUALITIES OF WOOD.

Light and soft; not strong; liable to check and warp in drying; easily split;
very durable in exposed positions.

REPRESENTATIVE USES OF WOOD.

Cabinet-making, railway ties, posts, fencing, and sills.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,200,000.
MODULUS OF RUPTURE.

9,800.
REMARKS.
In the eastern part of the United States, chestnut trees have been attacked

by a fungus (tentatively named Diaporthe parasitica),2 which (1913)

is apparently destroying all of the chestnut forests.

1 See also "Chestnut," Pinchot (United States Forest Service, Circular
No. 71, 1907); "The American Chestnut Tree," Detwiler (American
Forestry, October, 19 15); etc.

2 As stated elsewhere, some botanists believe that this blight should be
characterized as Endothia gyrosa or Endothia gyrosa var. parasitica.

BROADLEAF TRUNKS AND WOODS 151

Chinquapin. Castanea pumila (Linn.} Mill.

NOMENCLATURE (Sudworth).

Chinquapin (Del., N. J., Pa., Va., W. Va., N. C., S. C., Ga., Ala., Fla.,
Miss., La., Tex., Ark., Ohio, Ky., Mo., Mich.).

LOCALITIES.

Pennsylvania and New Jersey to Florida, Mississippi, Louisiana, Texas,
Arkansas, Ohio, Kentucky, Missouri, and Michigan.

FEATURES OF TREE.

A small tree, sometimes forty-five feet in height; one to two feet or over
in diameter; sometimes a low shrub; can be distinguished from the
Chestnut (Castanea dentata} by the fact that the leaves are smooth on
both sides; the small, prickly burrs contain single, small chestnut-col-
ored nuts.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark brown; sapwood hardly distinguishable; coarse-grained;
the annual layers are marked by rows of open ducts.

STRUCTURAL QUALITIES OF WOOD.

Rather heavy, hard, and strong; durable in exposed positions; liable to
check in drying.

REPRESENTATIVE USES OF WOOD.
Posts, rails, railway ties, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

36.
MODULUS OF ELASTICITY.

1,620,000.
MODULUS OF RUPTURE.

14,000.
REMARKS.

This tree is more suitable for planting in parks than as a source of lumber.

The Chinquapin (Castanopsis chrysophylla} is a tree with characteristics
which are between those of the Oak and Chestnut. Its wood, which is nearly
similar to that of the Chinquapin (Castanea pumila}, is sometimes used for
implements. It is native in Oregon and California.

BEECH

Fagus

The Beeches are represented in the temperate regions of the
northern hemisphere by a single species (Fagus americana). The
European Beech (Fagus sylvatica) is an important tree abroad.1

Beech wood is hard, heavy, strong, fine-grained, not durable
when exposed, and somewhat subject to attack by insects.
European Beech is employed to a considerable extent in construc-
tion and turnery, and is used more than almost any other local
wood for fuel. Beech possesses almost all of the properties that
are valued in construction, save durability in exposed positions;
in Europe, this deficiency is corrected by artificial means. Beech
responds more completely than Oak to treatment with anti-
septics, and the French secure longer service from many treated
Beech ties, than Americans secure from many treated Oak ties.

Beech trees are covered with smooth, light-colored bark.
They produce small prickly burrs, each of which contains two
triangular, sharp-edged nuts, which are sometimes referred to as
beech-mast, and which yield an oil that is occasionally used in
place of olive oil. The nuts are not gathered to any extent in the
United States.

The Coffee, Coffeenut, Coffeebean, Coffeebean-tree, or
Mahogany (Gymnocladus dioicus). — These trees grow best
between the Alleghany Mountains and the Mississippi River.
They are valued in landscape effects, and, in many places, are
cultivated. The strong, durable, reddish-brown wood works
easily, polishes well, and can be used in cabinet work.

The Hackberry, Sugarberry, One-berry, Nettle-tree, or
False Elm (Celtis occidentalis) . — This tree is occasionally found
between Canada and Florida and between the Atlantic Coast and
the Rocky Mountains. Isolated specimens are sometimes locally
famed as " Unknown Trees." The rather hard, strong wood is
occasionally used in fencing andjn cheap furniture.2

1 See also "Beech, Birches and Maples," Maxwell (United States Depart-
ment of Agriculture, Bulletin No. 12, 1913).

2 See also "Hackberry," Pinchot (United States Forest Service, Circular
No. 75, 1907).

152

BROADLEAF TRUNKS AND WOODS 153

Fagus americana Sweet

Fagus grandifolia

Fagus atropunicea (Marsh} Sudworth

Fagus ferruginea Ait.

NOMENCLATURE (Sudworth). White Beech (Me., Ohio, Mich.).

Beech (local and common name). Ridge Beech (Ark.).
Red Beech (Me., Vt., Ky., Ohio).

LOCALITIES.

Nova Scotia to Florida, westward intermittently to Wisconsin and Texas.

FEATURES OF TREE.

Sixty to eighty feet in height, occasionally higher; two to four feet in diame-
ter; the small, rough burrs contain two thin-shelled nuts.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish, variable shades; sapwood white; rather close-grained;
conspicuous medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Hard, strong, and tough; not durable when exposed; liable to check during
seasoning; takes a fine polish.

REPRESENTATIVE USES OF WOOD.

Shoe-lasts, plane-stocks, ship-building, handles, and fuel; carpentry
(abroad), wagon-making, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

42.
MODULUS OF ELASTICITY.

1,720,000.
MODULUS OF RUPTURE.

16,300.
REMARKS.

There is but one species of Beech in North America. The wood is
occasionally divided into "Red Beech" and "White Beech," according
to its color. This division has no botanical basis, since both of these
woods come from the same tree.

154 ORGANIC STRUCTURAL MATERIALS

Ironwood, Blue Beech. Carpinus caroliniana Walt.

NOMENCLATURE (Sudworth).

Ironwood, Blue Beech (local and Hornbeam (Me., N. H., Mass.,

common names). R. I., Conn., N. Y., N. J., Pa.,

Water Beech (R. I., N. Y., Pa., Del., N. C., S. C., Ala., Tex.,

Del., W. Va., Ohio, 111., Ind., Ky., 111., Kans., Minn.).

Mich., Minn., Neb., Kans.).

LOCALITIES.

Quebec to Florida, westward intermittently to Nebraska and Texas.

FEATURES OF TREE.

Thirty to fifty feet in height; six inches to occasionally two feet in di-
ameter; a small tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown; thick sapwood nearly white; close-grained.

STRUCTURAL QUALITIES OF WOOD.

Very hard, tough, strong, and heavy; very stiff; inclined to check during
seasoning; not durable when exposed.

REPRESENTATIVE USES OF WOOD.
Levers, tool-handles, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

45.
MODULUS OF ELASTICITY.

1,630,000.
MODULUS OF RUPTURE.

16,300.
REMARKS.

The name Ironwood is also applied to the Hornbeam (Ostrya virginiana),
and to some other North American species that afford unusually hard,
heavy woods suitable for handles and implements. The trunks of the
species known as Ironwoods are generally small.

BROADLEAF TRUNKS AND WOODS 155

Ironwood, Hop Hornbeam. Ostrya virginiana Willd.

NOMENCLATURE (Sudworth).

Ironwood, Hop Hornbeam (local Hornbeam (R. I., N. Y., Fla., S. C.,

and common names). La.).

Leverwood (Vt., Mass., R. I., Hardback (Vt.).
N. Y., Pa., Kans.).

LOCALITIES.

Nova Scotia to Florida, westward intermittently to North Dakota, South
Dakota, and Texas.

FEATURES OF TREE.

Thirty to forty feet in height; one foot or less in diameter; the bark ex-
hibits long, vertical rows of small squares; small fruit suggest hops in
appearance; the leaves resemble those of the Birch.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood reddish brown, sometimes white; sap wood lighter or white;
close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Very strong, hard, heavy, and tough; durable when exposed.

REPRESENTATIVE USES OF WOOD.

Posts, levers, tool-handles, axe-helves, mill-cogs, and wedges.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

51.
MODULUS OF ELASTICITY.

1,950,000.
MODULUS OF RUPTURE.

16,000.
REMARKS.
Trees over twelve inches in diameter are often hollow.

SYCAMORE

Platanus

The name Sycamore applies to a Maple (Acer pseudo-platanus)
in Europe, to a Fig tree (Ficus sycomorus) in the Orient, and to
the Buttonball or Plane trees (Platanus) in North America. Of
the Sycamore or Plane trees, the Common or Oriental Plane
(Platanus orientalis) is a native of Europe; the Plane, Buttonball,
or Sycamore tree (Platanus occidentalis) is a native and common
tree of eastern North America; and the California Sycamore
(Platanus racemosa) is a native of western North America.1

American sycamore wood is tough, strong, and difficult to
split. The cellular structure is complicated, and a typical use of
the wood is for butcher's blocks. Because of its beauty, quar-
tered sycamore is used in cabinet work and indoor finish.

American Plane, Buttonball, or Sycamore trees are distin-
guished by rough heads or balls, which remain hanging on long
stems throughout the winter. The bark is also characteristic.
Large flakes of the outer bark drop away and expose inner sur-
faces, so smooth and white that they appear to be painted. Six
or seven species are included in this genus. Three of the species
occur in North America.

1 The sycamore possesses an emblematic interest because of its biblical
association with Zaccheus. Many European sycamores were planted by
religious persons during the Middle Ages because of the belief that they
were the trees referred to in the Bible.

156

BROADLEAF TRUNKS AND WOODS 157

Sycamore, Buttonwood, Buttonball-tree. Platanus occidentalis Linn.

NOMENCLATURE (Sudworth).

Sycamore, Buttonwood, Button- Plane Tree (R. I., Del., S. C., Kans.,

ball-tree (local and common Neb., la.).

names). Water Beech (Del.).

Buttonball (R. I., N. Y., Pa., Platane, cotonier, Bois puant (La.).

Fla.).

LOCALITIES.

Maine and Ontario to Florida, westward intermittently to Nebraska and
Texas; best in the bottom lands of the Ohio and Mississippi River
basins.

FEATURES OF TREE.

Ninety to over one hundred feet in height; six to sometimes twelve feet
in diameter; the inner bark is exposed in white patches; the rough balls
or heads are about one inch in diameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood reddish-brown; sap wood lighter; close-grained; compact
structure; satiny; conspicuous medullary rays; the wood is attractive
when quartered.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and difficult to work; not strong; stands well when not
exposed.

REPRESENTATIVE USES OF WOOD.

Tobacco-boxes, ox-yokes, butcher-blocks, and cabinet-work.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

35.
MODULUS OF ELASTICITY.

1,220,000.
MODULUS OF RUPTURE.

9,000.
REMARKS.

Some specimens are among the largest of American deciduous trees, but
the bottoms of such exceptionally large trees are usually hollow. The
bark is thin and soft when the tree is young but becomes thicker and
harder as the tree grows older, until a point is reached when it can no
longer stretch to accommodate the growth of the tree. Large areas of
the bark are then thrown off by the tree and the inner surfaces which are
exposed appear so smooth and white as to suggest the possibility that
they have been painted.

158 ORGANIC STRUCTURAL MATERIALS

California Sycamore. Platanus racemosa Nutt.

NOMENCLATURE.

Sycamore, Button wood, Buttonball Tree, Buttonball (California).

LOCALITIES.

California and Lower California.

FEATURES OP TREE.

Seventy-five to one hundred feet in height, occasionally higher; three to
four feet in diameter; differs from the Sycamore (Platanus occidentalis)
in that the balls or heads are in clusters and not solitary; the bark exfo-
liates in irregular patches.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light reddish brown; sapwood lighter; close-grained; compact
structure; the medullary rays are numerous and conspicuous; the wood
is quite attractive when quartered.

STRUCTURAL QUALITIES OF WOOD.

Brittle, very difficult to split and season; the qualities are similar to those
of the Sycamore (Platanus occidentalis) .

REPRESENTATIVE USES OF WOOD.

Decoration and furniture; used as the wood of the Sycamore (Plalanus
occidentalis) is used.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

30.
MODULUS OF ELASTICITY.

800,000.
MODULUS OF RUPTURE.

7,900
REMARKS.

BIRCH

Betula

Birch trees grow in many places in North America, Europe,
and Asia. The ranges of some species extend far into the North.
Birch trees are noted for their bark, quite as much as for their
wood.1

The Paper Birch (Betula papyrifera) is the species that is
most noted for its bark, which is smooth, pliable, inflammable,
water-tight, of a cream or ivory-white color, and marked with
long, horizontal, raised dashes or lenticels. The bark contains
resinous oils and is so durable that it often remains intact on
fallen trees, long after the wood inside has rotted and disappeared.
The layers, of which it is composed, separate easily from one
another and can be obtained in large-sized pieces. The North
American Indians employed it for canoes, tents, troughs, and
buckets. It has also been used to write upon and to cover
houses.

The Yellow Birch (Betula lutea) and the Sweet Birch (Betula
lento) are prized for their hard, heavy, strong, fine-grained, and
attractive woods, which, however, are not durable in exposed
positions. These woods are used in spools, woodenware, in-
terior finish, and furniture. They are often stained so as to
imitate cherry and mahogany. One of the best of the "imita-
tion mahoganies" is obtained by staining Birch. The European
Birch (Betula alba) yields the cheapest native hardwood obtain-
able in many parts of Europe. This wood, which is moderately
hard and strong, but not durable, is used for furniture, plates,
spoons, sabots, and similar objects. The Russians glue rotary-
cut veneers of birch across one another and form thin, rigid
planks that are used for tea-chests and chair-bottoms. Occa-
sional burrs yield figured woods that are turned into cups, bowls
and mallets.

1 See also " Beech, Birches and Maples," Maxwell (United States De-
partment of Agriculture Bulletin No. 12, 1913); "The Birches," Detwiler
(American Forestry, April, 1916).

159

160 ORGANIC STRUCTURAL MATERIALS

White Birch. Betula populifolia Marsh

NOMENCLATURE (Sudworth). Oldfield Birch, Poverty Birch (Me.).

White Birch (local and common Poplar-leaved Birch, Small White

name). Birch (Vt.).
Gray Birch (Me., R. I., Mass.).

LOCALITIES.

Atlantic Coast, Canada to Delaware and Kentucky.

FEATURES OF TREE.

Twenty to forty feet in height; rarely one foot in diameter; durable, lam-
inated, smooth white bark on the large branches and on the trunk, save
near the ground; the bark is not very easily detached from the tree.

COLOR, GRAIN, OR APPEARANCE OF WOOD.

Heartwood light brown; sapwood lighter; close-grained.

STRUCTURAL QUALITIES OF WOOD.
Soft and light; not strong or durable.

REPRESENTATIVE USES OF WOOD.

Clothes-pins, shoe-pegs, toothpicks, and paper-pulp.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

35.
MODULUS OF ELASTICITY.

1,036,000.
MODULUS OF RUPTURE.

11,000.
REMARKS.

The white bark is distinct from that of the Paper Birch (Betula papyrifera)
in that it does not cover the whole trunk. The layers split less easily
from one another.

BROADLEAF TRUNKS AND WOODS 161

Paper Birch, White Birch. Betula papyrifera Marsh

NOMENCLATURE (Sud worth).

Paper Birch, White Birch (local Boleau (Quebec).

and common names). Canoe Birch (Me., Vt., N. H., R. I.,

Silver Birch (Minn.). Mass., N. Y., Pa., Wis., Mich.,

Large White Birch (Vt.). Minn.).

LOCALITIES.

Northern United States, northward into Canada and to the valley of the
Yukon in Alaska.

FEATURES OF TREE.

Fifty to seventy feet in height; one and one-half to two and one-half
feet in diameter; smooth white exterior bark on large limbs and on
trunks at a distance from the ground; brown or orange-colored inner
surfaces of bark; the bark splits freely into thin, paper-like layers.

COLOR, GRAIN, OR APPEARANCE OF WOOD.

Heartwood brown, tinged with red; sapwood nearly white; very close-
grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Strong, hard, and tough; is not durable when exposed to the weather;
the bark takes fire easily, even when it is wet.

REPRESENTATIVE USES OF WOOD.

Spools, shoe-lasts, pegs, pill-boxes, paper-pulp, and fuel; the bark was used
in canoes.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

37.
MODULUS OF ELASTICITY.

1,850,000.
MODULUS OF RUPTURE.

15,000.
REMARKS.

These trees grow at higher latitudes than most other American deciduous
trees. They form forests.1

1 See also "Paper Birch, Betula papyrifera Marsh" (United States Forest
Service, Silvical Leaflet No. 38, 1908).
11

162 ORGANIC STRUCTURAL MATERIALS

Red Birch. Betula nigra Linn.

NOMENCLATURE (Sudworth).

Red Birch (local and common River Birch (Mass. R. I., N. J.,
name). Del., Pa., W. Va., Ala., Miss.,

Black Birch (Fla., Tenn., Tex.). Tex., Mo., 111., Wis., Ohio).

Birch (N. C., S. C., Miss., La.). Water Birch (W. Va., Kans.).

Blue Birch (Ark.).
LOCALITIES.

Massachusetts to Florida, westward intermittently to Nebraska and
Texas; best development in South Atlantic and lower Mississippi valley
regions.

FEATURES OF TREE.

Thirty to eighty feet in height; one to three feet in diameter, sometimes
larger; dark red-brown scaly bark on trunk; red to silver-white bark on
branches; the bark separates into thin, paper-like scales, which curl
outward.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood light brown; sapwood yellowish white; close-grained, com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, rather hard, and strong.

REPRESENTATIVE USES OF WOOD.

Furniture, wooden ware, shoe-lasts, and ox-yokes; inferior cask -hoops are
made from the branches; also used as a base upon which enamelled
paints are applied.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

35.
MODULUS OF ELASTICITY.

1,580,000.
MODULUS OF RUPTURE.

13,100.
REMARKS.

Dark-brown bark, whence the name Red Birch. Prefers moist bottoms,
whence the name River Birch.

BROADLEAF TRUNKS AND WOODS 163

Yellow Birch. Betula lutea Michx. f.

NOMENCLATURE (Sudworth).

Yellow Birch (local and common Swamp Birch (Minn.).

name). Silver Birch (N. H.).

Gray Birch (Vt., R. I., Pa., Mich., Merisier, Merisier Rouge (Quebec).

Minn.).
American Mahogany.

LOCALITIES.

Newfoundland to North Carolina, westward intermittently to Manitoba
and Texas; best developed north of the Great Lakes.

FEATURES OP TREE.

Sixty to eighty or more feet in height; two to four feet in diameter; a
medium-sized tree; the bark on the trunk is silver-gray to silver-yellow,
while the bark on the branches varies between green and lustrous or
dull-brown; the bark exfoliates, causing a rough, ragged appearance.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light reddish brown; sapwood nearly white; close-grained;
compact structure; satin-like appearance.

STRUCTURAL QUALITIES OF WOOD.

Heavy, strong, hard, and tough; is susceptible to a high polish; the quali-
ties suggest those of Maple; is not durable when exposed to the weather.

REPRESENTATIVE USES OF WOOD.

Furniture, buttons, tassel-moulds, pill-boxes, spools, wheel-hubs, and
chair seats; occasional burls are valued for making mallets; the wood is
also used as a base upon which enamelled paints are applied.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

40.
MODULUS OF ELASTICITY.

2,290,000.
MODULUS OF RUPTURE.

17,700.
REMARKS.

The thin outer bark is sometimes ruptured in such a way as to show the
almost metallic yellow of the inner bark. The name is due to the
yellow appearance of the inner bark, which is also characterized by the
fact that it possesses a pungent, pleasant flavor.

164 ORGANIC STRUCTURAL MATERIALS

Sweet Birch, Cherry Birch. Betula lenla Linn.

NOMENCLATURE (Sudworth). Black Birch (N. H., Vt., Mass.,

Sweet Birch, Cherry Birch. R. I., Conn., N. Y., N. J., Pa.,

(many localities). W. Va., Ga., 111., Ind., Mich.,

Mahogany Birch (N. C., S. C.). Ohio).

River Birch (Minn.). Mountain Mahogany (S. C.).

LOCALITIES.

Newfoundland, intermittently to Illinois, southward intermittently along
the Alleghanies to Kentucky, Tennessee, and Florida.

FEATURES OF TREE.

Fifty to eighty feet in height; three to four feet in diameter; the dark red-
dish-brown bark resembles that of the Cherry; it does not separate into
layers as in the case of the Paper Birch (Betula papyrifera) ; the leaves,
bark, and twigs are sweet, spicy, and aromatic.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark brown, tinged with red; sapwood light brown or yellow;
close-grained ; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Heavy, very strong, and hard ; the wood is often stained so as to resemble
cherry and mahogany; it is also used as a base upon which enamelled
paints are applied.

REPRESENTATIVE USES OF WOOD.

Woodenware, furniture, ship-building (Canada), and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

47.
MODULUS OF ELASTICITY.

2,010,000.
MODULUS OF RUPTURE.

17,000.
REMARKS.

A common tree in some of the Northern States. The name Cherry Birch
is due to the bark, the appearance of which suggests that of the Cherry
tree. The name Sweet Birch is due to the sweet, spicy essences in the
bark.

LOCUST, MESQUITE

Robinia, Gleditsia, Prosopis

The name Locust applies to species of three distinct genera of
•the family Leguminosse. The Black Locust (Robinia pseud-
acacia), the Honey Locust (Gleditsia triacanthos) , and the Mesquite
or Honey Locust (Prosopis juli flora) grow in the United States.1

The wood of the Black Locust is noted for toughness, dura-
bility, and great torsional strength. Black Locust trenails and
wheel-spokes have few, if any, superiors. Black Locust trees
may be known by their clusters of large peablossom-shaped
flowers and by their bean-shaped pods, which are from three to
six inches in length. The large thorns on the trunks are also
characteristic. There are several species and varieties of the
genus Robinia in the United States.

The wood of the Honey Locust resembles that of the Black
Locust, but is seldom used, save in rough constructions, as fence
rails. The Honey Locust bears blossoms that are smaller than
those of the Black Locust, but the pods of the Honey Locust are
from ten to eighteen inches long. There are several species and
varieties.

The wood of the Mesquite is hard, heavy, and practically
indestructible when exposed. Mesquite beams exist in some
native houses in the Southwest, and Mesquite railway ties and
fence posts are also occasionally seen. Mesquite trees are found
where those of other species cannot grow. They can survive
when almost entirely covered with sand. To the localities in
which they grow, they are much as Bamboos are to China and
Japan. The woods themselves are valued; the rich, pulpy pods
are used as food ; a mucilage is made from the gum ; and a dye is
made from the sap. One other species, the Screwpod Mesquite
(Prosopis odorata) is found in the United States.

1 See also "An Economic Study of Acacias/' Shinn ("United States Depart-
ment of Agriculture, Bulletin No. 9, 1913). "The Locusts/' Detwiler
(American Forestry, February, 1917).

165

166 ORGANIC STRUCTURAL MATERIALS

Locust, Black Locust, Yellow Locust. Robinia pseudacacia Linn.

NOMENCLATURE (Sudworth). Red Locust, Green Locust (Term.).

Locust, Black Locust, Yellow Honey Locust (Minn.).

Locust (local and common White Locust (R. I., N. Y., Tenn.).

names). Acacia (La.).

False Acacia (S. C., Ala., Tex.,

Minn.
Pea-flower Locust, Post Locust

(Md.).

LOCALITIES.

Mountains, Pennsylvania to Georgia, westward to Iowa and Kansas;
widely naturalized in the northeastern part of the United States.

FEATURES OF TREE.

Fifty to seventy feet in height; two to three feet or over in diameter; the
seven to seventeen leaflets curl up or close at night ; there are long spines
on young branches.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish; the thin sap wood is of a light greenish-yellow color;
close-grained and compact; the annual layers are clearly marked.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; durable when exposed to the weather.

REPRESENTATIVE USES OF WOOD.

Long wooden bolts or pins called trenails ; posts, ties, construction, turnery,
ship-ribs, ornamentation, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

45.
MODULUS OF ELASTICITY.

1,830,000.
MODULUS OF RUPTURE.

18,100.
REMARKS.

Extensively planted, particularly in the West. Subject to attacks by
insect-borers. One of the most valuable timber trees in the United
States. Heartwood forms very early in the life of this tree.

BROADLEAF TRUNKS AND WOODS 167

Honey Locust. Gleditsia triacanthos Linn.

NOMENCLATURE (Sud worth). Honey or Honeyshucks (R. I., N. J.,

Honey Locust (local and common Va., Fla., La.).

name). Honeyshucks Locust (Ky.).

Thorn or Thorny Locust Tree or Sweet Locust (S. C., La., Kan.,

Acacia (N. Y., N. J., Ind., Neb.).

Tenn., La.). Piquant Amourette (La.).

Three-thorned Acacia (Mass., Confederate Pintree (Fla.).

R. I., La., Tex., Neb., Mich.). Locust (Neb.).
Black Locust (Miss., Tex., Ark.,

Kan., Neb.).

LOCALITIES.

Ontario and Pennsylvania to Florida, westward intermittently to Ne-
braska and Texas; best in lower Ohio River basin.

FEATURES OP TREE.

Seventy to ninety feet or more in height; two to four feet in diameter;
long spines are plentiful on some individuals, but are absent on others;
the brown fruit pods, which are from ten to eighteen inches long, contain
sweetish, succulent pulp.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood bright brown or red; sap wood yellowish; annual layers
strongly marked; coarse-grained; the medullary rays are conspicuous.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; very durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.

Fence-posts, rails, wagon-hubs, rough construction work, etc.1

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

42.
MODULUS OF ELASTICITY.

1,540,000.
MODULUS OF RUPTURE.

13,100.
REMARKS.

These trees are widely cultivated for landscape effects. They are also
used in hedges.

1 See also "Honey Locust," Pinchot (United States Forest Service, Cir-
cular No. 74, 1907).

168 ORGANIC STRUCTURAL MATERIALS

Mesquite. Prosopis juliflora de C.

NOMENCLATURE (Sudworth) Honey Pod or Honey Locust (Tex.,

Mesquite (Tex., N. M., Ariz., N. M.).

Cal.). Ironwood (Tex.).

Algaroba (Tex., N. M., Ariz.,

Cal.).

LOCALITIES.

Texas, west to the San Bernardino Mountains in California. Also
Colorado, Utah, Nevada, and northern Mexico. Mesquite trees are
cultivated in Hawaii.

FEATURES OF TREE.

Forty to fifty feet in heigth; one to two feet in diameter; sometimes a low
shrub; the roots are often very large; the pods contain a sweet pulp;
there are gums which resemble gum arabic.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood rich dark brown, often red; sapwood clear yellow; close-
grained; compact structure; distinct medullary rays.

STRUCTURAL QUALITIES OP WOOD.

Weak, difficult to work, heavy, hard, and very durable receives a high
polish.

REPRESENTATIVE USES OF WOOD.

Posts, fencing, ties, house-beams, fuel, and charcoal.

WEIGHT OP SEASONED WOOD IN POUNDS PER CUBIC FOOT.

47.
MODULUS OP ELASTICITY.

820,000.
MODULUS OP RUPTURE.

6,800.
REMARKS.

The Mesquite tree can survive when almost entirely covered with sand.
The roots develop greatly in their search for water, and are often dug up
and used for fuel in localities where there is nothing better. The
tree is important locally.

CHAPTER VII

BANDED TRUNKS AND WOODS (CONTINUED)
BROADLEAF SERIES, PART Two

Dicotyledons

WHITEWOOD OR TULIP-TREE WOOD. POPLAR OR COTTON-
WOOD. CUCUMBER-TREE WOOD. BASSWOOD.

Liriodendron. Populus. Magnolia. Tilia.

These unrelated trees are grouped together because they yield
similar, soft, clean, fine-grained woods that are all valued for
indoor work. The woods all last well when protected from the
weather, but no one of them is durable when exposed.

The Whitewood or Tulip-tree (Liriodendron tulipifera) is a
native of North America. The wood, which is the best of its
kind, is soft, rigid, fine-grained, clean, free from knots, straight-
grained, capable of being nailed without splitting, and obtainable
in large-sized pieces. It is used for boxes, shelves, the bottoms
of drawers, and house-trim. In spite of its name, it is of a
greenish-yellow color. The trees are often very large. Mat-
thews1 mentions a specimen that was thirty-nine feet in circum-
ference. Whitewood trees may be known by their large tulip-
shaped flowers.

Poplar Trees Grow on Both Hemispheres. — The tough, light
woods will indent without breaking, and were formerly used for
shields. The woods are now used much as whitewood is used,
for trunks, boxes, woodenware, and indoor finish, but they are
not as good as whitewood. The trees are sometimes called
Cottonwoods because their seeds are covered with a cotton-like
down. The foliage of some species, as the Aspen (Populus
tremuloides) , is agitated by the slightest wind. This is due to the
shape of the long leaf-stems2.

The Balsam Poplar or Balm of Gilead (Populus balsamifera) ,
which thrives far into the North, must not be confused with the
true Balsam or Balm of Gilead (Abies balsamea). Sudworth
credits twelve species of the genus Populus to the United States.

The Cucumber-tree (Magnolia acuminata) is a member of the
Magnolia family, and yields a wood that is seldom distinguished
commercially from Whitewood.

169

170 ORGANIC STRUCTURAL MATERIALS

Basswood Trees are Known by Many Names. — Limes, Lime-
trees, Lind, Linden, Tiel, Tieltrees, Beetrees, Bass, and Basswood
trees are the same. The woods are prized for their working
qualities which resemble, but are inferior to those of white wood;
and the trees are prized for their dense shade and fine appearance.
The Basswood (Tilia americana) is the principal species in the
United States. Basswood trees bear small, fragrant, cream-
colored flowers that are often surrounded by bees.

"Familiar Trees," F. Schuyler Matthews (p. 39, Appleton, 1901).
2 See also "The Aspens," Weigle and Frothingham (United States Forest
Service, Bulletin No. 93, 1911); "Cottonwood in the Mississippi Valley,"
Williamson (United States Department of Agriculture, Bulletin No. 24,
1913.)

BROADLEAF TRUNKS AND WOODS 171

Tulip Tree, Whitewood, Yellow Poplar. Liriodendron tulipifera Linn.

NOMENCLATURE (Sudworth).

Tulip Tree, Whitewood, Yellow Hickory Poplar (Va., W. Va.,

Poplar (local and common names). N. C.).

Poplar (R. I., Del., N. C., S. C., Fla., Blue Poplar (Del., W. Va.).

Ohio). Popple (R. I.).

Tulip Poplar (Del., Pa., S. C., 111.). Cucumber Tree (N. Y.).

Canoewood (Tenn.).
LOCALITIES.

New England to Florida, westward intermittently to Michigan and
Arkansas.

FEATURES OF TREE.

Ninety to one hundred and fifty feet in height; six to twelve feet in di-
ameter; tulip-shaped flowers appear in the spring; the greenish cone-like
fruit dries and remains after the leaves have fallen.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light yellow or greenish brown; the thin sapwood is nearly
white; close and straight-grained; compact structure; free from knots.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, moderately strong, but brittle; easily worked; not dur-
able in contact with the ground; hard to split; shrinks little; resembles
White Pine (Pinus strobus); stands well in protected places.

REPRESENTATIVE USES OF WOOD.

Lumber, interior finish, woodenware, shelves, and bottoms of drawers;
used as a base upon which enamelled paints are applied.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

26.
MODULUS OF ELASTICITY.

1,300,000.
MODULUS OF RUPTURE.

9,300.
REMARKS.

Very large trees were formerly common. Whitewood is sometimes
divided by lumbermen into "White Poplar" and "Yellow Poplar."
One of the largest and most useful of American deciduous trees.

172 ORGANIC STRUCTURAL MATERIALS

Poplar, Largetooth Aspen. Populus grandidentata Michx.

NOMENCLATURE (Sudworth).

Poplar, Largetooth Aspen (local White Poplar (Mass.).

and common names). Popple (Me.).

Largetooth Poplar (N. C.). Large American Aspen (Ala.).

Large Poplar (Tenn.).

LOCALITIES.

Nova Scotia and. Delaware, westward intermit tentty to Minnesota.
Alleghany. Mountains, to Kentucky, and Tennessee.

FEATURES OP TREE.

Sixty to eighty feet in height; two feet or more in diameter; there are
irregular points or teeth on the margins of the leaves; the flowers
appear before the leaves in the spring; the gray bark is smooth.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish; sapwood nearly white; close-grained; compact
structure.

STRUCTURAL QUALITIES OF WOOD.
Soft, light, and weak.

REPRESENTATIVE USES OF WOOD.

Paper-pulp and occasionally woodenware.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,360,000.
MODULUS OF RUPTURE.

10,200.
REMARKS.

The Quaking Aspen (Populus tremuloides) has long leafstalks, flattened
vertically to the leaf-surfaces, which cause the leaves to tremble in
slight winds. This characteristic is more or less pronounced with other
species of the genus Populus.

Ailanthus (Ailanthus glandulosa). This sturdy, beautiful, very quick-
growing, but short-lived tree was once popular in the United States, par-
ticularly in city landscapes, but it was discarded because of the disagree-
able, far-reaching odor of its flowers. The tree has many merits. In
Europe, the wood is used for woodenware and charcoal; in China, certain
silkworms feed upon the leaves of the trees. The Chinese call the Ailanthus
the "Tree of Heaven." American specimens have grown in excess of ten
feet in length during the first year.

BROADLEAF TRUNKS AND WOODS 173

„ , IPopulus deltoides Marsh

Cottonwood. 1 r> 7 -7 •* A M

(Populus monihfera Ait.

NOMENCLATURE (Sudworth).

Cottonwood (local and common Big Cottonwood (Miss., Neb.).

name). Whitewood (la.).

Carolina Poplar (Pa., Miss., La., Cotton Tree (N. Y.).

N. M., Ind., Ohio). Necklace Poplar (Tex., Colo.).

Yellow Cottonwood (Ark., la., Broadleaved Cottonwood (Colo.).

Neb.).

LOCALITIES.

Canada to Florida, westward intermittently to Rocky Mountains.

FEATURES OF TREE.

Seventy-five to one hundred feet in height; four to five feet in diameter;
occasionally much larger; long catkins distribute cotton-like fibers.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Thin heartwood dark brown; sapwood nearly white; close-grained; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, soft, weak, liable to warp, and difficult to season.

REPRESENTATIVE USES OF WOOD.

Greatly valued in the manufacture of paper-pulp; also used for packing-
boxes, fence-boards, and fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

24.
MODULUS OF ELASTICITY.

1,400,000.
MODULUS OF RUPTURE.

10,900.
REMARKS. —

See also "Cottonwood" (United States Forest Service, Circular No. 77).

174 ORGANIC STRUCTURAL MATERIALS

Black Cottonwood. Populus trichocarpa Ton. and Gr.

NOMENCLATURE (Sud worth). Cottonwood (Oreg., Cal.).

Black Cottonwood (Oreg., Cal.). Balm Cottonwood (Cal.).
Balsam Cottonwood, Balm (Oreg.).

LOCALITIES.

Pacific Coast region, Alaska to California.

FEATURES OF TREE.

A large tree, sometimes one hundred and fifty feet in height and four to six
feet in diameter; the broadly ovate leaves have blunt, marginal teeth.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light dull brown; sapwood nearly white; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, soft, and weak.

REPRESENTATIVE USES OF WOOD.
Staves, and sometimes woodenware.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

23.
MODULUS OF ELASTICITY.

1,580,000.
MODULUS OF RUPTURE.

8,400.
REMARKS.

The largest deciduous tree of the Puget Sound district.

The Cottonwood, Tacmahac, Balsam, Balsampoplar, or Balm of Gilead
(Populus balsamifera) which grows from Hudson Bay and Alaska, southward
to Oregon and New England is a distinctly northern species. The large
upright trunk yields a light, soft, light-colored wood which has been used in
making paper. The exudations are sometimes used in medicine.

BROADLEAF TRUNKS AND WOODS 175

Cucumber-tree. Magnolia acuminata Linn.

NOMENCLATURE (Sudworth). Mountain Magnolia (Miss., Ky.).

Cucumber-tree (R. I., Mass., N. Y., Black Lin, Cucumber (W. Va.).

Pa., N. C., S. C., Ala., Miss., La., Magnolia (Ark.).
Ark., Ky., W. Va., Ohio, Ind., 111.).

LOCALITIES.

New York to Illinois, southward intermittently through Kentucky and
Tennessee to the Gulf.

FEATURES OF TREE.

Fifty to occasionally one hundred feet in height; two to four feet in diame-
ter; a large, handsome, symmetrical tree, with fruit suggesting cucum-
bers; large greenish-yellow or cream-colored flowers.

COLOR, APPEARANCE OR GRAIN OF WOOD.

Heartwood brownish yellow ; sap wood nearly white; close-grained; com-
pact structure; thin medullary rays.

STRUCTURAL QUALITIES OF WOOD.
Light, soft, not strong, but durable.

REPRESENTATIVE USES OF WOOD.

Cabinet-making, cheap furniture, flooring, pump-logs, troughs, crates,
and packing-boxes.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

29.
MODULUS OF ELASTICITY.

1,310,000.
MODULUS OF RUPTURE.

9,500.
REMARKS.

The wood resembles and is often sold for that obtained from the Tulip Tree
(Liriodendron lulipifera).

176 ORGANIC STRUCTURAL MATERIALS

Basswood, Linn, Linden. Tilia americana Linn.

NOMENCLATURE (Sudworth). Whitewood (Vt., W. Va., Ark.,

Basswood, Linn, Linden, Ameri- Minn.).

can Linden (local and common Yellow Basswood, Lein (Ind.).

names). Beetree (Vt., W. Va., Wis.).

Limetree (R. I., N. C., S. C., Ala., White Lind (W. Va.).

Minn., La., 111.). Wickup (Mass.).

Black or Smooth-leaved Lime-
tree (Tenn.).

LOCALITIES.

New Brunswick to Georgia, westward intermittently to Manitoba and
Texas. A wide range.

FEATURES OP TREE.

Sixty to ninety feet in height; two to four feet in diameter; occasionally
larger; large smooth leaves; fragrant flowers, borne on slender, leaf -like
structures.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light or reddish brown ; thick sap wood nearly similar; very
straight and close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, easily worked, and tough; not strong or durable.

REPRESENTATIVE USES OF WOOD.

Sides and backs of drawers, bodies of carriages, woodenware, and paper-
pulp.1

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

1,190,000.
MODULUS OF RUPTURE.

8,300.
REMARKS.

Parts of the inner bark have occasionally been utilized for cordage. The
fragrant flowers attract bees. The wood of the White Basswood (Tilia
heterophylld] is not distinguished from that of the Common Basswood
by dealers.

!See also "Basswood," Pinchot (United States Forest Service, Circular
No. 63, 1907).

BROADLEAF TRUNKS AND WOODS 177

WILLOW

Salix

The willows grow in many places on both hemispheres.
North Americans value the fast-growing, characteristically
shaped trees; while Europeans value the woods. The principal
experience with the wood of the Willow has been gained in
Europe. The wood is light, tough, easily worked, and elastic.
It resists splintering, stands well against abrasion, and in Europe
is used for friction-brake linings, lapboards, cricket bats, keels
and paddles, Willow charcoal ignites readily and for this reason
is used in gunpowder. Willow rods are used in basket-making.1

In the United States Willow trees are used to protect and some-
times, by creating eddies, to recover land from water encroach-
ment. Saplings up to three or four inches in diameter are used
in river improvements. These saplings are made into mattresses
which are placed along the banks of streams to prevent scour.
Some of the mattresses thus constructed for Mississippi River
improvement work are three hundred feet wide and one thousand
feet long.2 Saplings are known as " Osiers" and are regularly
cultivated in Europe.

The term Osier Willow is sometimes applied to trees that yield
strong, slender shoots. The true Osier, Sandbar, or Longleaf
Willow (Salix fluviatilis) grows in many places from the Arctic
Ocean southward to Mexico. The White, Crack, Bedford, and
Goat Willows (Salix alba, Salix fragilis, Salix russeliana, and
Salix caprea) are said to afford good woods.

1 See also "The Basket Willow" (United States Forest Service, Bulletin
No. 46); "Production and Consumption of Basket Willows in the United
States, etc.," Mell (United States Forest Service, Circular No. 155, 1909);
"Basket Willow Culture," Lamb (United States Department of Agriculture,
Farmers" Bulletin No. 622, 1914); "Willows: Their Growth, Use, and Im-
portance," Lamb (United States Forest Service, Bulletin No. 316, 1915).
"The Willows: Identification and Characteristics," Detwiler, (American
Forestry, January, 1917).

2 "Bank Revetment on the Lower Mississippi," Coppee (Transactions
American Society of Civil Engineers, Vol. 35, p. 198); "Erosion of River
Banks on the Mississippi and Missouri Rivers," Ockerson (Transactions
American Society of Civil Engineers, Vol. 38, p. 396).

178 ORGANIC STRUCTURAL MATERIALS

Black Willow. Salix nigra Marsh

NOMENCLATURE (Sudworth). Willow (N. Y., Pa., N. C., S. C.,

Black Willow (local and common Miss., Tex., Cal., Ky., Mo.,

name). Neb.).
Swamp Willow (N. C., S. C.).

LOCALITIES.

New Brunswick to Florida, westward intermittently to the Dakotas,
Arizona, California, and Mexico ; grows best on bottom lands and along
the borders of rivers.

FEATURES OP TREE.

Forty to fifty feet in height; two to four feet in diameter; long, narrow
leaves; a characteristic appearance.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood brown ; sap wood nearly white ; close-grained.

STRUCTURAL QUALITIES OF WOOD.

Soft, light, and weak; checks badly in drying; readily worked; dents with-
out splitting.

REPRESENTATIVE USES OF WOOD.
Lap-boards, basket-making, fuel, and charcoal.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

27.
MODULUS OF ELASTICITY.

550,000.
MODULUS OF RUPTURE.

6,000.
REMARKS.

Many species and varieties of Willow trees grow in the United States, but
none of them yield wood that is used to any extent in construction.
Willow rods, either whole or split, are used by basket makers. It is
said that sap-peeled rods retain their light color, and that steamed rods
turn yellow. The European uses of Willow wood have been referred to.

The White Willow (Salix alba}, which has been naturalized in North Amer-
ica, is hardy, even when located in dry places. On the prairies, this tree is
sometimes used as a wind-break. Trees planted several feet apart serve as
fence-posts to support barbed wire.

BROADLEAF TRUNKS AND WOODS 179

CATALPA

Catalpa

Catalpa trees grow in the eastern part of the United States, in
the West Indies, and in some parts of China. The Common
Catalpa (Catalpa catalpa) and the Hardy Catalpa (Catalpa
speciosa) are natives of North America. The name of the genus
is that which was given to one of these species by the Cherokee
Indians.

Until recently the Catalpas have attracted but little attention.
But they are now regarded with interest, because, when the right
conditions prevail, the trees grow rapidly and yield woods that
can be used in construction. Catalpa trees have reached a
thickness of as much as sixteen inches in seventeen years. The
wood is soft, weak, brittle, clean, smooth-grained, and very
durable. Von Schrenk believes that the final disintegration of
this wood will not be due to attacks from fungi, since no fungus
has yet been found that will grow in dead Catalpa lumber. The
wood is attractive in appearance and is suitable for some forms of
interior finish as well as for carpentry. Catalpa posts and poles
are highly valued, but railway ties of this wood do not stand well
under heavy traffic. The supply of Catalpa wood thus far is
limited.

Catalpa trees may be known by their flowers and by their long
beans, which are sometimes known as smoking-beans.1

1 The Forester, October, 1900, and November, 1902. Forestry Quarterly,
vol. iii, N. Y. "An Experiment in Western Catalpa." (Report of the Penn-
sylvania Dept. of Forestry for 1910-11.) "Hardy Catalpa," Hall and von
Schrenk (United States Forestry Bureau, Bulletin No. 37).

180 ORGANIC STRUCTURAL MATERIALS

Catalpa, Hardy Catalpa. Catalpa speciosa Warder

NOMENCLATURE (Sudworth).

Catalpa (R. I., N. Y., La., 111., Western Catalpa (Pa., Ohio, la.,

Ind., Mo., Wis., la., Neb., Neb., 111.).

Minn.). Cigar Tree (Mo., la.).

Hardy Catalpa (111., la., Kan., Indian Bean, Shawneewood (Ind.).

Mich.). Bois Puant (La.).

LOCALITIES.

Central Mississippi Valley, naturalized in many localities.

FEATURES OP TREE.

Forty to sixty feet or more in height; three to six feet in diameter; well-
formed trunk; large, white, faintly mottled flowers; long pods or beans.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heartwood brown; thin sapwood lighter, nearly white; coarse-
grained; compact structure; annual layers clearly marked ; an attract-
ive wood.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, not strong, but durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.

Railway ties, fence-posts, and rails; can be used in cabinet-work and
interior finish.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

25.
MODULUS OF ELASTICITY.

1,160,000.
MODULUS OF RUPTURE.

9,000.
REMARKS.

Catalpa trees are not seriously injured by occasional inundations, and, for
this reason, are sometimes planted along streams. Under the right
conditions, they grow rapidly, and are sometimes used in landscape
effects. As a rule, the trunks of the Hardy Catalpa are better formed
than those of the Catalpa.

Paulownia (Paulownia tomentosa). This tree is a native of Asia, but is
now cultivated in some of the Central-Atlantic and Southern States. It
has catalpa-like leaves, which are preceded by large pale blue or violet
flowers and followed by woody, capsule-like fruit that in form suggests
hickory nuts. The species, which is of small importance, is not related to
the Catalpa, but is sometimes confused with it.

BROADLEAF TRUNKS AND WOODS 181

P , . | Catalpa catalpa (Linn.) Karst

\ Catalpa bignonioides Walt.

NOMENCLATURE (Sudworth).

Catalpa (local and common name). Indian Bean (Mass., R. I., N. Y.,

Indian Cigar Tree (Pa.). N. J., Pa., N. C., 111.).

Smoking Bean (R. I.). Catawba, Catawba Tree (Del.,

Cigar Tree (R. I., N. J., Pa., W. Va. W. Va., Ala., Fla., Kan.).

Mo., 111., Wis., la.). Beantree (N. J., Del., Pa., Va.,

La., Neb.).

LOCALITIES.

Native only in the Gulf States, but naturalized in many localities east of
the Rocky Mountains.

FEATURES OF TREE.

Thirty to fifty feet in height; one to two or more feet in diameter; often
the trunks are not well formed; low, wide trees, with large heart-
shaped leaves and characteristic flowers; long slender pods or beans;
distinguished from the Hardy Catalpa by the fact that the flowers are
smaller and in denser clusters.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heartwood is light pink brown; the thin sapwood is nearly white;
coarse-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.
Light, soft, not strong, but durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.
Fence-posts, railway ties, etc.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

27.
MODULUS OF ELASTICITY.

960,000.
MODULUS OF RUPTURE.

8,300.
REMARKS.

These trees grow rapidly, but the wood is less desirable than that obtained
from the Hardy Catalpa (Catalpa speciosa). The long pods which
remain on the trees after the leaves have disappeared, are sometimes
used locally as cigars.

182 ORGANIC STRUCTURAL MATERIALS

MULBERRY

Morus

Two species of Mulberry grow in North America, and a few
others grow abroad. Of these, the most valuable is the White
Mulberry (Morus alba), a native of northern China and Japan,
which is now also cultivated in many other countries for its
leaves which form the best food for silkworms. The Red Mul-
berry (Morus rubra) and the Mexican Mulberry (Morus celtidi-
folia) are the species that are native to the United States.

The American species yield fairly hard, rather heavy, and
quite durable woods that are sometimes used in cooperage,
flumes, boats, and fences.

White, Red, and Black Mulberry trees may be distinguished
from one another by the color of their sweet berries.

Red Mulberry, Mulberry. Morus rubra Linn.

NOMENCLATURE (Sudworth).

Red Mulberry, Mulberry (local Virginia Mulberry Tree (Term.).

and common names). Murier Sauvage (La.).

Black Mulberry (N. J., Pa., W.Va.).

LOCALITIES.

Massachusetts to Florida, westward intermittently to Nebraska and
Texas; best in lower Ohio and Mississippi River basins.

FEATURES OF TREE.

Fifty to sixty feet in height; two and one-half to three feet in diameter;
sweet, edible fruit; the leaves are very variable, sometimes entire, but
often three-lobed; dark brown broken bark; smooth gray branches.-

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heartwood, light orange yellow; thin sapwood whitish; coarse-
grained; compact structure; the annual layers are clearly marked.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, not strong, but very durable in contact with the soil; it re-
ceives a good polish.

REPRESENTATIVE USES OF WOOD.
Fencing, cooperage, etc.

WEIGHT OF SEASONED WOODS IN POUNDS PER CUBIC FOOT.

36.
MODULUS OF ELASTICITY. MODULUS OF RUPTURE.

11,700,000. 11,000.

REMARKS.

An ornamental tree.

BROADLEAF TRUNKS AND WOODS 183

HORSE CHESTNUT. BUCKEYE

Aesculus

Horse Chestnut trees (Aesculus hippocastanum) , supposed to
be natives of Asia, have long been among the most popular shade
trees of Europe and North America. The Buckeyes (Aesculus
glabra, Aesculus octandra, and Aesculus californica) grow from
Ohio and southern Iowa, southward to northern Georgia and
northern Louisiana, and in California. The name " Horse Chest-
nut" is probably due to an ironical reference to the coarse nuts,
while the name " Buckeye" refers to the appearance of the nut
of that tree which, under certain conditions, suggests the eye of
the deer.

Horse Chestnut and Buckeye woods resemble one another, in
that both are soft, straight-grained, and easily worked. They
decay rapidly when exposed to the weather. The woods are
sometimes employed in artificial limbs, splints, woodenware, and
paper pulp.

Both trees may be known by their nuts, which are enclosed in
prickly husks.1

also "Trees of Northern States and Canada," Hough, page 338.

184 ORGANIC STRUCTURAL MATERIALS

Ohio Buckeye, Fetid Buckeye. Aesculus glabra Willd.

NOMENCLATURE (Sudworth).

Buckeye, Ohio Buckeye (local Stinking Buckeye (Ala., Ark.).

and common names). American Horse Chestnut (Pa.).

Fetid Buckeye (W. Va.).

LOCALITIES.

Ohio River basin to Alabama, portions of Iowa, Kansas, and Oklahoma.

FEATURES OP TREE.

Twenty-five to forty-five feet in height; one to one and one-half feet in
diameter; the yellowish-white flowers are succeeded by round prickly
pods which contain nuts.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heart wood white; sap wood a little darker; close-grained; frequent dark
lines of decay.

STRUCTURAL QUALITIES OF WOOD.

Weak, light, and soft, but hard to split.

REPRESENTATIVE USES OP WOOD.

Artificial limbs, wooden ware, and paper-pulp; rarely lumber.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28.
MODULUS OF ELASTICITY.

910,000.
MODULUS OF RUPTURE.

7,000.
REMARKS.

The nearly similar Horse Chestnut (Aesculus hippocastanum) is not native,
but is largely planted in North America. It is from forty to fifty or
more feet in height, and is from two to sometimes four feet in di-
ameter. The Horse Chestnut tree is one of the most popular of all
shade trees. The light, weak wood is seldom used.

BROADLEAF TRUNKS AND WOODS 185

f Aesculus octandra Marsh
Buckeye, Sweet Buckeye. 7/7 * •.

{ Aesculus flava Ait.

NOMENCLATURE (Sudworth).

Buckeye (N. C., S. C., Ala., Miss., Yellow Buckeye (S. C., Ala.).

La., Tex., Ky.). Large Buckeye, Big Buckeye (Tex.

Sweet Buckeye (W. Va., Miss., Tenn.).

Tex., Mo., Ind.).

LOCALITIES.

Alleghany Mountains, Pennsylvania to Georgia, westward intermittently
to Iowa and Texas.

FEATURES OF TREE.

Forty to seventy feet in height; one to three feet in diameter; sometimes
a low shrub ; the pods are distinguished from those of the Ohio Buckeye
(Aesculus glabra) by the fact that they are smooth.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood creamy white; sapwood similar; compact structure; close-
grained; difficult to split.

REPRESENTATIVE USES OF WOOD.

Similar to those of the Ohio Buckeye (Aesculus glabra).

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

26.64.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

REMARKS.

The California Buckeye or California Horse Chestnut (Aesculus calif or-
nica), grows along the Pacific Coast from Mount Shasta, southward
to Los Angeles. It is often quite small, but in some localities is from
thirty to forty feet in height. The soft, light, compact, close-grained,
ivory-white wood could probably be employed in turnery.

186 ORGANIC STRUCTURAL MATERIALS

GUM

Liquidambar, Nyssa

This name applies to a number of trees that lie within at least
two genera. One genus (Liquidambar) contributes about four
species, which grow in many places in the eastern part of the
United States and parts of Mexico, Central America, and Asia;
while the other genus (Nyssd) includes five species which grow
only in the eastern part of the United States and in the southern
part of Asia.1

The wood of the Red or Sweet Gum (Liquidambar styraciflua)
is about as strong and stiff as that of the chestnut. It is brittle,
straight-grained, rather fine and dense, absorbent, liable to warp
and twist in seasoning, fairly heavy, and moderately soft. Its
natural color is attractive, but this is often changed by staining,
so as to resemble the colors of other woods. Some pieces of Red
Gum resemble walnut and these are usually cut into veneers
which are sometimes misleadingly sold under such names as
" California Red Gum," "Hazel," " Satin Walnut," and even
" Circassian Walnut." Ordinary pieces are sparingly used for
many purposes, as railway ties, carpentry, flooring, furniture,
paving blocks, packing boxes, barrel staves, pulley-facing, coffin
boards, and woodenware. The trees, which are very attractive
and which are prized in landscape effects, bear rough fruiting
heads or balls about as large as the fruiting heads of the syca-
more. Their pointed, star-shaped leaves exhibit bright scarlet
and purple tints during the autumn.

The wood of the Water Gum or Tupelo Gum (Nyssa aquatica)
is often marketed with that of the Red Gum. This wood is
light, strong, tough, fine-grained, easily glued, and comparatively
cheap. Its cellular arrangement is complicated and the wood is
correspondingly hard to split and work. The heartwood varies
in color from dull gray to dull brown, while the color of the sap-
wood resembles that of ordinary poplar. After seasoning, it is
often hard to distinguish between the sapwood of the better
grades of Tupelo Gum and ordinary poplar. This wood is also
sold under other names, as "Bay Poplar," and "Circassian Wal-
nut," and is used for packing boxes, furniture, the backs of
drawers, and house-trim. The trees, which often grow in deep
swamps and along the margins of water courses, bear leaves

BROADLEAF TRUNKS AND WOODS 187

which exhibit beautiful purple and reddish tints in the autumn.
The Sour Gum or Black Gum (Nyssa sylvatica) yields a rather
soft, light, tough, fine, but irregularly grained wood, which is
hard to split and work, and which is used for wheel-hubs, rollers,
woodenware, thin lumber, and fruit crates. The Sour Gum tree
grows in swamps and hardwood bottoms. Its range is greater
than that of the others, but the Sour Gum forms a much less
important part of the forest.

1 See also "The Red Gum" Chittenden and Hatt (United States Forest
Service, Bulletin No. 58, 1906), "The Utilization of Tupelo," Holroyd
(United States Forest Service, Circular No. 40, 1906), "Distinguishing
Characteristics of North American Gumwoods," Sudworth and Mell (United
States Forest Service, Bulletin No. 103, 1911), ''The Red Gum" Detwiler
(American Forestry, November, 1916).

188 ORGANIC STRUCTURAL MATERIALS

Gum, Sweet Gum, Red Gum. Liquidambar styraciflua Linn.

NOMENCLATURE (Sudworth).

Gum, Sweet Gum, Red Gum Gum Tree (Va., S. C., La.).

(local and common names). Alligatorwood, Blisted, (N. J.).

Liquidambar (R. I., N. Y., Del.,
N. J., Pa., La., Tex., Ohio, 111.).

LOCALITIES.

Connecticut to Florida, westward intermittently to Illinois, Texas, and
. . Mexico; best development in basin of Mississippi River.

FEATURES OF TREE.

Eighty to one hundred or more feet in height; three to five feet in diameter;
a tall, straight trunk; corky ridges are frequent on the branches; the
star-shaped leaves turn to brilliant scarlet in the autumn; there are
round balls on long stems.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood rich brown, suggests Black Walnut; sapwood nearly white;
close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

About as strong and stiff as Chestnut ;l heartwood is durable when exposed ;
wood shrinks and warps badly if seasoned by ordinary methods, but
responds to special methods; glues and paints well; holds spikes well;
receives a high polish; tasteless.

REPRESENTATIVE USES OF WOOD.

Veneers, cabinet-work, packing boxes, carpentry, shingles, clapboards,
paving-blocks, wooden plates, and barrel staves.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
37 (United States Forestry Division).
36.

MODULUS OF ELASTICITY.

1,700,000 (average of 118 tests by United States Forestry Division).2
1,220,000.

MODULUS OF RUPTURE.

9,500 (average of 118 tests by United States Forestry Division).2
9,200.

REMARKS.

The wood has other commercial names as "Hazel," "Satin Walnut,"
"Star-leaved Gum." Clear wood can be obtained in boards of large
size. The larger trees often have hollow butts.

1 Woodward, reported Gum ties as good after five years of service on the
Texas & Pacific Railroad.

2 See p. 33.

BROADLEAF TRUNKS AND WOODS 189

Tupelo Gum, Cotton Gum, Large Tupelo. Nyssa aquatica Linn.

NOMENCLATURE (Sudworth).

Tupelo Gum, Cotton Gum, Large Tupelo, Swamp Tupelo (N. C.

Tupelo (local and common S. C., La.).

names). Olivetree, Wild Olivetree (Miss.

Sour Gum (Ark., Mo.). La.).

LOCALITIES.

Virginia and Kentucky, southward and westward to Missouri and Texas.

FEATURES OF TREE.

Sixty to eighty feet in height; two to three feet in diameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown, often nearly white; sapwood nearhr the same.

STRUCTURAL QUALITIES OF WOOD.

Soft, light, not strong; close, compact grain; difficult to work.

REPRESENTATIVE USES OF WOOD.

Turnery, woodenware, boxes, and fruit-crates; pieces of the root are some-
times used to float nets.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

32.
MODULUS OF ELASTICITY.

730,000.
MODULUS OF RUPTURE.

9,300.
REMARKS.

These trees grow on rich bottom lands and in deep swamps. They are
often associated with cypress trees. The specific name is due to the
fact that the trees tolerate quantities of water. The butts of large
trees are usually hollow, while the parts above are usually sound.

The Sour Gum (Nyssa ogeche) grows along the Atlantic Coast from South
Carolina to Northern and Western Florida. The trees, which are usually
found on wet lands, attain heights of from thirty to fifty feet. The soft,
compact, weak, brownish heartwood is hardly distinguishable from the
brownish sapwood. The tree is also known as.Ogeechee Lime, Wild Lime-
tree, Limetree, Tupelo, Sour Tupelo, and Gopher Plum.

190 ORGANIC STRUCTURAL MATERIALS

Sour Gum, Black Gum, Tupelo. ( "yssa sylv^a "

{ Nyssa multiflora Wang.

NOMENCLATURE (Sud worth).

Sour Gum, Black Gum, Tupelo Wild Pear Tree, Yellow Gum Tree

(local and common names). (Tenn.).

Pepperidge (Vt., Mass., R. I., Gum (Md.).

N. Y., N. J., S. C., Tenn., Mich., Stinkwood (W. Va.).

Ohio, Ontario). Tupelo Gum (Fla.).

LOCALITIES.

Ontario and Maine to Florida, westward intermittently to Michigan and
Texas.

FEATURES OF TREE.

Forty-five to one hundred feet in height; several inches to occasionally
four feet in diameter; ovoid, bluish black, sour fruit, with ribbed seed;
horizontal branches; short, spur-like lateral branchlets.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light brown or yellow, often nearly white; the sapwood is
hardly distinguishable; fine-grained; interwoyen cell-structures.

STRUCTURAL QUALITIES OF WOOD.

Strong, tough, not hard; the cell-structures are interlaced, and for this
reason the wood checks unless it is carefully seasoned; it is hard to
work.

REPRESENTATIVE USES OF WOOD.

Wagon-hubs, rollers, and ox-yokes; wooden ware, such as bowls and shoes;
thin lumber is used for boxes and crates; selected pieces used in cabinet
work.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

39.
MODULUS OF ELASTICITY.

1,160,000.
MODULUS OF RUPTURE.

11,800.
REMARKS.

These trees grow on hillsides and along the borders of swamps and water-
ways. Large trees are often hollow near the ground. The wood has a
limited field of usefulness because it is so hard to work.

BROADLEAF TRUNKS AND WOODS 191

HOLLY BOXWOOD LIGNUMVIT^

Ilex Buxus, Cornus, etc. . Guajacum

These trees yield small but very perfect pieces of wood that
fill needs for which no other woods seem equally fitted.

Holly trees (Ilex opaca) grow along the coast in the United
States from Quincy, Massachusetts, to Louisiana, and in the
interior, in parts of Missouri, Illinois, Kentucky, Tennessee, and
Arkansas. The wood, which is noted for its fine even grain and
its smooth, ivory-white color, is used for carvings, decorations,
and inlaid work, where fine qualities and white effects are re-
quired. The European source is the Holly (Ilex aquifolium).
Holly trees are noted for their brilliant evergreen foliage and
bright red berries, that have long been associated with the Christ-
mas season.

The true Boxwood (Buxus sempervirens) becomes a tree in
some parts of Europe, Asia, and northern Africa, but, in the
United States, is generally a small shrub that is useless, save in
landscape effects. The wood is noted for its fine, firm, even
texture and is used for carvings and mathematical instruments.
No other wood is better for wood engravings. Boxwood is often
hard to season. It is said that French engravers place pieces
designed for their finest work in dark cellars as soon as they are
cut, and that they keep them in such surroundings for several
years before they are used. American Boxwood is derived from
the Flowering Dogwood (Cornus florida) and from several other
species.

The Lignum vitaes (Guajacum sanctum and Guajacum officinale)
grow in Florida, the West Indies, Colombia, and Venezuela, and
yield wood that is noted for great weight, strength, complicated
cellular structure, and durability. Under the axe, it may be said
to crumble rather than to split. It contains a resin (Guajac) that
is sometimes used in medicine and as a lubricant. The wood is
used for rollers, pulley sheaves, tool handles, and sometimes in
place of bearing metals in parts of marine engines. Some
lignum vitse ties, removed from the Panama Railway after more
than thirty years of service, because they were too small to
afford proper bearings for the rails, were still in good condition.

192 ORGANIC STRUCTURAL MATERIALS

Holly, American Holly. Ilex opaca Ait.

NOMENCLATURE (Sudworth).

Holly, American Holly (local White Holly (Va.).
and common names).

LOCALITIES.

Maine to Florida, westward intermittently to Indiana and Texas.

FEATURES OF TREE.

Occasionally fifty feet in height and three feet in diameter, but frequently
much, smaller, particularly in the North ; the spiny-margined evergreen
, leaves are of a bright green color; the bright red berries remain until the
spring.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood cream white, darkening or spotting on exposure; sapwood
similar or lighter; very close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Tough, moderately hard and heavy, easily worked.

REPRESENTATIVE USES OF WOOD.

Inlaid work, carvings, scrollwork, and turnery; moderately used for furni-
ture and decoration.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

36.
MODULUS OF ELASTICITY.

910,000.
MODULUS OF RUPTURE.

9,700.
REMARKS.

The wood suggests ivory, and is characteristically employed for the
white of inlaid work. The more elaborate specimens of inlaid work are
manufactured in Italy, but are not always durable when brought into
highly heated houses in the United States. Inlaid work manufactured
in the United States may be less elaborate than the foreign product,
but it is often more durable.

BROADLEAF TRUNKS AND WOODS 193

( Cornus florida Linn.
Dogwood, Flowering Dogwood. | Cynoxylon

NOMENCLATURE (Sudworth). False Box-dogwood (Ky.).

Dogwood, Flowering Dogwood New England Boxwood (Tenn.).

(local and common names). Cornel, Flowering Cornel (Tex.,
Boxwood (Conn., R. I., N. Y., R. I.).

Mich., Ky., Ind., Ont.).

LOCALITIES.

Ontario and New England to Florida, westward intermittently to Minne-
sota and Texas; also found in the Sierra Madre Mountains and in
Mexico.

FEATURES OF TREE.

Twenty-five to thirty-five feet in height; one foot or more in diameter;
often a low shrub; large, white flower-like bracts precede the develop-
ment of the true, but less conspicuous, greenish flowers which precede
the leaves; in the fall, red berries are exhibited; the bark is rough and
dark.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood rich brown, changing to green and red; sap wood lighter;
close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Heavy, strong, tough, and hard; it receives a high polish.

REPRESENTATIVE USES OF WOOD.

Wood-carving, wood-engraving, bearings of machinery, and turnery.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

50.
MODULUS OF ELASTICITY.

1,160,000.
MODULUS OF RUPTURE.

12,800.
REMARKS.

The Mexican or Black Persimmon, and the Great Laurel (Rhododendron
maximum) yield woods that are used in place of Dogwood. The Yellow-
wood (Schcefferia frutescens}, which is found in Florida, also yields
wood that is known as Boxwood. The names Dogwood and Poison
Dogwood are sometimes applied to the Sumach.

194 ORGANIC STRUCTURAL MATERIALS

Lignumvitae. Guajacum sanctum

NOMENCLATURE (Sudworth).
Lignumvitae (Fla.). Ironwood (Fla.).

LOCALITIES.

Semitropical Florida, the Bahamas, San Domingo, Cuba, Puerto Rico,
Jamaica and Yucatan.

FEATURES OF TREE.

Twenty-five feet in height; one foot in diameter; a low, gnarled tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD..

Heartwood rich yellow brown in younger specimens and almost black in
older ones; sapwood light yellow; close-grained; compact structure.

STRUCTURAL QUALITIES OF WOOD.

Very heavy and exceedingly hard; strong, hard to work, and brittle; very
durable; the wood contains a resin which acts as a lubricant when in
water.

REPRESENTATIVE USES OF WOOD.

Rollers, pulley-sheaves, and tool-handles; bearings for parts under water.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

71.
MODULUS OF ELASTICITY.

1,220,000.
MODULUS OF RUPTURE.

11,100.
REMARKS.

Two other species (Guajacum officinale and Guajacum arboreum) afford
similar woods which are not distinguished commercially from the above.

BROADLEAF TRUNKS AND WOODS 195

LAUREL

Magnolia, Rhododendron, Arbutus, etc.

The name Laurel applies locally or botanically to a number of
American plants, several of which attain to the dignity of trees.

The Big Laurel or Magnolia (Magnolia fcetida) grows naturally
along the Atlantic Coast from North Carolina to Florida, and
thence through the Gulf region westward to Texas. The tree,
which is also cultivated in other localities with temperate
climates, is very beautiful and valued in landscape effects, while
the hard, heavy, whitish wood is occasionally used in cabinet
work. The California Laurel (Umbellularia calif ornica) and the
Laurel or Madrona (Arbutus menziesii) are Pacific Coast species,
which yield strong, hard, heavy, and attractive woods that are
sometimes used in furniture. Sargent1 regards the wood of the
former species as the most valuable of those produced in the
forests of the Pacific region for interior finish and furniture. The
wood of the Great Laurel or Rose Bay (Rhododendron maximum)
is hard, rather brittle, close-grained, and heavy, and is sometimes
used as a substitute for Boxwood in wood engraving. The
gnarled roots of the Mountain Laurel or Calico Bush (Kalmia
latifolia) are occasionally used for rustic hanging-baskets, rustic
seats, and the like.

ltl Manual of the Trees of North America," Sargent (Houghton, Mifflin
& Company, 1905, p. 335).

196 ORGANIC STRUCTURAL MATERIALS

California Laurel, Mountain Laurel. Umbellularia calif ornica Nutt

NOMENCLATURE (Sudworth).

California Laurel, Mountain Myrtle-tree, Cajeput, California

Laurel (Cal., Nev.). Olive (Oreg.).

California Bay-tree, Spice-tree Californian Sassafras.

(Cal., Nev., Oreg.).
Laurel, Bay-tree, Oreodaphne

(Cal.).

LOCALITIES.

California and Oregon.

FEATURES OF TREE.

Seventy-five to one hundred feet in height; three to five feet in diameter;
evergreen foliage; beautiful appearance.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood light rich brown; sapwood lighter brown; close-grained; com-
pact structure.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; receives a beautiful polish.

REPRESENTATIVE USES OF WOOD.

Ship-building, cabinet-work, cleats, and crosstrees.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

40.
MODULUS OF ELASTICITY.

1,510,000.
MODULUS OF RUPTURE.

11,400.
REMARKS.

A valuable local cabinet wood.

BROADLEAF TRUNKS AND WOODS 197

Madron a, Madrona Laurel. Arbutus menziesii Pursh.

NOMENCLATURE (Sudworth).

Madrofia, Madrona Laurel (Cal., Madrone-tree, Manzanita (Oreg.,

Oreg.). Cal.).

Laurel, Laurelwood, Madrone. Madrove (Cal.).

LOCALITIES.

Pacific Coast from British Columbia to southern California.

FEATURES OF TREE.

Fifty to seventy-five feet in height, occasionally higher; two to four feet in
diameter; a straight, well-formed trunk; evergreen foliage; a shrub in the
South.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heartwood reddish; thin sapwood slightly pink; close-grained;
numerous and conspicuous medullary rays.

STRUCTURAL QUALITIES OF WOOD.

Heavy, hard, and strong; checks badly in seasoning.

REPRESENTATIVE USES OF WOOD.

The charcoal is used in gunpowder; the wood is sometimes used for
furniture.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

43.
MODULUS OF ELASTICITY.

1,190,000.
MODULUS OF RUPTURE.

12,000.
REMARKS.

A beautiful ornamental tree yielding attractive wood which is seldom used
save locally. The Madrona tree has been confused with the Laurel,
Madrona, or Mexican Madrona (Arbutus xalapensis or Arbutus texana),
also called the Manzanita, and with the California species of the genus
Arctostaphylos from which Manzanita wood is derived.

The name Manzanita is somewhat loosely used to designate hard, heavy,
close-grained, rich, reddish-brown woods, that in California are sometimes
used for trinkets, such as cuff buttons, checkers, and rulers. Large-sized
pieces of Manzanita wood are rare, and long pieces are practically un-
known. Probably most of this wood is derived from the Manzanitas (Arc-
tostaphylos pungens, Arctostaphylos tomentosa, and Arctostaphylos glauca).

198 ORGANIC STRUCTURAL MATERIALS

SASSAFRAS CAMPHOR TREE

Sassafras Cinnamomum

The Sassafras grows in many parts of the eastern half of the
United States. It was one of the first of the North American
trees to be described in Europe, where at that early date, many
fictitious properties were credited to the aromatic essences by
which it is characterized. The soft, light, brittle, slightly aro-
matic, and rather durable wood is occasionally used for buckets
and fences. The trees may be known by their fragrant, mucilagi-
nous leaves, some of which are without lobes, while others have
lobes on one side, and still others have lobes on both sides. The
characteristic sassafras odor and flavor are more or less evident
in the wood, twigs, and leaves, but are much more pronounced
in the bark of the roots.

The Camphor tree (Cinnamomum camphora) , which is related
to the Sassafras, has been acclimated in California, and, on the
Atlantic Coast, from Charleston to Florida. The trees, with
their shining, evergreen leaves, are very attractive, and, in the
United States, are valued in landscape work. The close-grained,
aromatic, yellowish woods are sparingly used in cabinet work and
insect-proof chests. In Asia, where this tree is native, it is the
chief source of commercial camphor; but, in this country, the
trees, although thrifty, do not appear to secrete the same quanti-
ties of this resin. Camphor is found also in the roots of the
Cinnamon tree (Cinnamomum zeylam'cum) of India and Ceylon.
The Cassia Bark (Cinnamomum cassia), of Burmah and China,
yields cassia but no camphor. Transplanted specimens of the
two last-named trees have been made to grow in some parts of
California and Florida.1

1 See also Dewey (United States Division of Botany, Circular No. 12,
Revised).

BROADLEAF TRUNKS AND WOODS 199

J Sassafras officinale Nees and Eberm.
Sassafras. ^ Sassafras sassafras (Linn.) Karst.

NOMENCLATURE (Sudworth).

Sassafras (local and common Sassafac, Sassafrac (W. Va., Del.).

name). Gumbo file (La., negro).

Saxifrax, Sasifrax Tree (Fla.,

Tenn.).

LOCALITIES.

Vermont to Florida, westward intermittently to Michigan and Texas.

FEATURES OF TREE.

Thirty to fifty feet in height; one to three feet in diameter, sometimes
larger; often a low shrub; characteristic odor; the greenish-yellow flowers
precede the leaves in early spring.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Thick heartwood delicate brown; thin sapwood yellowish-white; coarse-
grained; the annual rings are clearly marked.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, not strong, and brittle; checks in drying; very durable in con-
tact with the soil; the wood is slightly aromatic.

REPRESENTATIVE USES OF WOOD.

Pails, buckets, ox-yokes, fence-posts, and rails.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

31.
MODULUS OF ELASTICITY.

730,000.
MODULUS OF RUPTURE.

8,500.
REMARKS.

The leaves and young shoots are mucilaginous. The bark, leaves, and
wood emit a characteristic odor. The bark of the root is particularly
aromatic. Small Sassafras bushes often form thickets.

200 ORGANIC STRUCTURAL MATERIALS

GREENHEART

Nectandra

The Greenheart tree (Nectandra rodioei), which is a member of
the Laurel family, grows in British Guiana and some adjacent
parts of South America, as well as in the West Indies.

The wood is hard, strong, tough, and very heavy. The
colors of the heartwood vary from dark green to chestnut brown,
selected pieces presenting an exceptionally rich appearance when
finished. The quality of durability, which is partly due to the
presence of an alkaloid, known as "biberine," is so remarkable
that the wood has earned a world-wide reputation. Greenheart
is one of the best of all construction timbers and, although seldom
seen in the United States, is used abroad for docks, bridges, keels,
rollers, flooring, wagons, carriage-shafts, furniture, and belaying-
pins. All of the gates, piers, and jetties of the Liverpool Docks,
and the lock gates of the Bridge water and Manchester Canals,
were built of this wood. Pieces used in the construction of the
Canada Dock, which was built in 1856, were used again in the
reconstruction of that work in 1894. Greenheart was specified
for the sills and fenders of the lock gates of the Panama Canal.
The Antarctic ship, Discovery, and Nansen's ship, The Fram,
were built of it.1

^ee also "Greenheart," Mell and Brush (United States Forest Service,
Circular, No. 211); "Greenheart Used in Panama Canal, etc." Armstrong
(Engineering Record, Vol. 73, Nos. 5 and 6, pp. 149 and 180); "The Green-
heart of Commerce," Mell (American Forestry, May, 1916).

BROADLEAF TRUNKS AND WOODS 201

Greenheart. Nectandra rodioei

NOMENCLATUKE (Mell and Brush).1
Greenheart (local and common name).
Sipiri, Bebeeru, Bibiru, Supeira (native Indian names).
Torchwood.

LOCALITIES.

British, Dutch, and French Guiana, some adjacent parts of South Amer-
ica, and the West Indies. It is seldom found more than fifty miles, and
never found more than one hundred miles, from the coast.

FEATURES OF TREE.

Twenty-five to sometimes seventy feet in height; two to four feet in di-
ameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark green to chestnut brown, sometimes nearly black; clean;
straight-grained; free from knots; some pieces possess great beauty.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, tough, elastic, strong, and durable; repels termites and tere-
does; liable to split and splinter, and so requires care in seasoning and
working; receives a high polish; withstands wear.

REPRESENTATIVE USES OF WOOD.

Abroad, the wood is used in docks, ships, machine parts, piles, trestles,
bridges, floors, wagons, carriage-shafts, furniture, and belaying-pins.
In the United States, it is occasionally used in veneers, automobile
spokes, turnery, and in the tips of fishing rods.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

72 (Laslett).
MODULUS OF ELASTICITY.

1,090,000 (Laslett).
MODULUS OF RUPTURE.

10,000 (Thurston).
REMARKS.

The Yellow, Gray, and Black varieties recognized by dealers come from

the same species, the distinctions being due to differences in the ages

and environment of the trees from which the several kinds were cut.

Black Greenheart resembles Lignumvitse and is valued more highly than

the others.1

^ee also "Greenheart," Mell and Brush (United States Forest Service,
Circular No. 211).

202 ORGANIC STRUCTURAL MATERIALS

PERSIMMON EBONY OSAGE ORANGE CHERRY

Diospyros Toxylon Prunus

The Persimmon (Diospyros virginiana) grows in the eastern
and southern parts of the United States and is a member of the
Ebony family (Ebenacece). The trees may be known by their
fruit, which is remarkably astringent when green, but sweet and
palatable when ripe. The wood is tough and hard. The sap-
wood, which resembles fine-grained hickory, is of a light brown
color, while the thin heartwood is almost black. Persim-
mon wood is sometimes used for plane-stocks, shuttles, and
shoe-lasts.

The true Ebony (Diospyros ebenwri) grows in Ceylon, India,
and Siam. The Mexican Ebony (Diospyros ebenaster), which is
a native of India, has been cultivated in the tropics of the western
hemisphere, and in the Philippine Islands. The Madagascar
Ebony (Diospyros mespiliformis) is a native of tropical Africa,
and the Green Ebony (Diospyros chloroxylori) is a native of
southern India. There are other sources in this and other
genera. The Ebony of commerce, which is fine-grained, very
hard and heavy, more or less durable, and of a deep black color,
is used for veneers, cabinet work, and piano keys.

The Osage Orange or Bois d'Arc (Toxylon pomiferwri) grows
naturally in parts of Oklahoma, Arkansas, Texas, and Louisiana,
while transplanted trees have succeeded as far north as New
England. The more or less slender trees yield useless fruit which,
in size and general appearance, suggests the common orange.
The thin sapwood is of a light yellow color, while the thick heart-
wood is bright orange. The wood is very hard and strong. It
takes a beautiful polish and is worthy of much more attention
than it receives. The aborigines made bows and arrows of it,
whence the name Bois d'Arc.

The Wild Black Cherry (Prunus serotina) grows in many localities in
the eastern half of the United States, and bears small, purplish-black
cherries, that are sweetly bitter when ripe. The Cherry wood of commerce
is obtained from this species. The strong, clean, straight-grained, hard,
durable, fine, reddish colored wood is easily worked; it receives a high
polish, and is used in cabinet wood and indoor finish. It is often
stained so as to imitate mahogany, while it itself is often imitated by
staining the wood of the Sweet Birch (Betula lento). Wild Cherry bark
contains a bitter principal that is used in medicine.

BROADLEAF TRUNKS AND WOODS 203

Persimmon. Diospyros virginiana Linn.

NOMENCLATURE (Sudworth).

Persimmon (local and common Simmon, Possumwood (Fla.).

name). Plaqueminier (La.)-

Date Plum (N. J., Tenn.).

LOCALITIES.

Rhode Island to Florida, westward intermittently to Missouri and Texas.

FEATURES OF TREE.

Occasionally seventy feet in height; one to two feet in diameter; the soft,
plum-like fruit is astringent when green and sweet when ripe.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood dark brown or black; sapwood light brown, often with darker
spots; very thin heartwood; very close-grained; compact structure; the
medullary rays are conspicuous; resembles Hickory.

STRUCTURAL QUALITIES OF WOOD.
Hard, heavy, and strong.

REPRESENTATIVE USES OF WOOD.

Plane-stocks, shoe-lasts, etc.; prized for shuttles.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT

49.
MODULUS OF ELASTICITY.

1,110,000.
MODULUS OF RUPTURE.

12,400.

REMARKS.

The astringent properties of the unripe fruit are due to tannic acid.
The dark heartwood is not greatly developed in trees that are under
one hundred years old.

204 ORGANIC STRUCTURAL MATERIALS

I Madura aurantiaca Nutt

Osage Orange. { m i v D f

[ Toxylon pomiferum Raj.

NOMENCLATURE (Sud worth).

Osage Orange (local and common Hedge, Hedge-plant, Osage (111.

name). la., Neb.)-

Bois D' Arc (La., Tex., Mo.). Mock Orange (La.).

Bodark, Bodock (Kans.). Bow-wood (Ala.).

Yellow-wood, Osage Apple Tree
(Tenn.).

LOCALITIES.

Southern Arkansas, Oklahoma, and Texas; cultivated elsewhere, as in
Massachusetts, Pennsylvania, and Michigan.

FEATURES OF TREE.

Twenty to fifty feet in height; rarely beyond one and one-half feet in
diameter; the form of the useless fruit suggests that of the orange. The
trees survive when planted close together and the living trunks of trees
thus planted are often used as fence posts.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood bright orange, which turns brown on exposure; the sap wood
is light yellow; close-grained; the annual rings are clearly marked.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, very strong, flexible, and durable in contact with the soil;
receives a beautiful polish; shrinks in seasoning.

REPRESENTATIVE USES OF WOOD.

Fence-posts, piles, telegraph poles, railway ties, paving-blocks, occasion-
ally indoor decoration, wagon felloes, and machinery.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

48.
MODULUS OF ELASTICITY.

1,300,000.
MODULUS OF RUPTURE.

16,000.
REMARKS.

The Indians used this wood for bows. The early name, Bois D'Arc, has
been corrupted to Bow Dark or Bodark. Bodark wagon felloes are much
prized in arid regions where the rains are confined to a short season of
the year, and where the balance of the year is hot and dry. Under
such circumstances, wheels made of some other woods shed their tires
and are otherwise less satisfactory.

BROADLEAF TRUNKS AND WOODS 205

f Prunus serotina Ehrh.
Wild Black Cherry, Wild Cherry. < -n -,

\ Padus serotina

NOMENCLATURE (Sudworth).

Wild Black Cherry, Wild Cherry Rum Cherry (N. H., Mass., R. I.,

(local and common names). Miss., Neb.).

Black Cherry (Me., N. H., Vt., Whiskey Cherry (Minn.).

R. I., N. Y., Miss., Ky., Mich., Choke Cherry (Mo., Wis., la.).
Wis., Ind., Neb.).

LOCALITIES.

Eastern to central United States.

FEATURES OF TREE.

Forty to eighty feet in height; two to three or more feet in diameter; the
bark and pea-sized fruit contain a bitter principal.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood reddish brown; sapwood yellow; fine, straight grain; compact
structure.

STRUCTURAL QUALITIES OF WOOD.

Light, hard, strong, and easily worked.

REPRESENTATIVE USES OF WOOD.

Cabinet work and interior finish; preferred beyond many other woods as
a base upon which enamelled paints are to be applied.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

36.
MODULUS OF ELASTICITY

1,200,000.
MODULUS OF RUPTURE.

11,700.
REMARKS.

206 ORGANIC STRUCTURAL MATERIALS

MAHOGANY

Swietenia, Khaya, Soymida, Cedrela, etc.

The many botanical sources of the woods known as Mahogany,
may be grouped upon a geographical basis as they grow in
Central America, the East Indies and Africa.

Central American Mahogany was originally obtained from the
Mahogany (Swietenia mahagoni), but is now derived from other trees
as well, such as some of those of the genus Cedrela. Central Ameri-
can Mahogany was once divided as it came from the then Spanish
American possessions and from Honduras. The first was called
"Spanish Mahogany" and the last "Honduras Mahogany." Most of
the wood that comes from Mexico is named from the ports from
which it is shipped. There are thus, Frontera, and other kinds of
Mahogany. East Indian Mahogany is obtained, largely, from the
Mahogany (Soymida febrifuga). The African sources are very
numerous, a fact that explains the differences that exist in the quali-
ties of these woods. The most 'important source is the Mahogany
(Khaya senegalensis) , while other sources are the species Khaya
grandifolia and Entandrophrdgma candollei. Some Mahogany is
brought from the Philippine Islands.

Mahogany has been used to a limited extent in construction,
but is now so greatly valued as a decorative wood that it is used
for little else, save, occasionally, the hulls of small pleasure craft.
The decorative value of this wood is due to a combination of
appearance, working qualities, and durability. The appearance
of mahogany is influenced by its cellular structure and its warm
reddish color. The latter is often comparatively light at first;
but, usually, darkens eventually to characteristic tints, which,
however, are usually induced at once by means of stains. The
cellular structure of mahogany is not only beautiful of itself,
but is such as to respond to the stains and finishing processes
commonly applied. Mahogany works and glues well. It is
very durable; few woods shrink or distort less than Mahogany
after it is in place. It should be noted that woods produced in
different localities differ in grain and color from one another, and
that pieces cut from different trees in the same locality often
differ also. Beautiful grain effects are often seen where trunks
and branches join, and such pieces, known as "crotches," usually
bring very high prices.

BROADLEAF TRUNKS AND WOODS 207

The Spanish Cedar (Cedrela odorata) is not a true Cedar. In
spite of its name it is not even remotely related to the trees from
which the Cedar woods of commerce are ordinarily obtained.
The true Cedars are all Conifers, whereas this tree is a Dicotyle-
don, and belongs to the family which includes the mahoganies.2
Aside from this the wood suggests fine Cedar in appearance, and
possesses the odor that is associated with that wood. It is used
for cigar boxes and cabinet work.

The Prima vera or White Mahogany (Tabebuia donnell-
smithii) is related to the Catalpas, and grows in Mexico and
Central America, where it is often associated with the true
Mahogany (Swietenia mahagoni). The wood resembles true
Mahogany, save in color, which is a light yellow that darkens
with age. The characteristic color of the finished wood is golden-
yellow. It is hard to find large pieces of Prima vera free from
worm holes. The wood is used in car finish, cabinet work, and
fine furniture, where ordinary Mahogany might be used, save
for its darker color.

1 The name Mountain Mahogany is applied to several trees that grow in
the Rocky Mountain region and yield woods that are sometimes employed
for fuel. Some of these species are Mountain Mahogany (Cercocarpus
ledifolius), Mountain Mahogany; Valley Mahogany (Cercocarpus parvi-
folius), Mountain Mahogany; Birchleaf Mahogany (Cercocarpus parvifolius
betuloides).

2 Meliacese has been divided into Swietenice, which includes some of the
true Mahoganies, and Cedreloe, which includes about nine genera and twenty-
five species, distributed over tropical Asia and America. See also "True
Mahogany," Mell (United States Department of Agriculture Bulletin No.
474, 1917).

208 ORGANIC STRUCTURAL MATERIALS

Mahogany. Swietenia mahagoni Jacq.

NOMENCLATURE.

Mahogany (local and common Mexican Mahogany (Frontera, and

name). other Mexican ports).

Spanish Mahogany (Cuba, San Honduras Mahogany (Honduras).

Domingo, West Indies). Bay wood, Madeira, Redwood.

LOCALITIES.

Florida Keys, the Bahamas, the West Indies, Mexico, Central America,
and Peru.

• FEATURES OF TREE.

Florida specimens are forty-five feet in height and two or more feet in
diameter; foreign trees are larger.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

Heartwood light, rich reddish brown; the thin sapwood is yellow; smooth,
fine, uniform texture; inconspicuous rings; the conspicuous pores are
sometimes filled with white substance.

STRUCTURAL QUALITIES OF WOOD.

Strong and durable, but brittle; it holds glue, takes stains, and receives a
high polish; it changes but little in seasoning and stands well.

REPRESENTATIVE USES OF WOOD.

Veneers and cabinet-work; was formerly used in ship-building.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

45.
MODULUS OF ELASTICITY.

1,510,000.
MODULUS OF RUPTURE.

14,000.
REMARKS.

The desirability of Mahogany from this and other species varies with
locality. Mahogany is usually stained,

BROADLEAF TRUNKS AND WOODS 209

Spanish Cedar, Mexican Cedar. Cedrela odorata Linn.

NOMENCLATURE.

Spanish Cedar, Mexican Cedar, Cuban Cedar (local and common names).

LOCALITIES.

Mexico, Cuba, and the West Indies.

FEATURES OF TREE.

Fifty to eighty feet in height; two to five feet in diameter; pale yellow
flowers ; there are pods that suggest pecan nuts as to form ; the form of
the tree suggests that of the English Walnut (Juglans regia).

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood brownish red; straight, even, compact grain.

STRUCTURAL QUALITIES OF WOOD.

Soft, fragrant, porous, and durable; resembles Cedar woods which are
derived from coniferous trees, and also resembles Mahogany.

REPRESENTATIVE USES OF WOOD.

Cigar-boxes, boats, and sometimes cabinet-work; may be used in place of
Mahogany.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
MODULUS OF ELASTICITY.
MODULUS OF RUPTURE.

REMARKS.

The trees grow rapidly. The related Australian Red Cedar (Cedrela aus-
tralis) is locally used for furniture, joinery, carriages, ceilings, and door
frames. These woods must not be confused with true cedars, which
are derived from non-related trees of the coniferous series.

The Toon Cedar (Cedrela toona Roxburgh} of the Orient is the same as the
Red Cedar (Cedrela australis F. v. M.}. of Australia. The Cedar (Cedrela
odorata Blanco} is thought to be a distinct Philippine species.

210 ORGANIC STRUCTURAL MATERIALS

White Mahogany. Tabebuia donnett-smithii Rose

Prima vera.

NOMENCLATURE.

White Mahogany, Prima vera Jenicero,
(local and common names) Genesero,

Roble.

LOCALITIES.

Southern States of Mexico to Peru.

FEATURES OF TREE.

Fifty to ninety feet in height; two to four feet in diameter; trunks are often
clear for thirty or forty feet from the ground; numerous golden-yellow
flowers precede the leaves; a beautiful tree.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

The heartwood is of a cream white color which often darkens with expo-
sure; the thin sapwood is almost white; beautiful mottled or clouded
effects usually seen best when pieces are quarter sawn; fine grained;
the wood resembles mahogany save in color.

STRUCTURAL QUALITIES OF WOOD.

Moderately heavy, tough, rather soft and not strong; dries without check-
ing, works well and stands well; receives stains and retains high polish;
durable in contact with the soil.

RFPRESENTATIVE USES OF WOOD.

Local constructions and railway ties; widely used for cabinet-work and
fine furniture; veneers.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

28. (reported).
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

REMARKS.

The wood can be used where fine, light colored, cheerful effects are
required; or it can be stained so as to imitate ordinary mahogany.
The wood of the butternut or white walnut is sometimes sold as white
mahogany but is seldom if ever seriously confused with the true wood.1

aSee also Botanical Gazette (Vol. XVII, 1892, p. 418) ; Contribution,
United States National Herbarium (Vol. I, No. 9, p. 346).

BROADLEAF TRUNKS AND WOODS 211

TEAK

Tectona, Oldfieldia

The Indian Teak (Tectona grandis) grows in India, Burmah,
the Malay Peninsula, Sumatra, Java, and Ceylon, and is a very
important tree that is sometimes referred to as the "Oak of the
East Indian forests." The less plentiful African Teak (Old-
fieldia africana) is a native of western tropical Africa. These two
trees are not related to one another, yet they yield woods that
possess the same anatomical characteristics.

Teak wood is fairly hard and heavy. The colors of freshly
cut pieces vary from light yellow to brownish red. Older pieces
are much darker. Teak contains a peculiar resin which probably
contributes to durability for which this wood is noted. This
resin also serves because it is obnoxious to insects and because it
preserves iron fastenings. Teak was long regarded as one of the
best of all woods for ship-building. It is now used in many
local constructions, such as railway ties, bridge-timbers, and
artillery wagons. It is extensively exported to Great Britain.
The grain is such that the wood is often carved, and Teak wood
is now known in North America chiefly through such carvings.1

1 See also "Wood, " Boulger (London, 2d Ed., p. 285.)

212 ORGANIC STRUCTURAL MATERIALS

Teak. Tectona grandis

NOMENCLATURE.

Teak. Teek.

Indian Oak. Sagwan.

LOCALITIES.

India, Burma, Siam, and Ceylon.

FEATURES OF TREE

Eighty to one hundred feet in height; three to four feet in diameter; some-
times larger; a straight trunk; large, drooping, deciduous leaves.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood is of a variable, brownish-yellow color; a straight, even-grained
wood.

STRUCTURAL QUALITIES OF WOOD.

Moderately hard, strong, and easily worked; stands well; oily, fragrant,
resists termites, and preserves iron.

REPRESENTATIVE USES OF WOOD.

Furniture, ship-building, timbers, and backing for armor-plates.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
50 (Laslett).

MODULUS OF ELASTICITY.
1,338,000 (Laslett).
2,100,000 (Thurston).

MODULUS OF RUPTURE.
15,000 (Thurston).

REMARKS.

It is thought that the properties by which iron fastenings are preserved,
and by which termites are repelled, are due to oil contained in the wood.
Burma Teak, Malabar Teak, and other kinds take their names from the
districts in which they were produced, or from which they were shipped.
Transplanted specimens have not succeeded well in California. The
distinct African Teak (Oldfieldia africana) yields a wood that is some-
times marketed as African Mahogany and African Oak.

BROADLEAF TRUNKS AND WOODS 213

Some other tropical species that yield widely known woods,
or other products, or that are valued in landscape work, are
as follows:

Sabicu (Lysiloma sabicu). — This West Indian wood is hard, heavy,
strong, and durable. It seasons and works well and has been used for
ships and furniture. The wood is of a dark chestnut-brown color.
Some pieces are highly figured. The appearance and the working quali-
ties of the wood are such that it may be used in place of rosewood.

Sissoo (Dalbergia sissoo) . — These trees grow in northern India. Some
transplanted specimens have succeeded in other places as California.
The wood, which is highly valued in India, is hard, heavy, strong, and
elastic. The sapwood rots quickly, but the heartwood remains sound
and hardens as the wood grows older. Sissoo seasons well and stands
well. It is used in wheels, boat-building, agricultural implements, and
furniture. Gun-carriage wheels made of Sissoo wood are highly prized.
Some pieces of Sissoo are almost as beautiful as pieces of rosewood. An
important source of commercial rosewood is related to the Sissoo.

The Rubber Tree. — The substance known as India rubber is like sugar
in that its constituents exist in a number of unrelated plants. These
constituents form part of a milky juice which is secreted by most of
the plants in question, and which is known as latex. Latex, which
is quite distinct from sap, is a thin, watery emulsion made up of cream-
like globules suspended in a thinner liquid of different composition; the
appearance of latex is similar to that of cows' milk. The latex of the
common milkweed is a familiar example. An exception to the rule that
rubber is obtained from latex is furnished by the Guayule plant. The
rubber obtained from this plant is distinct from most others in that it is
not obtained from latex but exists as such in the cells of the plants.

The trees, vines, and shrubs from which India rubber may be obtained
are numbered by the hundred, but the sources from which it is actually
obtained in commercial quantities are comparatively few. The prin-
cipal trees from which it is obtained are the Para or Hevea Rubber Tree
(Hevea braziliensis) the Central American Rubber Trees (Castilla
elastica and others) and the Assam Rubber Tree (Ficus elastica). The
wood of the rubber tree is seldom employed save locally. It should be
noted that the latex from which India rubber is obtained is secreted only
under favorable conditions. (See also Chapter XVII).

The Pepper, California Pepper or Peruvian Mastic (Schinus molle)
was introduced into California from Peru by the early Spanish mission-
aries, and is now one of the most popular shade trees on the Pacific
Coast, south of San Francisco. The Pepper tree grows to heights of
thirty to fifty feet. The outline suggests that of the Apple tree, while
the drooping foliage suggests the foliage of the Willow. There are long
sprays of rose-tinted berries, masses of slender, drooping branchlets,
and delicate, bright evergreen leaves that emit a pleasant, pungent

214 ORGANIC STRUCTURAL MATERIALS

odor. The berries are the size of currants or pepper corns, whence the
name Pepper tree. The soft, smooth, whitish-colored woods are seldom
employed, save for fuel. The California Pepper tree is the host of the
"black scale," and is now being replaced by the better, faster-growing,
Longleaved Pepper tree (Schinus terebinthifolius) from Brazil.

The Tung Oil Tree.— The Tung Oil tree (Aleurites fordii) , also known
as the Chinese Wood Oil tree, belongs to the family Euphorbiaceae. It
is associated with China, but is grown in other parts of the world, and
has succeeded, in the United States, in southern California, and in the
region that extends southward from Cairo, Georgia. It grows to a
height of thirty or more feet and has an ornamental value about equal
to that of the Cat&lpa. The flowers precede the leaves and cause the
tree to be very beautiful when in bloom. The soft wood is not valuable;
but the fruit, which suggests an apple two or three inches in diameter,
contains from two to eight large seeds from which the Tung oil of com-
merce is obtained. The tree begins to bear fruit when four or five years
old. It is said that, in China, a tree yields from thirty to seventy-five
pounds of seed every year.1

The Balsa (Ochroma lagopus). — This native of Central America and
the West Indies attains a diameter of about one foot. The large, broad
leaves resemble those of the Catalpa. The weak, uniform, spongy, par-
enchymatous wood is free from knots and checks and is so soft that it
can be indented with the finger nail. It is one of the lightest of all
woods, its weight of seven pounds per cubic foot being half that of
ordinary cork. It does not last well; and it absorbs water so readily
that it soon becomes water logged unless impregnated with paraffin or
some similar compound. It is extremely porous, and for this reason
is an excellent insulator against heat and cold. Balsa wood is used in
refrigerator linings, and, after treatment with paraffin, is used in life
preservers in place of cork. It is used locally for canoes.2

The China or China-berry (Melia azedarach) is a native of India,
China, and some other parts of the eastern hemisphere, but is now grown
successfully in many parts of the world, including districts in the south-
ern part of the United States. The China tree is also referred to as the
Pride of India, the Bead tree, and the Umbrella tree. The short,
straight trunk merges abruptly into numerous branches that radiate
outward like the ribs of an umbrella. The peculiar form, rapid develop-
ment, and thick, handsome foliage cause the true to be valued in land-
scape effects, wherever it will grow. The wood, which is sometimes
improperly referred to as "White Cedar" and "Bastard Cedar," is oc-
casionally made into furniture. The berries contain pits that are some-
times used as beads.

The Rosewood. — There are many "Rosewood trees." The African
Rosewood (Pterocarpus erinaceus) grows in tropical western Africa. The
Brazilian Rosewood (probably Dalbergia nigra) is a native of Brazil.
The Canary Rosewood (Convolvulus scoparius) grows in the Canary

BROADLEAF TRUNKS AND WOODS 215

Islands. In California, rosewood is derived from the stems of very
large rose bushes. Commercial rosewood is hard, tough, fine grained,
and compact. The colors vary from rich reds to chestnut browns;
there are often black streaks and sometimes purplish effects. The name
Rosewood is due to the more or less pronounced scent of roses which the
woods emit. The wood is also known by other names, as Blackwood
and Bloodwood. Rosewood is sometimes used in local constructions,
but is normally seen in costly furniture, piano cases, burial caskets, and
panel work. It is sometimes associated with Circassian Walnut and
Satinwood in the decorative work in compartment cars. An oil, dis-
tilled from one of the species from which commercial rosewood is ob-
tained, has been used to adulterate attar of roses.

The Sandalwood. — The Sandalwood of commerce is obtained from
many botanical sources. The genus Santalum alone includes about
twenty species. Until the eighteenth century, Sandalwood was ob-
tained from China. The discovery of sources on the Islands of the
Pacific led to lawless traffic and much bloodshed. The adventures
associated with the collection of this wood were equal to those encoun-
tered in whaling and the search for ivory. The Sandalwood tree (San-
talum album) yields a reddish-brown, close-grained, very fragrant wood
that weighs about fifty-five pounds a cubic foot. Red Sandalwood or
Sanderswood (Pterocarpus santalinus) yields a red dye that is known as
"santalin." Sandalwood was prized by the French nobility for medal-
lions that were mounted on otherwise decorated surfaces. It was also
sometimes made into rich furniture, and is now occasionally seen in
finely carved small objects, as jewel boxes and fan handles. The
powdered wood is burned as incense. A fragrant oil is separated by
distillation.

Satinwood. — The East Indian Satinwood (Chloroxylon swietenia), grows
in India and Ceylon, while the Yellow-wood or Satinwood (Xanthoxylum
cribrosum) is a native of Florida and the West Indies. There are other
botanical sources. The yellow or orange-colored woods are hard, heavy,
close-grained, durable, and beautifully figured. Pieces from San Domingo
and Jamaica are particularly beautiful and bring the highest prices.
Satinwood is very valuable and is seldom used, save in the finest cabinet
work and furniture.

A valuable list has been prepared by Mell under the title " Cabinet
Woods of the Future."3

1 "The China Wood Oil Tree," Fairchild (United States Bureau of Plant
Industry, Circular No. 108); Files of "Oil, Paint and DrugReporter;" etc.

2 Missouri Botanical Garden Bulletin (August, 1915, p. 107); The Prop-
erties of Balsa wood," Carpenter (Proceedings, American Society Civil
Engineers, May, 1916).

3 "Cabinet Woods of the Future," Mell (American Forestry, Vol. XVI,
No. 12.

216 ORGANIC STRUCTURAL MATERIALS

EUCALYPTUS

Eucalyptus

The Eucalypts, locally known as Stringybarks, Ironbarks,
Mahoganies, Box and Gum trees, are natives of Australia and the
neighboring islands.1 The genus is now represented by culti-
vated specimens on each of the continents, where, in some places,
it has influenced topographical and other conditions to a remark-
able degree2. The Riviera, the Campania, the Nilgheri Hills
in southern India and parts of Algeria, Brazil, and California
have been practically transformed by Eucalyptus trees.

Eucalyptus trees are noted for their rapid growth, fine appear-
ance, great size, tough and durable woods, and their influence
upon sanitation.

Rapid Growth. — This is shown by specimens of the Blue Gum (Euca-
lyptus globulus) that have lengthened more than two feet in a single
month. In three years, a tree of this species attained a diameter of
about nine inches. A Pasadena tree was five feet thick at the end of
twenty-five years, while some specimens in Santa Barbara that were
twenty-five years old compared in general development with oaks that
were over two hundred years old.

Appearance. — The trees of some species are very attractive in form.
Some of the trees blossom during droughts when other flowers are scarce;
others blossom twice a year; and still others blossom all the time.

Size. — The enormous size is seen in specimens of the Peppermint tree
(Eucalyptus amygdalina} that have grown to heights of over four hun-
dred feet and are the tallest, although not the largest, trees known to man.

Character of Woods. — Eucalyptus woods are tough and hard to season
but some of them are very valuable. The working qualities of Aus-
tralian grown Jarrah, Karri, Tuart, and Red Gum woods (Eucalyptus
marginata, Eucalyptus diversicolor, Eucalyptus gomphocephala, and Euca-
lyptus rostrata) are such that these woods are highly prized in many
localities. In London and in Paris, blocks of Jarrah and Karri woods
have been used to pave streets subjected to heavy traffic.

REFERENCES. — Works of von Mueller; Report J. Ednie Brown, Forest
Commissioner of Western Australia; Works of Abbot Kinney (Press Baum-
gardt, Los Angeles); Ingham (California State Agricultural Experiment
Station, Bulletin No. 196); "Eucalypts Cultivated in the United States,"
McClatchie (United States Bureau of Forestry, Bulletin No. 35, 1902);
' 'Utilization of California Eucalypts, "Betts and Smith (United States Forest
Service, Circular No. 179); "Eucalypts in Florida," Zon and Briscoe (United
States Forest Service, Bulletin No. 87, 1911); "Yield and Returns of Blue
Gum in California," Woodbury (United States Forest Service, Circular
No. 210); "Eucalypts," Pinchot (United States Forest Service, Circular
No. 59 Revised, 1907).

BROADLEAF TRUNKS AND WOODS 217

Influence upon Health. — Improvement in the health of residents has
followed the introduction of the Blue Gum (Eucalyptus globulus} in
malarial districts such as some in the vicinity of Rome. It is possible
that these fortunate results may have been influenced to a slight extent
by medicinal compounds in the foliage, but it is much more probable
that they were due to the fact that the leaves of this species evaporate
large quantities of water, and thus reduce the moisture conditions neces-
sary for the growth of mosquitoes.

The genus may be summarized from the viewpoint of the living
tree and from the viewpoint of the woods as follows :

Eucalyptus Trees Grow Rapidly. — Some of them grow where those of
other species will not; some form windbreaks and forest cover; some
serve in landscape effects; some afford honey and many yield oils.
The hard, tough woods present an unusual range of possibilities. Mc-
Clatchie enumerates twenty-five ways in which these woods have been
used in Australia : six species are valued for bridge timbers, five for piles,
nine for paving, eight for posts, three for railway ties, four for car build-
ing, five for lumber and shingles, seven for carriage parts, two for cooper-
age, and two for handles. Thus far, comparatively little eucalyptus
lumber has been produced in this country, but experience is sufficient
to show that some kinds of eucalyptus can be used in place of other
woods that are now used in the United States for piles, posts, poles,
crossties, mine timbers, paving blocks, insulator pins, furniture, finish,
veneers, cooperage, vehicle stock, and tool handles. Eucalyptus woods
are hard to season. The structure is complicated and the woods are
full of water. This is particularly true of woods produced in the United
States where the trees are yet comparatively young. No really sat-
isfactory method of seasoning the woods of the species thus far intro-
duced into North America has yet been worked out on .a commercial
basis. The colors of the woods vary; shades of yellow, brown and
red predominate.

The evergreen leaves exhibit many tints, normally of the colors
gray, blue, and green. The characteristic odor is the only point in
common between the leaves of young and old trees of some species.
The genus includes nearly two hundred and fifty species.

1 The nomenclature is confusing. There are eleven Stringybarks, eight
Ironbarks, nine Red Gums, and twelve Blue Gums. The Blue Gum
(Eucalyptus globulus) is the species commonly referred to when the Eucalyp-
tus is mentioned in North America.

2 Eucalyptus trees do not grow well in the United States outside of Cali-
fornia, Arizona, New Mexico, Texas, and Florida and their success in New
Mexico, Texas, and Florida has not been remarkable. The Florida climate
is favorable most but not all of the time. The climate of Southern Cali-
fornia is more equable and this district must still be regarded as the only
real North American locality.

218 ORGANIC STRUCTURAL MATERIALS

Blue Gum, Fever Tree. Eucalyptus globulus

NOMENCLATURE.

Blue Gum (local and common name). Fever Tree, Balluck (Australia).

LOCALITIES.

Native of Australia; acclimated in southern California and elsewhere in
frostless regions throughout the world.

FEATURES OF TREE.

Sometimes three hundred or more feet in height; three to six feet in di-
ameter; bark varies with age and environment; the form and color of the
leaves which are sometimes twelve inches in length, vary with age;
characteristic odor/

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood straw color; sap wood lighter; complicated cellular arrange-
ment; indistinct annual rings.

STRUCTURAL QUALITIES OF WOOD.

Hard and heavy; the cellular structure is such that the wood is hard to
split and work after it has been seasoned ; the American product is hard
to season, possibly because the trees are comparatively young and full
of water. Not durable in contact with the soil.

REPRESENTATIVE USES OF WOOD.

Principal experience is abroad, where foreign-grown pieces are used for
rollers, paving-blocks, ship-building, carriage parts, and fuel. In the
United States, pieces boiled in water, and then in linseed oil, are used
for insulator pins on telegraph poles; in California, the wood is used for
piles and mine-timbers; an important fuel in southern California.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
43 to 69 (Mueller). 57 to 69 (Laslett). 47.9 (Betts & Smith).1

MODULUS OF ELASTICITY.

1,712,000 (Average of 17 tests of California-grown specimens).1

MODULUS OF RUPTURE.

12,400 (Average of 17 tests of California-grown specimens).1

REMARKS.

It should be noted that the name Blue Gum is applied to at least eleven
other species. This Blue Gum is the Eucalyptus of California.

1 United States Forest Service, Circular No. 179, p. 12.

BROADLEAF TRUNKS AND WOODS 219

Red Gum. Eucalyptus rostrata

NOMENCLATURE.

Red Gum (local and common name).

LOCALITIES.

Australia. Acclimated in California and elsewhere.

FEATURES OF TREE.

One hundred or more feet in height; the tress are often crooked; the bark,
when young, is red.

COLOR, APPEARANCE, OR GRAIN OP WOOD.

The color of the heartwood varies from light red to dark blood-red;
the color darkens with age; close-grained; the cellular arrangement is
complicated.

STRUCTURAL QUALITIES OF WOOD.

Strong, hard, and heavy; said to resist attacks of shipworms and termites;
pieces cut from American trees are hard to season ; capable of receiving a
high polish.

REPRESENTATIVE USES OF WOOD.

Principal experience is abroad, where foreign-grown pieces are Used for
posts, bridge-timbers, short beams, ship-timbers, ties, and paving-
blocks.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
55.6.1

MODULUS OF ELASTICITY.

1,201,000 (Average of 9 tests on California-grown specimens).2

MODULUS OF RUPTURE.

12,369 (Average of 9 tests on California-grown specimens).2

REMARKS.

A Commission on State Forests and Timber Reserves in Melbourne gave
as its opinion that Red Gum is the "most important tree in the State, on
account of its durability and the many uses to which it (the wood)
is put." Von Mueller wrote of Red Gum as "perhaps the most im-
portant of the entire genus." The best grade of lumber is obtained
from trees over one hundred years of age. It is believed that Red
Gum trees will succeed well in California, but the wood thus far pro-
duced in that region is hard to season, possibly because the trees are
comparatively young and full of water.

1 United States Forest Service, Circular No. 179, p. 28.

2 United States Forest Service, Circular No. 179, p. 16 and 28.

220 ORGANIC STRUCTURAL MATERIALS

Jarrah. Eucalyptus marginata

NOMENCLATURE.

Jarrah (local and common name).
Mahogany Gum (Australia).

LOCALITIES.

Western coast of Australia; some specimens acclimated in California.

FEATURES OF TREE.

Ninety to one hundred or more feet in height; two to five feet in diameter;
branches concentrated at tops of trees.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

The reddish-brown wood resembles Mahogany; it also resembles Kauri
wood.

STRUCTURAL QUALITIES OF WOOD.

Heavy, somewhat oily, -non-absorbent, does not take fire easily, durable
in contact with the soil; it may be polished; it wears thin evenly, and is
said to repel marine and land wood-borers.

REPRESENTATIVE USES OF WOOD.

Ship-building, dock and bridge-timbers, paving-blocks.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
65 (Ednie-Brown).1

MODULUS OF ELASTICITY.
2,080,000 (Ednie-Brown).1

MODULUS OF RUPTURE.
8,900 (Ednie-Brown).1

REMARKS.

The principal timber tree of southwestern Australia. The wood is often
confused with that of the Karri, von Mueller calls it the least inflam-
mable of woods.

1 Report on Forests of Western Australia, Presented to Parliament, 1896.

BROADLEAF TRUNKS AND WOODS 221

Karri. Eucalyptus diversicolor

NOMENCLATURE.

Karri (many localities). White Gum (Australia).

LOCALITIES.

Australia and New Zealand; some specimens acclimated in California.

FEATURES OF TREE.

Sometimes three hundred and fifty feet in height; from four to eighteen
feet in diameter; a straight, graceful tree, the lower branches of which
are often one hundred and fifty feet from the ground; smooth, yellow-
white bark.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Heartwood is reddish-brown; complicated cellular arrangement.

STRUCTURAL QUALITIES OF WOOD.

Hard, heavy, tough, elastic, non-absorbent, and durable; difficult to work;
wears evenly; possesses a characteristic odor.

REPRESENTATIVE USES OF WOOD.

Heavy timbers, railway ties, piles, marine work, paving-blocks, masts,
and lumber.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

63 (Ednie-Brown).1
MODULUS OF ELASTICITY.

2,890,000 (Ednie-Brown).1
MODULUS OF RUPTURE.

8,000 (Ednie-Brown).1
REMARKS.

The name diversicolor is due to the fact that the upper and lower sides of
the leaves differ in color from one another. It should be noted, how-
ever, that this characteristic is not confined to this particular species of
this one genus. The Karri was once named Eucalyptus colossea because
of its great size. This Karri is quite distinct from the Kauri (Dammara
australis).

Report on Forests of Western Australia, Presented to Parliament, 1896.

222 ORGANIC STRUCTURAL MATERIALS

Tuart. Eucalyptus gomphocephala

NOMENCLATURE.

Tuart (local and common name). Tooart (Australia).
Tewart (Australia). White Gum (Australia).

LOCALITIES.

Australia; acclimated elsewhere.

FEATURES OF TREE.

Sometimes one hundred and fifty feet in height; four to six feet in di-
ameter; a straight trunk, with grayish-white bark; bright, cheerful
appearance.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

The heartwood is of a light-yellow color; close-grained; the cellular
arrangement is complicated.

STRUCTURAL QUALITIES OF WOOD.

Strong, tough, rigid, hard, heavy, and durable; seasons well; is hard to
split and work.

REPRESENTATIVE USES OF WOOD.

Keele, buffers, stern-posts, frames, wheel-hubs, and shafts.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

67 (Ednie-Brown).1
MODULUS OF ELASTICITY.

2,300,000 (Ednie-Brown).1
MODULUS OF RUPTURE.

9,300 (Ednie-Brown).1
REMARKS.

In California, trees have reached heights of eighty feet within twenty-four
years. The wood is one of the strongest of all those used in construc-
tion.

Report on Forests of Western Australia, Presented to Parliament, 1896.

BROADLEAF TRUNKS AND WOODS 223

Other important Eucalypts are as follows:

Sugar Gum (Eucalyptus corynocalyx) . — This is one of the Eucalypts
that has succeeded in California. The tall, erect trees resist drought,
but are less able than Red Gum trees to withstand frost. The trees
blossom profusely for several months. The hard wood is of a yellowish-
white color.

Giant Eucalypt or Peppermint Tree (Eucalyptus amygdalind) . — This is
the tallest, although not the largest, of trees known to man. The leaves
possess an odor that resembles that of peppermint. The woods are less
desirable than those obtained from other Eucalypts.

Manna Gum (Eucalyptus viminalis). — The usually erect trees resist
comparatively low temperatures almost as well as Red Gum trees.
They grow rapidly, are thrifty, and yield woods that vary in color from
light brown to yellowish- white.

Ironbark or Stringybark (Eucalyptus macrorrhyncha) . — The durable,
dark gray, fibrous bark is used locally for roofing, while fibers drawn
from the bark are used in making string. The hard, durable wood is
employed for lumber, shingles, and fuel.

Red Mahogany or Red Gum (Eucalyptus resinifera) . — This tree yields
a hard, heavy, durable, rich red wood, the appearance of which suggests
Mahogany. The wood is used for shingles, posts, piles, and paving-
blocks, and is suitable for use in furniture.

CHAPTER VIII

NON-BANDED TRUNKS AND WOODS
Monocotyledons

The trunks from which non-banded woods are obtained grow
in thickness from the inside. With several exceptions these
trunks increase principally by the expansion of cells already
formed.1 There are no layers or concentric bands, such as
characterize the woods of the other group. On the contrary,
the wood-elements are distributed in such a way as to appear
as dots over the cross-sections. The trunks normally attain
maximum diameters quite early, and, unlike Banded trunks, do
not continue to increase throughout their lives. The trunks are
enclosed by integuments that bear but slight resemblance to
bark. The few forms that yield structural woods are asso-
ciated with the tropics. Of these, the Palms and Bamboos are
examples.

The classes of wood-elements that exist in Non-banded woods
are the same as those that exist in Banded woods. Some classes
of cells may be modified as they exist in certain groups of Mono-
cotyledons, just as they are also modified in some groups of
Dicotyledons and Conifers; but, as far as known, there are no
cell forms that are peculiar to Non-banded woods alone. The
hardest parts of Non-banded stems are at their surfaces, while
the softest parts are at their centers. In many cases, as with
Bamboos, the tissues at the center are quite lacking.

The quantity of structural material obtained from the Mono-
cotyledons is comparatively small. Yet the group as a whole,
with some forty families, including numerous genera and about
twenty thousand species, is highly important. The grasses,
including corn, wheat, rye, sugar-cane and bamboo; and the
Palms, including many valuable trees, are of this group.

1 The Yucca and the Dragon-tree are Monocots which grow by a cambium
region just within the cortical region.

224

NON-BANDED TRUNKS AND WOODS 225

PALM

Palmacece

More than one thousand species of Palms, grouped in the
family Palmacese, are distributed over the tropical and semi-
tropical regions of the eastern and western hemispheres. The
Washington Palm (Washingtonia filif era), and several Palmettoes
(Sabal palmetto, Thrinax parviflora, etc.), yield woods that are
used in the United States; but the rule is, that the trees, rather
than the woods, are valued in this country.1

The wood is soft, light, weak, non-coherent, and more or less
porous. Large fiber-bundles contrast sharply with the surround-
ing tissue, and cause sections to present a spotted appearance (see
preceding figure 2). Palm wood is comparatively safe from
the attacks of shipworms, which are not " worms" but mollusks.
These mollusks line the surfaces of their tunnels with shell, for
which the weak and porous wood is, apparently, an insufficient
foundation.

The long leaf-stalks of the Washington Palm are worthy of
attention. The material of which these stalks are composed
resembles that of which Bamboo is composed. The stalks are
seldom used, although they present what is, weight for weight,
one of the strongest of all materials.

Two roughly cured stalks were tested. The central portions of each
specimen broke, leaving the edges, which stripped, without signs of
fracture. In one case the Modulus of Rupture was 11,370 and in the
other case it was 10,150. The figures were averaged for the entire sec-
tions, including the parts that stripped without breaking. The strength,
which would doubtless be increased by selection and appropriate season-
ing, is even more significant when the very light weight of the material
is remembered.

Sudworth2 enumerates the following palms as attaining to
the dignity of trees in the United States:
Sargent Palm (Pseudophcenix sar- Cabbage Palmetto (Sabal pal-

gentii) . metto) .

Fanleaf Palm (Washingtonia fill- Silvertop Palmetto (Thrinax mi-

fera) . crocarpa) .

Royal Palm (Oreodoxa regid). Silktop Palmetto (Thrinax parvi-

flora}.

Mexican Palmetto (Sabal mexi-
cand) .

1 Many Palms seen at pleasure resorts in the South have been transplanted
and are not native in those localities.

2 "Check List" (U. S. Forestry Bulletin No. 17).

226 ORGANIC STRUCTURAL MATERIALS

Washington Palm. Washingtonia fill/era Wendl.

Fan leaf Palm. Neowashingtonia filamentosa Wendl.

NOMENCLATURE (Sud worth).

Fanleaf Palm, Washington Palm, California Fan Palm, Arizona Palm,
Desert Palm (Cal.). Wild Date (CaL).

LOCALITIES.
California.

FEATURES OP TREE.

Thirty to sixty feet in height; one and one-half to three feet in diameter;
the fan-shaped leaves rise in a tuft from the summit of the trunk; the
largest of the United States palms.

COLOR, APPEARANCE, OR GRAIN OF WOOD.
Light greenish-yellow to dark red; unstable, fibrous, and coarse.

STRUCTURAL QUALITIES OF WOOD.

Soft, light, shrinks in seasoning, unstable, hard to work.

REPRESENTATIVE USES OF WOOD.
Fuel.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

32.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

REMARKS.

This is the most popular of the palms used in California for landscape
effects. The wood has but little value, but the light, tough, flexible,
and stringy leaf -stalks possess characteristics that are worthy of notice.
The results of experiments upon seasoned stalks are noted in the pre-
ceding introduction. The name "Wild Date" should not cause these
trees to be confused with true Date Palms (Phwnix dactylifera).

Date Palm (Phcenix dactylifera). These trees, which grow in semi-
tropical regions in the East, have been naturalized in Arizona, California,
and Florida. In the East, the Date Palm is valued not only because it
yields fruit, syrup, and vinegar, but because its wood is employed in car-
pentry and simple furniture; the leaves are used in making fans, baskets,
cord, and paper.1

1 "Arabia," Zwemer; Swingle (Year Book, United States Department of
Agriculture, 1900, pp. 453, 490); Tourney (Arizona Experiment Station,
Bulletin No. 29).

NON-BANDED TRUNKS AND WOODS 227

Cabbage Palmetto. Sahal palmetto Walt.

NOMENCLATURE (Sudworth).

Cabbage Palmetto, Palmetto Cabbage Tree (Miss., Fla.).
(N. C., S. C.). Tree Palmetto (La.).

LOCALITIES.

Central- Atlantic, South Atlantic, and Gulf Coasts of the United States;
the West Indies.

FEATURES OF TREE.

Thirty to forty feet in height; one to two and one-half feet in diameter.

COLOR, APPEARANCE, OR GRAIN OF WOOD.
Light brown; fibrous and coarse.

STRUCTURAL QUALITIES OF WOOD.

Soft and light; repels marine wood-borers.

REPRESENTATIVE USES OF WOOD.
Used locally for piles and docks.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

27.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.
REMARKS.

Other Palmettoes grow in the United States. Among them are the
Silver Thatch or Silktop Palmetto (Thrinax parvi flora), the Prickly Thatch
or Silvertop Palmetto (Thrinax microcarpa), and the Mexican Palmetto
(Sabal mexicana).

228 ORGANIC STRUCTURAL MATERIALS

YUCCA

Yucca

This genus includes about thirty species and many varieties.
Of the species which grow in the United States, the Tree Yucca
or Joshua tree and eight others assume the habit and attain the
size of small trees. The Yuccas are among the exceptional Mono-
cotyledons that increase in diameter through the instrumentality
of a cambium layer.1 Several of the Yuccas are cultivated
because of their beautiful lily-like flowers.

Yucca wood is coarse and fibrous. Direct vertical cleavage
is lacking. The fibers interlace so that thin sheets of rotary cut
wood can be selected which bend almost as readily as thick felt.
Yucca wood is used in special objects such as souvenirs, splints
and artificial limbs. Eight species noted by Sudworth are as
follows :

Joshua tree (Yucca arborescens) . Aloe-leaf Yucca (Yucca aloifolid).

Spanish Bayonet (Yucca trecu- Broadfruit Yucca (Yucca macro-

leana) . car pa} .

Spanish Dagger (Yucca gloriosa). Schott Yucca (Yucca brevifolia).

Mohave Yucca (Yucca mohaven- Yucca (Yucca constricta}.

sis) .

See also "Textbook of Botany," Strasburger (p. 145).

NON-BANDED TRUNKS AND WOODS 229

Yucca arbor escens Ton.

Joshua-tree, Yucca.

NOMENCLATURE (Sudworth).

Joshua-tree, The Joshua, Yucca, Yucca Cactus (Cal.).
Yucca Tree (Utah, Ariz., N. M.,
Cal.).

LOCALITIES.

Central and Lower Rocky Mountain region.

FEATURES OE TREE.

Twenty-five to forty feet in height; six inches to two feet in diameter; a
thick, outer cover or bark.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Light brown to yellowish white; fibrous and coarse; interlaced cellular
arrangement.

STRUCTURAL QUALITIES OF WOOD.

Light, soft, and spongy; flexible in thin sheets.

REPRESENTATIVE USES OF WOOD.

Small objects, as souvenirs; paper-pulp, splints and artificial limbs.

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.

23.
MODULUS OF ELASTICITY.

MODULUS OF RUPTURE.

REMARKS.

Artificial limbs are made by bending veneers of Yucca wood over moulds;
strong cements are employed, and the forms that result are strong,
tough, and very light. The sheets of flexible Yucca which are sold in
souvenir stores are rotary cut.

230 ORGANIC STRUCTURAL MATERIALS

BAMBOO

Bambusa

These giant grasses grow in China, Japan, and other tropical
and semi-tropical regions, and, in some places, even extend over
into the temperate zone. In the United States they have suc-
ceeded as far north as the Carolinas.1- 2

Bamboo stems often attain heights of seventy feet and diame-
ters of five or six inches. They grow with surprising rapidity;
a Philippine specimen grew two feet in three days,3 while some
Florida specimens reached heights of seventy-two feet in a single
season. The stems of Bamboo may be compared with those of
asparagus, in that both are more or less tender when young, and
much more hard and fibrous when old. Stems that grow in a few
weeks may require three or four years to season or harden.

Those who use bamboo value it highly. The pieces are
often employed without splitting. Sometimes, while yet green,
they are split and flattened into rough boards, which, although
they split everywhere nevertheless hold together. Johnson
notes that " Bamboo is just twice as strong as the strongest wood
in cross-bending, weight for weight, when the wood is taken in
specimens with square and solid cross-sections."4 The manipu-
lation of this valuable material is not yet understood in the
United States, but some of the many ways in which it is used
abroad are summarized as follows:5

"The Chinese make masts of it for their small junks, and twist into
cables for their larger ones. They weave it into matting for floors,
and make it into rafters for roofs. They sit at tables on bamboo chairs,
eat shutes of bamboo with bamboo chop-sticks. The musician blows
a bamboo flute, and the watchman beats a bamboo rattle. Criminals
are confined in a bamboo cage, and beaten with bamboo rods. Paper
is made of bamboo fiber, and pencils of a joint of bamboo, in which is
inserted a tuft of goat's hair."

1 "Grasses. This is one of the largest and probably one of the most use-
ful groups of plants, as well as one of the most peculiar. It is worldwide in its
distribution, and is remarkable in its display of individuals, often growing so
densely over large areas as to form a close turf. If the grass-like sedges be
associated with them there are about six thousand species, representing
nearly one-third of the Monocotyledons. Here belong the various cereals,
sugar canes, bamboos, and pasture grasses, all of them immensely useful
plants" ("Plants," Coulter, pp. 240-241).

NON-BANDED TRUNKS AND WOODS 231

2Fernow notes that "In addition to the genus Bambusa, the genera
Arundinaria, Arundo, Dendrocalamus, and Guadua are the most important"
(United States Forestry Bulletin No. 11, p. 29).

3 "Inhabitants of the Philippines," Sawyer (Scribner, 1900, p. 5).

4 "Materials of Construction" Johnson (John Wiley & Sons, 1897, p. 689).

5 "Cycle of Cathay," Martin (Fleming H. Revell Company, 1899, p. 172).
See also "New Granada," Holton (Harper Bros., 1857, p. 109); "Bamboo
and its Uses," Kurz (Calcutta, 1876); "The Bamboo Garden," Mitford
(Macmillan, 1896); "Japanese Bamboos," Fairchild (United States Bureau
Plant Industry, Bulletins Nos. 42-43) ; etc., etc.

232 ORGANIC STRUCTURAL MATERIALS

Bamboo. Bambusa vulgaris

NOMENCLATUEE.

Bamboo (local and common name).

LOCALITIES.

Widespread throughout the tropics and semi-tropics; acclimated in
Florida.

FEATURES OF TREE.

Seventy-five feet in height; four to six inches in diameter; glazed, greenish,
jointed stems, delicate branches and leaves; extensive roots.

COLOR, APPEARANCE, OR GRAIN OF WOOD.

Yellowish brown; fibrous and coarse; moderately thin walls surround cen-
tral canals which are broken by joints.

STRUCTURAL QUALITIES OF WOOD.
Light and elastic; works easily.

REPRESENTATIVE USES OF WOOD.

Posts, poles, troughs, pies, utensils, roofing, frames of aeroplanes, and

paper.

»

WEIGHT OF SEASONED WOOD IN POUNDS PER CUBIC FOOT.
Variable.

MODULUS OF ELASTICITY.
2,380,000 (Johnson's "Materials of Construction," p. 689).

MODULUS OF RUPTURE.
27,400 (Johnson's " Materials of Construction," p. 689).

REMARKS.

Bamboos are not trees, although they are as tall as trees, but may be
described as wood-producing grasses. Bamboos grow rapidly. A stem
may reach its full height in a single year, but must then stand for
three or four years in order to season and harden.

Rattan. Rattan is obtained from several sources. One species (Calamus
rudentum) is a climber, the stalks of which although not over one inch in
thickness, are sometimes three hundred or more feet in length as they fall and
ascend in festoons from tall trees. Another species (Rhapis flabelliformis)
yields erect canes which grow in thick tufts. Pieces obtained from both
climbing and ground rattans are tough, light, long, strong, and pliable.
Locally, rattan is used for making houses, bridges, matting, hats, baskets,
and cordage. In most civilized countries, split rattan is superseding willow
for furniture, fancy carriage bodies, chair bottoms, and the like. The best
rattan comes from Borneo.

CHAPTER IX

SPECIAL PROPERTIES OF WOODS DUE TO THEIR ORGANIC ORIGIN.
CHEMICAL COMPOSITION OF WOODS. PHYSICAL PROPER-
TIES OF WOODS: DESCRIPTIONS OF WEIGHTS AND MODULI
EMPLOYED. MOISTURE IN WOODS; INFLUENCE OF MOIS-
TURE, ANTISEPTICS, AND HEAT UPON THE PHYSICAL PROP-
ERTIES OF WOODS

All materials are studied from the viewpoints of chemical
composition and of physical properties, but organic materials
are also studied from the viewpoint of special or additional
properties due to their organic origin. It is because of these
additional traits or properties that wood and other organic
materials are more complex and variable than inorganic materials.

SPECIAL PROPERTIES OF WOODS DUE TO THEIR ORGANIC

ORIGIN

Cellular structure, inflammability at ordinary temperatures,
and the qualities that attract and nourish micro-organisms have
no counterparts among the inorganic materials. For example,
wood and other organic materials as a class take fire readily
under ordinary conditions and often liberate volumes of inflam-
mable gases by means of which fires are spread, whereas stones
and metal do not. Also the rotting of wood is due to the activi-
ties of bacteria which do not attack inorganic materials.

Besides these there are other characteristics, less definite
but of at least equal importance. It is the result of "life" or
physiological processes upon the chemical composition and
physical properties of .woods and other organic materials, that
causes these materials to be so variable. Not only do chemical
and physical properties of woods vary with species, but they also
vary with the age and health of individual trees from which the
pieces are cut.

CHEMICAL COMPOSITION OF WOODS

From the standpoint of chemistry also, woods are complex
and variable. Outer or living portions of a tree trunk contain

233

234 ORGANIC STRUCTURAL MATERIALS

nitrogeneous food-materials and others, such as starches and
sugars; while the inner parts, in which life-processes have
ceased, contain other substances. The chemical composition of
wood cut from young trees differs to some extent from the
chemical composition of wood cut from older trees. Variations
are also due to species. Chemical Elements, Organic Com-
pounds, and Inorganic Compounds must all be noted.

Chemical Elements. — Wood is composed principally of carbon,
oxygen, hydrogen, nitrogen, potassium, calcium, magnesium,
phosphorous, and sulphur. The relative qualities are much in
the order named. The greater part of all wood is made up of
carbon and oxygen. These elements with hydrogen constitute
about ninety-seven per cent, of dry wood.1

Ordinary woods contain about 25 per cent, by weight of water. The
remainder of 100 pounds of such wood, that is 75 pounds, contains about
37 pounds of carbon, 32 pounds of oxygen, 4 pounds of hydrogen, and
2 pounds of the other elements together. None of the elements noted
above are taken up by the tree in the form or combination in which
.they are eventually assimilated. Carbon, hydrogen, and oxygen are
obtained jointly from carbon dioxide and water. Nitrogen is absorbed
in the form of nitrate and to a limited extent as ammonia; while potash,
calcium, magnesium, phosphorus, and sulphur are taken up in the
mineral form.2

Organic Compounds. — Wood-substances must be distinguished
from the secretions that permeate them. The cells, of which all
woods are composed, are made up as follows: (1) The walls of
the cells include bundles of a definite substance known as cellu-
lose. (2) The bundles of cellulose are embedded in materials
known collectively as lignin. (3) The cells normally contain
such substances as water, protoplasm, gums, resins, tannin,
etc., etc.

Cellulose. — This is the substance of which the walls of all
plant-cells are commonly composed. Flax fiber and cotton wool
are almost pure cellulose. The chemical formula for cellulose,
which is C6HioO5 or, better still (C6Hi0O5)n, is the same as that
of starch, but cellulose differs from starch in that it resists
alcoholic fermentation. Plants themselves, however, and the

1 Wood dried at about 300°F. contains about 49 per cent, of carbon, about
44 per cent, of oxygen, about 4 per cent, of hydrogen and about 3 per cent, of
the other elements noted. See also "Timber," Roth (United States Division
of Forestry, Bulletin No. 10, p. 51), etc.

2 See also "Outlines of Botany," Leavitt, pp. 229-239.

CHEMICAL COMPOSITION OF WOODS 235

fungi that cause decay are both able to convert cellulose into
starch and then change the starch into the various forms of
sugar.1

Lignin. — At first the cells are soft and delicate, but eventually
the cell-walls become tough and woody and the protoplasm
disappears. These changes are due to the appearance of the
lignin and the process is known as lignification.

Lignin is harder and more elastic than cellulose. It forms
the characteristic part of the woody-cell and a large part by
weight of ordinary wood.2 The chemical composition has not
been satisfactorily established, but is variously given as Ci8H2oO8
and CigHigOs. Lignin differs from cellulose principally in its
proportion of carbon.

It is not known whether the composition of lignin is the same
in all woods. The difference between hardwoods and softwoods
seems to bear some relation to differences in proportions of
cellulose and lignin rather than to differences in the composition
of these compounds. As a general rule the harder the wood the
larger is the proportion of lignin.

Associated Materials. — Chemical differences due to species are
influenced less by the differences that exist in the walls of the
cell-structures than by the differences that exist in the composi-
tion of the materials that are contained in, or are associated with,
the cell-structures. The composition of the walls is fairly con-
stant for all species, but the composition of the numerous gums,
resins, tannin, and other associated materials is not constant.3

Sap. — This is as necessary to plant life as blood is to animal life.
The ascending, or " crude" sap, contains various minerals and nitroge-
nous nutriment derived principally from the soil, while the descending,
or- " elaborated " sap, contains the more complex organic preparations
that have been completed in the foliage through the instrumentality of
the chlorophyll. The influence of sap on decay is considerable. In
the sap are sugary and other substances that attract and foster the
microorganisms that cause decay. It is the presence of watery sap
that makes necessary the curative processes included under the term
" seasoning."

l" Timber," Roth (United States Forestry Division, Bulletin No. 10,
p. 51).

2 Lignin is contained in and forms the characteristic part of bast-cells.

3 See also " Microchemistry of Plant Products" Stevens ("Plant Anat-
omy," pp. 330-367); United States Dispensatory; etc.

236 ORGANIC STRUCTURAL MATERIALS

Protoplasm. — The viscid semi-fluid substance that exists within young
cells contains carbon, hydrogen, oxygen, and nitrogen, with traces of
sulphur, phosphorus, etc. This is the substance in which all plant-
structures originate. The name is from the Greek protos (first) and
plasma (formed matter).1

"The albuminous substances which compose protoplasm differ from
the carbohydrates produced by assimilation, in containing a consider-
able proportion of nitrogen often with some sulphur and phosphorus.
It is in the formation of these nitrogenous, or albuminous, matters that
the nutrient mineral salts are put to use. Where this final step in the
production of proteid matter is taken is not definitely known. It may
be that it is in the green tissue of the leaf, or it may be at all growing
points."2

Inorganic Compounds. — The mineral constituents of wood are
the parts that have been absorbed from the soil and then pre-
pared for assimilation in the foliage. Much of this mineral
matter remains in the foliage and is returned again to the soil
when the leaves fall in the autumn, so that the net loss to the soil,
caused by the tree, is inconsiderable. The quantity of mineral
matter retained in the tree is very small when compared with
the quantity of carbon that is gathered by the tree from the
atmosphere.

The principal inorganic compounds present in wood are sul-
phates, phosphates, chlorides, and silicates of potash, calcium,
and magnesium, and frequently nitrates of these latter elements.
In addition, the basic elements, particularly potash and calcium,
may be found combined with organic acids, such as citric, malic,
tartaric, and oxalic. The larger number of chemical elements
are within this group, but their total quantity is insignificant.
The quantity varies between one-half of one per cent, and five
per cent., according to soil, climate, and other factors. The
average is about three per cent.

When wood is heated, about one-fourth of its weight is given
off as water. The volatile, inflammable gases then separate
from the carbon which burns and releases the mineral matter as
ash. The principal inorganic compounds found in ash, as dis-
tinct from wood, are sulphates, carbonates, silicates, and chlo-
rides of potash, calcium and magnesium, and usually, considerable

1 "Wood," Boulger (London, Second Edition, pp. 5 and 6.).

2 Outlines of Botany," Leavitb (p. 236).

PHYSICAL PROPERTIES OF WOODS 237

quantities of free lime also. The sulphates and carbonates of
potash and calcium usually predominate.1

PHYSICAL PROPERTIES OF WOODS

It is necessary to distinguish between the physical properties
of woods and the physical properties of stones and metals. The
variations due to life processes, age, and other physiological
causes noticeable in the properties of woods, are without equiva-
lents among the properties of the inorganic materials.

The cellular structure of wood, and its influence upon physical
properties, must be constantly remembered. This influence is
due to (a) the character of the cell-elements of which wood is
composed, (6) the arrangement of the cell-elements, and (c) the
characteristics and quantities of compounds, such as water,
that are often associated with the cell-structures without being
actually part of them.

The subject will be divided as follows: (1) The physical
properties themselves will be enumerated or described. (2)
The attempts that have been made to measure these properties
as they exist in woods will be considered. (3) The changes
produced by certain agents will be noted.

DESCRIPTIONS OF PHYSICAL PROPERTIES.— The first or
qualitative part of the subject is not difficult. Some important
properties are Strength, Rigidity, Elasticity, Resilience, Hard-
ness, Ability to Hold Fastenings, Weight, Specific Gravity,
Density and Porosity, Conductivity and Resonance.

Strength. — Strength has two meanings. There is the general
meaning and the meaning as the word is used in mechanics.
In the latter case, strength refers to properties by which resistance
is offered to the application of outside forces. An outside force
is opposed by an inside resistance, and any change that may take
place in the shape of the body to which the force is applied is
referred to as a "deformation."

The five kinds of deformation commonly recognized are extension,
compression, bending, twisting, and shearing. Extension and compres-
sion are results of direct forces acting parallel to the axis of the specimen,
while bending and twisting are due to forces that are perpendicular to
the axis of the specimen. Shearing may occur under the application of
forces longitudinally or transversely. A deformation is said to be " elas-
—

See chapter entitled " Destruction of Wood by Burning."

238 ORGANIC STRUCTURAL MATERIALS

tic" when the body in which the deformation takes place tends to recover
its original form after the force that caused the deformation has ceased
to act.

The resistance offered to the forces that cause any or all of the forms
of deformation is known as Strength. A material is said to be strong,
or it is said to possess a certain amount of tensile strength, or a certain
amount of compressive strength as the, case may be. The term elastic
strength is used to denote the resistance that is offered to forces that
produce the greatest amount of elastic deformation. The ultimate
strength of any material is the greatest resistance that the material can
offer to any kind of deformation.

Modulus of Elasticity. — Within certain limits, a definite relation exists
between the resistance that develops in a body and the deformation

FIG. 31. — Machine for testing light wooden beams.1

that accompanies it. It happens that within these limits, the ratio
between the unit-resistance and the unit-deformation in tension, is usu-
ally the same as the similar ratio in compression. This important ratio
is known as the " Modulus of Elasticity."

The Modulus of Elasticity expresses a law, first announced by Robert
Hooke in 1675, that every solid is perfectly elastic up to a certain limit
known as the elastic limit. The proportion is expressed as follows:
The elongation or compression of a specimen one inch in sectional area:
the original length of that specimen:: the weight necessary to produce the
elongation or compression: the weight that would, theoretically, produce an
elongation equal to the original length of the specimen; or
The Modulus of Elasticity =

Load per unit of cross-section

E

Elongation or compression per unit of length

1 Tinius Olsen, Philadelphia, Pa.

PHYSICAL PROPERTIES OF WOODS 239

PI

or E = — - in which E = The Modulus of Elasticity in pounds per square
Ae

inch, P = the total load in pounds, I = the length in inches, A = the
area of cross-section in square inches, and e = the elongation in inches.

The meaning of The Modulus of Elasticity may also be expressed by
the statement that it is the weight or force that would elongate a speci-
men of unit-area to twice its original length, if the specimen remained
perfectly elastic.

The Modulus of Elasticity of any material is determined experimen-
tally with the aid of machines prepared for that purpose. Typical speci-
mens are selected, measured and then subjected to loads sufficient to
cause deformations. The loads and deformations are measured and the
moduli are found by proportion as above.

FIG. 32. — Machine for testing heavy wooden beams.1

Modulus of Rupture. — This is another measure of primary importance.
This modulus for tension, compression, or shear, is the load that will
rupture a bar of unit-section of the material in question. In other
words, it is the maximum unit-stress sustained by the material just
before rupture, or
Modulus of Rupture =

Maximum load in pounds

l\i = • — •

Cross-sectional area of specimen in square inches

Rigidity. — There is the general meaning, and the definition
as the word is sometimes used in mechanics and engineering.

General Meaning. — Rigidity is here the opposite of flexibility. A
rigid body is one that is tense or stiff. Such a body is not easily de-
formed. From this point of view, rigidity and stiffness are the same.

1 Tinius Olsen, Philadelphia, Pa.

240

ORGANIC STRUCTURAL MATERIALS

Engineering Definition. — Rigidity is the property by which a body
resists change of form when acted upon by an external force; the amount
of force and the nature of the deformation are not regarded. The form
of a perfectly rigid body could not be changed by the application of an
external force, but a perfectly rigid body does not exist. The distinction
between rigidity and stiffness as these terms are used in mechanics,
should be noted. From this point of view, rigidity is the property by
which a body resists deformation, regardless of the nature of the de-
formation; while stiffness is the property by which a body resists elastic
deformation.

FIG. 33. — Olsen machine for making tortion tests.

Elasticity. — Elasticity has a popular meaning, a general mean-
ing, and a meaning as the word is used in physics, engineering,
and mechanics.

Popular Meaning. — The term elasticity is often used to denote the
property by which a body sustains a large amount of deformation and
regains its original form after the force that caused the deformation has
been removed. Indiarubber is a very elastic material from this point
of view.

"General Meaning. — Elasticity is the property by which a material
tends to resume its original form after the forces that caused it to leave
the original form have ceased to act. The difference between this defi-
nition and the one that precedes it lies in the fact that in the present
case the amount of the deformation is not material.

Meaning in Physics. — A body is said to be perfectly elastic when the
work done in producing a deformation in the body equals the work done

PHYSICAL PROPERTIES OF WOODS 241

when the body recovers its original form. A perfectly elastic body does
not exist. There is always some motion between adjacent particles
whenever a material suffers deformation and this causes friction and loss
of work. Ivory is more elastic than Indiarubber from this point of
view.

Meaning in Engineering. — The material of which a body is composed
is said to be perfectly elastic for all forces equal to or less than a certain
applied force, when the body having been deformed by that force suc-
ceeds in recovering its original form after the force has ceased to act.

Resilience. — This property is intimately connected with
elasticity. The name resilience has several meanings, as springi-
ness, the power of springing back, and the power of resuming a
former shape. Resilience also stands for the amount of work
accomplished by a body when recovering from a deformation.

Johnson1 defines resilience as "the springing back of a deformed body
after the deforming force has been removed. As used in mechanics,
however, it is the work done by the body in this springing back, which
is the same as the work done on the body in deforming it, so long as
this is inside the elastic limits. Beyond the elastic limit, the work of
deformation always exceeds the work given back by the body. The
body then does not fully recover its initial position, shape or dimensions.
Sometimes the work of deformation, whether inside or beyond the elastic
limit, is spoken of as the resilience, but this is improper. The resilience
proper is the amount of work or energy in foot-pounds, which can be stored
in an elastic body up to a given stress per square inch, and which can be
given out again by the body as useful work, if desired."

Hardness. — This is the property by which a material resists
indentation and abrasion. Hardness is influenced by density
and weight. Lignumvitse, greenheart, osage orange, and some
of the eucalypts are very hard woods. Poplar and white cedar
are soft woods.

Resistance to abrasion has been determined by pressing blocks of
wood against revolving discs covered with sandpaper. The amounts
worn from the ends of the blocks have been taken as measures of the
hardness of the specimens. The proper abrasive, the speed of the disc,
the pressure and other details are important. Indentation testing ma-
chines are also used. Tests to determine the hardness of commercial
woods have been begun by the United States Department of Agriculture.

1 "Materials of Construction," p. 75, 1908 edition.

242

ORGANIC STRUCTURAL MATERIALS

Ability to Hold Fastenings. — This characteristic property con-
tributes very largely to the usefulness of wood as a material of
construction and may also be a measure of durability, as is shown
in the case of railway ties which often fail because they cannot
hold spikes. The spikes are driven so many times that the
ends of otherwise good ties become cut and useless.1

FIG. 34. — Displacement caused FIG. 35. — Displacement caused
by common spike. Photograph, by screw spike. Photograph,
Spencer Otis Company. • Spencer Otis Company.

The ability to hold fastenings is due principally to friction; in some
cases, although to a less extent, it may also be due to adhesion.

Nails cut, break, bend, and compress the fibers of the pieces into
which they are driven. The mutilated fiber-extremities react and pre-
sent roughened surfaces that press upon the surfaces of the nails. Pres-
sure is also exerted by the fibers that have been bent and forced aside.

The forces required to withdraw nails bear some resemblance to those
required to drive them and vary with the character of the nails, the
character of the wood, and the direction of penetration. (1) It is

1 European engineers sometimes use wooden dowels that are screwed into
spaces cut for them in the ties. The spikes are driven into the dowels and
the dowels are replaced when they become cut so that they cannot longer
hold the spikes. (See United States Forest Division, Bulletin No. 50, p. 64).

PHYSICAL PROPERTIES OF WOODS 243

harder to drive and withdraw rough, blunt nails than to drive and
withdraw nails that are smooth and sharp. (2) Hard woods like oak
offer greater resistance to penetration and withdrawal than softer woods
like poplar. (3) It is easier to drive nails with the grain than across it,
and it is easier to draw nails that have been driven with the grain than
to draw those that have been driven across the grain.

A series of experiments upon The Holding Power of Railroad Spikes,
conducted at the University of Illinois,1 indicates as follows:

1. The maximum resistance to direct pull varies from 6,000 pounds
to 14,000 pounds for screw spikes, from 3,000 pounds to 8,000 pounds
for ordinary spikes when driven into untreated timbers, and from 4,000
pounds to 9,000 pounds for ordinary spikes when driven into treated
timbers.

2. The direct pull required to withdraw ordinary spikes ^ inch varies
from 2,000 to 3,000 pounds for untreated timbers, and from 2,500 to
3,500 pounds for treated timbers.

3. The direct pull required to withdraw ordinary spikes Y± inch varies
from 3,000 to 5,400 pounds for untreated timbers and from 3,800 to
5,900 pounds for treated timbers.

4. Timbers having loose fiber-structures have lower resistances to
direct pull than timbers having compact fiber-structures.

5. The amount of withdrawal which must occur for ordinary spikes
to develop the maximum resistance is less for soft woods than for hard
woods.

6. Spikes driven into treated timbers offer a greater resistance to
direct pull than spikes in untreated timbers, and the difference between
this resistance for treated and untreated timbers is greater for soft
woods than for hard woods.

7. The difference in the resistance to direct pull for the different sized
spikes in use (%6 inch, i%2 inch, and % inch) is very small.

8. The resistance of ordinary spikes to direct pull varies directly as
the depth of penetration, neglecting the tapering point.

9. Blunt-pointed and bevel-pointed spikes have a slightly greater re-
sistance to direct pull than chisel-pointed spikes.

10. For withdrawals less than y± inch, ordinary spikes which are
driven into bored holes have a little greater resistance to direct pull
than spikes driven in the ordinary way.

1 University of Illinois Bulletin, Vol. Ill, No. 18, Webber.

See also "Substitution of Metal for Wood in Railroad Ties," Tratman
(United States Forestry Division, Bulletin No. 4, 1890); "Crosstie Forms
and Rail Fastenings with Special Reference to Treated Timbers," von
Schrenk (United States Forestry Bureau, Bulletin No. 50, 1904); "Holding
Force of Railroad Spikes in Wooden Ties," Hatt (United States Forest
Service, Circular No. 46, 1906).

244

ORGANIC STRUCTURAL MATERIALS

11. The resistance to direct pull for re-driven spikes is from 60 to 80
per cent, of the resistance of newly driven spikes.

12. The efficiency of screw spikes to resist withdrawal is nearly twice
as great as that of common spikes.

13. The resistance of %-inch spikes to lateral displacement is slightly
greater than that of %6-inch spikes.

14. The resistance to lateral displacement increases with the depth
of penetration, but the increase is negligible for depths of penetration
greater than 4 inches.

15. Screw spikes are more efficient than ordinary spikes in resisting
lateral displacement.

!f£~£

• • -••••>• • - ,;fj

FIG. 36. — Metal tie plate.
Photograph, Spencer Otis
Company.

FIG. 37. — Rail resting on tie plate. Pho-
tograph, Spencer Otis Company.

Weight, Specific Gravity, Density. — The weight of a body is
the downward or specific force of that body. The specific
gravity of a piece of wood is the ratio of the weight of a given
bulk of that wood to the weight of an equal bulk of water.
Density and weight may be interchangeable.

The wood tissues in the cell-walls of all species weigh about
the same ; but the woods themselves vary considerably. Similar
volumes of woods of different species contain more or less cell-
wall tissue as the case may be. The greater the proportion of
cell walls and the smaller the proportion of air spaces, the
greater the density, and therefore the weight of the wood. Den-

PHYSICAL PROPERTIES OF WOODS 245

sity and weight may thus be indications of hardness and strength.
On the other hand, the smaller the proportion of cell-wall mate-
rial and the larger the proportion of air spaces, the smaller the
density, the weight, and the strength of the wood. Light woods
are porous and buoyant.1

FIG. 38. — Turner impact testing machine.

Not only does the weight of wood depend upon the character and
quantity of the woody tissue, but it also depends upon the water, gums,
resins, and other substances that may be associated with the woody
tissues. The principal weight variations observed in woods are due to

1 See index, "Density Test."

246 ORGANIC STRUCTURAL MATERIALS

the presence of water. Half of the weight of live sapwood may be made
up in this way. There is less water in heartwood, and more in young
and vigorous trees than in those that are older and less healthy. All
trees contain more sap at some seasons of the year than at others.
Woods that are apparently dry contain some water. The influence of
water is so important as to warrant further attention.1

As indicated, the weight of dry and clean wood is normally a sign of
strength. A heavy piece of oak is usually stronger than a lighter piece;
and, unless the extra weight is due to abnormal quantities of resin, a
heavy piece of yellow pine is stronger than a piece that weighs less.

It will be remembered that the quantity of water contained in a piece
of wood will vary with the proportions of sapwood and heartwood, and
with the state of the weather. The proportion of water in wood is usu-
ally greater than in the surrounding air. The quantity is not constant,
but, varying with humidity, amounts to about twelve per cent, of the
weight of the dry wood. The weight of wood is usually calculated from
small, sound specimens, which have been dried in a kiln at a tempera-
ture of 100 degrees C. until they reach a weight that does not vary.

The comparative weights in pounds per cubic foot of some
broadleaf woods are as follows :

Balsa Ochroma lagopus 7

Cork (from cork oak) Quercus cuber 14

Missouri corkwood Leitneria floridana 18

White Pine Pinus strobus 24

Catalpa Calalpa speciosa 25

Cypress Taxodium distichum 29

Douglas Fir. . Pseudotsuga mucronata 32

Sycamore Platanus occidentalis 35

Longleaf pine Pinus palustris 38

Maple Acer saccharum 43 .

Locust Robinia pseudacacia 45

Mahogany Swietenia mahagoni 45

Red Oak Quercus rubra 45

White Oak Quercus alba 50

Hickory Carya alba 51

Live oak Quercus virginiana 59

Ironbark Eucalyptus leucoxylon 70

Lignumvitae Guajacum sanctum 71

Greenheart Nectandra rodioei 72

Ebony Diospyros ebenum 73

^ee index, under "Moisture." See also Roth, United States Forestry
Division, Bulletin No. 10.

PHYSICAL PROPERTIES OF WOODS 247

Porosity, Penetrability. — A porous substance is one that can be
penetrated by another substance. It is one that is pervious or
full of pores. Weight and density are both influenced by
porosity.

The porosity of wood depends upon the character and arrange-
ment of the cell-elements of which it is composed, and also upon
the characteristics and quantities of foreign materials that may
be present, such as water and resin; and, since the content of water
may vary, permeability may vary also.

Heavy, dense woods are much less permeable than are light,
loose-structured woods; while clean and seasoned woods are more
permeable than woods that are resinous or green. Sapwood is
more permeable than heartwood. A study of the porosity of
woods is closely associated with a microscopic study of their
cellular structure.1 The permeability of wood has an important
bearing upon its response when treated with solutions designed
to prevent decay.

A series of experiments conducted to determine facts with
regard to the permeability of woods resulted in the statements
that follow:2

1. "All woods in the fresh, green state are impenetrable to gases even
under high pressures, except through the open vessels in the angiosperms3
and the resin-ducts in the conifers where these are not clogged by tyloses
or resin. The same is true as regards liquids, except that water solu-
tions may gradually seep through the membranes. Since it is the wood-
fibers and the tracheids which form the main part of the structure of
wood, impregnation of the vessels or resin-ducts would be of little or no
value of itself in preservative treatment. The above is due to the fact
that every cell is a closed vessel completely surrounded by its primary
wall.

2. Whenever wood seasons (beyond its fiber saturation point),
whether naturally or by artificial means, narrow microscopical slits
occur in the walls of the fibers and tracheids which render them pene-
trable to gases and liquids. These slits do not re-unite when the wood is
re-soaked although they may close up somewhat. The greater the de-
gree of dryness, the more penetrable the wood becomes.

3. Steaming green wood produces a somewhat similar effect but to a

1 American Railway Engineering Association, Bulletin No. 107, January,
1909.

2 American Railway Engineering Association, Bulletin No. 120, February,
1910.

3 Woods from Broadleaf trees.

248 ORGANIC STRUCTURAL MATERIALS

less degree unless the wood be subsequently dried also. The reason
then, that absolutely green wood cannot be successfully treated with
preservatives is due, not so much to the fact that the wood contains
water, but because the cell-walls are unbroken and therefore impene-
trable. Just what pressure these walls would resist it is impossible to
state, but it seems probable that it would run into the thousands of
pounds per square inch."

The influence exerted by tyloses upon porosity is very marked.
These obstructions, which exist in the large vessels of a number
of the broadleaf woods and in the resin-ducts of some of the needle-
leaf conifers, and, which are often visible to the unaided eye,
tend to block up the passages through which foreign fluids, such
as antiseptics, are otherwise largely introduced. Weiss separates
some of the broadleaf woods into three groups, depending upon
the presence or absence of tyloses, as follows:1

Tyloses Absent. The maples, birches, blue beech, flowering dogwood,
holly, silverbell, black and water gums, black and red cherry, basswood,
persimmon, honey locust.

Tyloses Few. Yellow buckeye, beech, red gum (sap), yellow poplar,
magnolias, sycamore, black cottonwood, eucalyptus (blue gum), white
and Oregon ashes, and the elms.

Tyloses Abundant. Large tooth aspen, hardy catalpa, desert willow,
green, pumpkin and blue ash, mocker nut, water pignut, shellbark,
bitternut, nutmeg and shagbark hickories, butternut, black walnut, red
mulberry, blackjack, white, Garry, overcup, valley, bur, cow, post and
swamp white oaks, black locust, and osage orange.

Cleavability. — When applied to wood this term denotes the
ease with which the longitudinal fabric of the wood can be
separated. The cleavability of wood is opposed by cohesion and
by some phases of the cellular structure of the wood. Cleava-
bility is influenced by temperature. It is less when it is extremely
cold.

Conductivity. — This is the property by which heat, electricity,
and sound are transmitted or conveyed. It is well known that
wood is a poor conductor of heat and a good conductor of sound,
particularly in the direction of the length of the pieces.

Dry wood is an almost perfect non-conductor of electricity,
but green or wet wood presents a comparatively low resistance
to the passage of electricity. The results of experiments con-

examinations by Eloise Gerry, United States Forest Products
Laboratory.

PHYSICAL PROPERTIES OF WOODS 249

ducted to determine the electrical resistance of woods treated
with zinc and other preservatives are as follows:1

1. The resistance of timber varies directly with the length and in-
versely with the cross-section.

2. The resistance varies almost inversely with the amount of moisture
present, between the limits of 15 and 50 per cent.

3. The resistance is lowest when measured along the grain, and highest
when measured tangentially to the growth-rings.

4. When treated with a soluble salt such as zinc-chloride, the resist-
ance varies approximately inversely as the amount of the salt present.

5. Treatment with such a soluble salt does not change the behavior
of the resistance with respect to the percentage of moisture present.
Only the amount of the resistance is changed.

6. The resistance of timber varies almost inversely with the tempera-
tare between the limits of zero and 50 degrees C.

7. The resistance of non-porous woods, such as the pines, is higher
than that of porous woods, such as the oaks and red gum.

8. Treatment of timber by different creosote processes does not
greatly change the natural resistance of the timber.

9. The conductivity of wood is due primarily to the presence in the
pores of an electrolyte formed by an aqueous solution of the salts found
in the natural timber, or of these salts and others artificially introduced.

Conductivity is diminished by porosity and increased by
density and by water. It is less when the wood is diseased.

Resonance. — Strictly speaking, resonance is the property by
which sound is repeated or sustained. Occurrences in other
branches of physics, as electricity, are similar to those in acous-
tics and have warranted an extension of the term to include cases
in which sound plays no part. Hering expresses the wider mean-
ing of the term resonance as follows:

"If any rhythmic action in one body excites rhythmic action of like
periodicity in another, whether in connection with the first body or
apparently separated from it, the second body is said to be in resonance
with the first."

The meaning of "resonance" is limited to the acoustic property
when the word is used in connection with wood.

Pores, pith-rays, and other irregularities that occur in broad-
leaf woods, interfere with the resonance of such woods and for
this reason broadleaf woods are commonly less resonant than are

1 "The Electrical Resistance of Timber," Butterfield, Engineering News,
April 6, 1911.

250 ORGANIC STRUCTURAL MATERIALS

some of those of the coniferous series. All woods are more reso-
nant when they are dry. Spruce is one of the most resonant of
woods and is used for sounding boards in pianos and violins.

"If a log or scantling is struck with the axe or hammer, a sound is
emitted which varies in pitch and character with the shape and size of
the stick, and also with the kind and condition of wood. Not only can
sound be produced by a direct blow, but a thin board may be set vibra-
ting and be made to give a tone by merely producing a suitable tone in
its vicinity. The vibrations of the air, caused by the motion of the
strings of the piano, communicate themselves to the board, which vi-
brates in the same intervals as the string and re -enforces the note. The
note which a given piece of wood may emit varies in pitch directly with
the elasticity, and indirectly with the weight, of the wood. The ability
of a properly shaped sounding board to respond freely to all the notes
within the range of an instrument, as well as to reflect the character of
the notes thus emitted (i.e., whether melodious or not), depends, first,
on the structure of the wood and next on the uniformity of the same
throughout the board. In the manufacture of musical instruments all
wood containing defects, knots, cross grain, resinous tracts, alternations
of wide and narrow rings, and all wood in which summer and spring
wood are strongly contrasted in structure and variable in their propor-
tions, is rejected, and only radial sections (quarter-sawed, or split) of
wood of uniform structure and growth are used.

"The irregularity in structure, due to the presence of relatively large
pores and pith-rays, excludes almost all our broadleaved woods from
such use, while the number of eligible woods among conifers is limited
by the necessity of combining sufficient strength with uniformity in
structure, absence of too pronounced bands of summer wood, and rela-
tive freedom from resin. <

"Spruce is the favored resonance wood; it is used for sounding boards
both in pianos and violins, while for the resistant back and sides of the
latter, the highly elastic hard maple is used. Preferably resonance wood
is not bent to assume the final form; the belly of the violin is shaped from
a thicker piece, so that every fiber is in the original as nearly unstrained
condition as possible, and therefore free to vibrate. All wood for musical
instruments is, of course, well seasoned, the final drying in kiln or warm
room being preceded by careful seasoning at ordinary temperatures
often for as many as seven years or more. The improvement of violins,
not by age but by long usage, is probably due, not only to the adjust-
ment of the numerous component parts to each other, but also to a
change in the wood itself, years of vibrating enabling any given part
to vibrate much more readily."1

*" Timber," Roth (United States Division Forestry, Bulletin No. 10,
pp. 24, 25).

PHYSICAL PROPERTIES OF WOODS 251

Hygroscopicity. — This is the property by which dry wood
absorbs water from the air, loses it when dried again, and then
gathers new supplies when the wood is re-exposed. Hygro-
scopicity diminishes the value of wood, since variations in mois-
ture are accompanied by changes in volume. A door will stick
during the summer when outdoor air has free access to the house,
but will loosen during the winter when the windows are closed
and the house is heated. Contraction and expansion may be
repeated so many times as to interfere with strength. A piece of
wood affected in this manner has not decayed but rather may be
said to have aged. The tendency is greatly reduced when wood-
work is protected with oils, paints, and varnishes.

Color. — Color is a physical property. This is so regardless of
the chemical means by which it is brought about. The color of
wood, which is due to the presence of pigments manufactured by
the tree during its lifetime, differs with species, and is more or less
characteristic of them, so that it may be of considerable assist-
ance in identifying woods.

In practically every species the wood first formed is almost colorless.
But later, as the wood changes from sapwood to heartwood, the char-
acteristic pigments appear in the heartwood. Tints frequently vary as
woods are cut from younger or older trees. When woods are exposed
to the weather, chemical changes take place in the pigments, which then
become darker. Prolonged immersion in water also causes woods to
become darker. Some pigments are of such a character that they can be
removed when the woods in which they were formed are soaked in
water, and many pigments removed in this manner are used as dyes.
Disease, such as " bluing," may cause colors in woods.1

Color may or may not be desirable. One of the factors that causes
many woods to be preferred in indoor finish is color; and, where natural
color is lacking, it is often obtained artificially by means of stains.
Color is not desirable in spokes, handles, and wood used for paper pulp.

MEASUREMENTS OF PHYSICAL PROPERTIES.— This

second part of the subject is more difficult than the first. It is
easy to describe qualities as such, but it is not as easy to measure
such qualities serviceably where the material is as variable as
the one in question.

Not only do wood-specimens cut from trees of the same species

1 See also "The 'Bluing' and the 'Red Rot' of the Western Yellow Pine,"
von Schrenk (United States Bureau of Plant Industry, Bulletin No. 36,
1903).

252 ORGANIC STRUCTURAL MATERIALS

vary with age, soil, and environment, but pieces cut from the same
tree vary with water, imperfections, and proportions of sapwood
and heartwood. Moreover, the properties of the same piece of
wood may vary from day to day as the result of ordinary change?
in the amount of moisture in the atmosphere. It is obviously
easy to measure the strength of a specimen that has once been
selected, but very difficult to secure the specimen if it is to stand
for the species as a whole.

A test designed to measure strength or any other property,
includes three parts or operations : (1) A specimen that will repre-
sent the material must be selected; (2) the specimen must be
prepared for the test, that is, it must be reduced to exact dimen-
sions; (3) the prepared specimen must be tested in a machine
designed for that purpose. The difficulty is encountered under
the first heading.

The physical properties of woods are often measured, but
comparatively few of the results obtained agree closely with one
another; variations of as much as one hundred per cent, are not
uncommon. All specimens are tested in practically the same
manner so that the discrepancies must be due to the fact that the
specimens are seldom selected and prepared upon a common basis.
Differences which existed in the properties of several specimens
of Eucalyptus wood are shown by the tables on pages 253 and 254.

The principal points upon which engineers have not agreed
when selecting and preparing test-specimens of wood relate to
standards for moisture and sizes of test-specimens.

(1) STANDARDS FOR MOISTURE.— Wood-elements become
soft, swollen and pliable where they are wet. Seasoning expels
some of the moisture and brings a larger number of wood-
elements within a given space. The wood is then stronger and
more rigid. These matters may cause the strength of wood to
vary as much as four hundred per cent. A standard is there-
fore necessary. In tests conducted for the National Forest
Service, Professors Fernow and Johnson adopted twelve per
cent, by weight of dry wood as their standard.1

(2) SIZES OF TEST-SPECIMENS.— It is easier to select
representative samples of stones and metals than to select samples
of woods in which conditions with regard to age, grain, moisture,
imperfections and proportions of heartwood are all approximately
similar.

1 See index for "Moisture in Wood" and "Seasoning in Wood."

PHYSICAL PROPERTIES OF WOODS

253

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PHYSICAL PROPERTIES OF WOODS 255

Large Test-specimens. — It is hard to select large pieces of
wood upon a common basis. Most large pieces are individual
rather than representative and tests of such pieces yield results
for the pieces thus broken rather than results that represent the
species at large. On the other hand, tests of large pieces are
useful because they show the results of imperfections.

Small Test-specimens. — The fact that small pieces are abnor-
mally perfect causes them to yield results that are larger than
those observed in actual practice. But such pieces possess the
advantage that it is easier to select them upon a common basis.
The results of tests upon small specimens agree more nearly with
one another and are practical in that they make comparisons
possible.

Large and Small Test-specimens. — The purpose for which the
test is to be made should be considered. If the examination is
to be exhaustive, large and small pieces should both be tested.

The differences that, exist between the physical properties of
woods and the physical properties of ordinary inorganic struc-
tural materials, may be epitomized as follows :

1. Stones and metals possess physical and chemical properties, while
woods possess physical and chemical properties and also other properties
that result from physiological processes.

2. The properties that result from physiological processes cause woods
to vary. Pieces cut from the same tree differ from one another, while
the same piece may vary from day to day as water is absorbed and dis-
pelled. Changes in woods are caused by seasoning and the application
of preservatives. Stones and metals are much more homogeneous and
constant.

3. It is comparatively easy to select representative samples of stones
and metals, but it is not easy for the average experimenter to select
samples of woods upon a common basis as to moisture and imperfections.

4. Engineers have agreed to a greater extent upon specifications for
testing stones and metals, and to a less extent upon specifications for
testing woods.

5. Stones and metals are often tested by those who use them. Woods
are less often tested by those who use them. In the case of woods, the
results of tests conducted in Government or other laboratories are often
preferred when such figures are employed at all.

6. Tests of stones and metals when conducted upon a scientific basis,
give helpfully practical results. The coefficients of safety are here com-
paratively low and constant.

256 ORGANIC STRUCTURAL MATERIALS

7. Tests of woods when conducted upon a scientific basis do not give
equally practical results. The coefficients of safety are high and vari-
able. Results obtained in this way are not satisfactory criteria of the
actual working strength of the pieces.1

Two facts are emphasized: One is that the basis upon which
the sample is selected and prepared is of unusual importance in
the case of a substance as variable as wood; and the other is

FIG. 39. — Dorry machine for making abrasion tests.

that all figures obtained for woods should be used with the very
greatest caution. Such figures should never, under any con-
sideration, be used with the confidence that is warranted in con-
nection with figures obtained similarly for the more homogeneous
stones and metals.

The tests made to obtain values for the physical properties of
woods can be arranged in several groups, each one depending

1 For discussion of factors of safety and safe working stresses for structural
timbers, see Report of Committee on Wooden Bridges and Trestles, American
Railway Engineering Association, Bulletin No. 107.

PHYSICAL PROPERTIES OF WOODS 257

primarily upon the way in which the test-specimens were
selected. These groups are as follows:

1. Many experiments have been performed from time to time
that have not been characterized by any particular method or
principle such as underlie the investigations that will be described
in the succeeding paragraphs. Details as to the selection of
specimens are incompletely given or are entirely lacking. The
botanical accuracy of the specimens is open to doubt in many
cases. Major attention was given to the manipulation of the
specimens in the testing machines. Properties other than
strength and weight were seldom noticed. All of the experiments
that are not alluded to in the descriptions that follow are included
in this group.

The results of the experiments included under this head differ
widely from one another, but some of them are helpful for special
reasons; for example, Laslett and Rankin's experiments were
performed principally upon foreign woods.

2. Experiments were conducted for the Tenth United States
Census, by Sharpless, at the Watertown Massachusetts Arsenal.
Botanical accuracy was assured, but in other respects the
selection of specimens was not guided by factors that would
now be considered. So far as is known, most of the specimens
were from the butts of trees. Nothing is known of moisture
conditions save that specimens were carefully seasoned. About
twelve hundred specimens, representing over four hundred species,
were tested. This allowed only two or three tests for each species.

The series is valuable because it includes almost all American
species, and the results arrived at are often quoted. It is well to
note that part of the results of these experiments were originally
reported in the metric system. Coefficients were originally com-
puted in kilograms and millimeters, whereas weights were given
in pounds. This has led to some confusion.

These experiments are characterized as follows:

Botanical accuracy was assured.

Methods of selection were not definitely described.

Moisture conditions were not standardized as far as known.

Small specimens alone were tested.

Few tests were performed.

A large number of species was covered.

258 ORGANIC STRUCTURAL MATERIALS

These experiments were described originally in Vol. IX,
Tenth United States Census; Executive Document No. 5, Forty-
eighth Congress, First Session; Sargent's "Silva of North
America" and "Catalogue of the Jesup Collection of Woods."

3. Some experimenters, while admitting the difficulties that
have been noted, prefer to test large specimens because they are
the ones employed in practice. One important result obtained
by such experiments is the determination of the extent to which
imperfections lower strength. Experiments conducted under
this head are described in Professor Lanza's " Applied Mechanics "
and in publications noted in the succeeding sections.

4. In a series of experiments conducted for the National Forest
Service, then called the United States Division of Forestry,
Professors Fernow and Johnson acknowledged the difficulties of
selection that have been noted. Test-specimens were selected
upon a common basis as to age, moisture, proportions of heart-
wood, imperfections, and other matters, and about forty thousand
tests were made, distributed over thirty-one American species.
Both large and small test-specimens were employed.

The details considered and the methods evolved during this
study were of such a nature as to influence all subsequent efforts.
The study is disappointing, in that results were obtained for so
few species.

The series is characterized as follows :

Botanical accuracy was assured.
Soil and forest conditions were noticed.
Test-specimens were from representative portions of trees.
Representative trees were selected.

Moisture conditions were standardized at 12 per cent, of the dry
weight of the wood.

Small test-specimens and large test-specimens were used.

Studies of strength and weight were emphasized.

Many tests were made.

A small number of species was covered.

The records are complete and reliable.

These experiments were originally described in Circular No. 15
and other publications of the National Division of Forestry, in

PHYSICAL PROPERTIES OF WOODS 259

Professor J. B. Johnson's "Materials of Construction" and in
Professor Fernow's " Timber Physics," Parts 1 and 2.1

5. A series of experiments begun more recently (1902) by the
National Forest Service, is distinct from the one referred to in the
preceding articles as follows: The earlier study was character-
ized by emphasis laid upon strength and weight, while the later
study is characterized by attention paid to other properties as
well. Physical properties are studied, but, in addition to these,
there are investigations of technological processes such as kiln-
drying and the application of preservatives. The influences of
some of these processes and materials upon physical properties
have been investigated.

These tests may be grouped as follows: (1) Tests of life-sized
pieces or market products, such as bridge stringers, railway ties,
wheel spokes, and axe handles, intended to yield results upon
which grading rules, specifications, and coefficients for design
can be based. (2) Tests of smaller pieces selected upon the same
basis as to silvi-cultural conditions, age, grain, imperfections, and
moisture. The details of the tests are varied. The influence of
speed of application of load, temperature, etc., is noted. All the
conditions alluded to in the earlier part of this chapter have been
provided for in these experiments, which are second to none in
both scientific and practical importance.

These investigations, organized by Professor William Ken-
drick Hatt, have been described in the " Transactions of the
American Society of Civil Engineers," Vol. LI, 1903; in the
" Progress Report on the Strength of Structural Timber" (United
States Bureau of Forestry, Circular No. 32, 1904); in " Instruc-
tions to Engineers of Timber Tests," Hatt (United States Forest
Service, Circular No. 38, 1906); in the "Second Progress Report
on the Strength of Structural Timber," Hatt (United States
Forest Service, Circular No. 115, 1907); in "Strength Values for
Structural Timbers," Cline (United States Forest Service, Cir-
cular No. 189); and elsewhere.2

1 Publications of the National Forest Service.

2 See also report of the Committee on Wooden Bridges and Trestles of
The American Railway Engineering Association, reprinted in Engineering
News, March 25, 1909, and referred to in Engineering News, February
22, 1912, as probably the best compilation of safe values to be used for
unit stresses in structural timbers.

260 ORGANIC STRUCTURAL MATERIALS

Density Test for Grading Southern Hard Pine. — This test, which
is employed to grade the various kinds of Southern Hard Pine
timbers, is the result of a long investigation conducted by the
United States Forest Service and the American Society for
Testing Materials. The experiments showed that the strength
of Southern Hard Pine timbers depends less upon peculiarities
due to species than upon the cellular structure of individual
pieces.

Until the Density Test was suggested no standard existed by
which the quality of individual timbers could be determined
accurately. The rule, which is characterized by brevity and
simplicity, is as follows:1

DENSITY RULE FOR GRADING SOUTHERN HARD PINE

"Dense Southern yellow pine shall show on either end an average of
at least six annual rings per inch and at least one-third summer wood,
or else the greater number of the rings shall show at least one-third
summer wood, all as measured over the third, fourth and fifth inches
on a radial line from the pith. Wide-ringed material excluded by this
rule will be acceptable provided that the amount of summer wood as
above measured shall be at least one-half.

"The contrast in color between summer wood and spring wood shall
be sharp, and the summer wood shall be dark in color, except in pieces
having considerably above the minimum requirement for summer wood.

"In cases where timbers do not contain the pith and it is impossible
to locate it with any degree of accuracy, the same inspection shall be
made over 3 inches on an approximate radial line beginning at the edge
nearest the pith in timbers over 3 inches in thickness, and on the second
inch (on the piece) nearest to the pith in timbers 3 inches or less in
thickness.

"In dimension material containing the pith, but not a 5-inch radial
line, which is less than 2 by 8 inches in section or less than 8 inches in
width, that does not show over 16 square inches on the cross-section, the
inspection shall apply to the second inch from the pith. In larger mate-
rial that does not show a 5-inch radial line the inspection shall apply to
the 3 inches farthest from the pith.

"Sound Southern yellow pine shall include pieces of Southern pine
without any ring or summer-wood requirement."

Von Schrenk comments upon these rules as follows:

"While the new rule may at first sight appear to be a somewhat
radical departure from past standards, a careful study will show that

^'Yellow-Pine Timber Graded Without Guesswork," von Schrenk
(Engineering News, February 24, 1916).

PHYSICAL PROPERTIES OF WOODS 261

such is not really the case. The Density Rule, when applied to a mixed
lot of the various Southern pine timbers of the several botanical species,
will include most of the pieces of the true botanical longleaf pine in the
grade hereafter to be known as " Dense Pine;" a smaller percentage of
the denser pieces of loblolly, Cuban and shortleaf pine also will fall
within the dense grade; and on the other hand, a small percentage of
the more rapid-growing pieces of longleaf will be excluded, as will also
a great majority of pieces of loblolly, Cuban and shortleaf.

"It should be clearly understood that the classes "Dense Pine" and
the less desirable "Sound Pine" refer specifically to quality of density
when considered from the structural or strength standpoint and that
they replace the botanical terms hitherto used — longleaf, shortleaf, lob-
lolly, etc.

"It should also be clearly understood that the usual specifications
as to the percentage of heart and sap are in no way changed. In other
words, where timber for long service is demanded, together with high
strength qualities, Dense Pine should be specified with a minimum
amount of sapwood, or what is known as heart timber.

"A feature of the new rule that particularly recommends it is that it
is easy of application. For the first time there is available for classifying
structural timbers a rule which is based on actual measurement and
which has nothing to do with catch- judgment or feeling. Numerous
diagrams and illustrations in the Southern Pine Association's density
rule book show how simple is the method and how effectually disagree-
ments are eliminated."

THE WEIGHTS AND MODULI THAT APPEAR IN THIS
BOOK ARE:

First. — Those derived from experiments conducted by the National
Forest Service and placed in the "fourth group" explained above.
These figures, as far as they exist, occupy the leading spaces in
the tabulated descriptions of species under the titles "Weight,"
"Modulus of Elasticity," and "Modulus of Rupture." The spaces
set apart for these figures are left vacant for other insertions where
results under this group have not been reported.

Second. — Those derived from experiments conducted at the
Watertown Arsenal by the Tenth United States Census and placed
in the "second group" explained above. These figures appear in
the spaces that follow those set apart for the Forest Service figures
or their equivalents.1

All coefficients are in pounds per square inch; fractions of
pounds in weight and the lower figures in coefficients have been
omitted as superfluous.

1 Authorities responsible for figures other than those mentioned above
are given in connection with the figures employed.

262 ORGANIC STRUCTURAL MATERIALS

INFLUENCE OF MOISTURE, ANTISEPTICS, AND HEAT UPON THE
PHYSICAL PROPERTIES OF WOODS

MOISTURE IN WOOD.— Moisture exerts a very real effect
upon the physical properties of wood. Many of the variations
so noticeable in these properties are due to this cause. Moisture
also acts upon woods in other ways; for example, woods suffer
from micro-organisms that are assisted in their life and growth
by the presence of moisture.

It is convenient to distinguish between the kinds of moisture
that may be present within woods. The moisture may be sap,
introduced while the tree was alive. Or, the moisture may have
been introduced later after the tree was cut down, as when
finished timbers are exposed to the weather. - Other moisture
may be impure; but sap, a vital fluid necessary to the life of trees,
contains preparations that are of an organic putrefactive nature;
and these, more than other impurities, seem to attract micro-
organisms, or else assist their progress after they have once
entered the wood.

The quantity of the moisture and its distribution are both
important.

Quantity of Moisture. — One-half of the weight of live sapwood
may be water. There is less water in heartwood than in sap-
wood, and more in young and vigorous trees than in those that
are older and less healthy. All trees contain more sap at some
seasons of the year than at others; and all woods, even when
well seasoned and apparently dry, contain some water. The
porous structure of clean wood permits water to pass in and out,
so that in the same piece, the quantity of water may vary from
day to day.

Influence of Season of Cutting. — The influence which the season of
cutting exerts upon wood may be noted in this connection. The usual
preference exhibited for winter felled timber has several causes. (1) It
is thought by many that the quantity of moisture in a tree is so much
less during the winter that the quality of the wood is affected. (2)
Others prefer the winter for felling because fungi are then less active
and there is less danger of infection before the log can be cut up in the
mill. (3) Yet others regard the quality of the wood itself as better
during the winter season. (4) In the North, lumbermen prefer the

INFLUENCE OF MOISTURE ON WOODS

263

winter season for cutting because transportation problems in the forest
are then more easily met. These points will be considered separately :

First, there is fully as much sap in a tree during the winter as during
summer. Its composition may vary, but its total amount is, if anything,
greater during the winter.1 Second, it is true that fungi are less active
during the winter season and that there is
less danger of freshly cut wood becoming
infected and consequently weakened at
that time. Third, with the exception of
the outer sapwood, no real difference exists
in the quality of the trunk during the
winter and the summer. Fourth, this
point is one of convenience and has
nothing to do with the quality of the
wood.

Of the above points the second only
need be considered as a factor influencing
the quality of wood. As a matter of fact
if summer felled logs and winter felled
logs could both be immediately cut up into

lumber as soon as they were felled, and if the wood in each case could
then ^be promptly and equally seasoned by the same process the two
kinds could not be distinguished from one another.

FIG. 40. — Defects due to
unequal shrinkage.2

Distribution of Moisture. — The practical importance of this
subject will be appreciated when it is remembered that the prin-
cipal difficulty encountered by those who season woods arises
from attempts to expel moisture evenly from all parts of a piece
in which it does not exist evenly.

Distribution may be studied from the standpoint of the entire
piece, and it may be studied locally as it relates to the wood-
elements. The distribution throughout the entire piece is such
that there is more water in the sapwood than in the heart. Mois-
ture is distributed throughout the wood-elements, so that some
of it occupies the cavities in the wood-elements and some satur-
ates the walls of the wood-elements.

1 "Sap in Relation to the Properties of Wood," Record (Proc. American
Wood Preservers' Association, Baltimore, Md., 1913, pp. 160-166).

2 Acknowledgments to United States Forestry Division, Roth, Bulletin
No. 10, pp. 33 and 35.

264 ORGANIC STRUCTURAL MATERIALS

Influence of Moisture. — There are three ways in which mois-
ture influences woods: (1) moisture causes weakness and other-
wise affects the physical properties of woods; (2) moisture influ-
ences distortion; and (3) moisture is a factor in decay.

INFLUENCE OF MOISTURE ON PHYSICAL PROPERTIES
OF WOODS. — Wood-elements are swollen and pliable when
they are wet. Seasoning expels moisture and brings more of them
within a given space. The woods are then drier and stronger.
Seasoning may increase strength as much as four hundred per
cent.; and comparatively weak wood, such as pines, may be
thus rendered stronger than better woods, such as oaks, that
have not been seasoned.

The influence of moisture upon the strength of wood has been
summarized by Tiemann:1

"As the moisture of a piece of wood is reduced by drying, the strength
of the wood increases, and as moisture is re-absorbed, the strength, up
to a certain limit, is again reduced. So great, indeed, is the effect of
moisture, that under ordinary conditions it outweighs all other causes
that affect strength, with the exception, perhaps, of decided imperfec-
tions in the wood."

An .exception must be noted. It is hard to dry a large timber
that is full of knots and other irregularities without some injury
to the piece as a whole; and this injury may offset much of the
improvement that takes place otherwise through seasoning. To
prevent decay, all wood should be dry, and all wood-elements
and most timbers are stronger when they are dry; but the net
strength of a very imperfect piece may not be always greatly
increased by drying.

The Influence of Moisture upon Distortion. — The changes that
take place in the form of a piece of wood are due to the discharge
of water from the wood-elements. The fact that moisture is not
distributed evenly throughout the wood, and the further fact
that wood-elements vary in their character and arrangement are
important in this connection.

When a wood-element shrinks the principal change takes place
in its thickness, and the least change takes place in the direction
of its length; the length shrinkage of a plank can usually be prac-
tically disregarded. Wood-elements near the surface of a log

1 "Effect of Moisture Upon the Strength and Stiffness of Wood," Tiemann
(United States Forest Service, Bulletin No. 70).

PHYSICAL PROPERTIES OF WOODS

265

contain more moisture than those within; and the sides of planks
exposed to the weather may shrink differently than those pro-
tected.

Horizontal wood-elements usually shrink differently from the
vertical wood-elements that are bound
together by them. Severe strains at right
angles to one another are then developed
and the separations that take place are
known as checks. Most needle-leaf woods
shrink evenly, but it is often harder to expel
moisture from broadleaf woods, such as oaks,
that are characterized by complex fiber
arrangements without some injury.

Influence of Moisture upon Decay. — Decay
is due to the action of certain micro-organisms
that require moisture for their development,
and that cannot live when it is absent. Decay

is not inherent in woods ;

dry woods do not decay.

Decay m a y p r o c e e d Fw 4i;_Result of

when the moisture is unequal shrinkage.

rmrA Hnt ear* a« Hie The formation of
pure, out sap, as ais- checks i

tinct from pure water,

contains compounds that attract or that

add to the activity of the forms that cause

decay.2

Influence of Antiseptics and Preservative
Treatment Upon the Physical Properties
of Woods. — The phj^sical properties of
woods may be influenced by (1) the anti-
septic, and by (2) the process employed to
introduce the antiseptic.

The effect of creosote upon the physical
properties of woods is negligible or bene-
ficial. But zinc chloride and some other preservatives designed
to benefit woods in some ways may injure them in others. Not
only can a concentrated solution of zinc chloride injure tissues
with which it comes into contact, but the timber as a whole may

1 Acknowledgments to Roth (United States Division Forestry Bulletin
No. 10, p. 34).

1 See index, " Fungi," "Fungus Diseases of Woods," etc., etc.

FIG. 42. — The rela-
tion of horizontal
wood-elements to verti-
cal wood-elements. 6,
a are vertical wood-ele-
ments, while c, d are
cells of a pith-ray.1

266 ORGANIC STRUCTURAL MATERIALS

be weakened by the addition of water. Otherwise, experiments
indicate that the presence of zinc chloride will not weaken woods
subjected to static loading, although the indications are that
pieces that have been subjected to zinc chloride treatment become
brittle under impact.1

As distinct from the preservative, a process may be harmful
whenever excessively high temperatures are employed. If an
appropriate process is selected, and if proper care is observed
while it is being applied, the wood will not suffer.

Influence of Heat upon Physical Properties.2 — Dry heat must
be distinguished from wet heat. Dry heat much in excess of
212 degrees expels some of the volatile products of the wood and
the wood then becomes correspondingly weak and brittle. The
equivalent of moist heat is not known. Up to a certain point
high heat, either in steam or in dry air, produced the following
results upon wood:

"(1) It permanently reduces the moisture content below that of
ordinary air-dried wood when again exposed to the air, at the same time
rendering it less hygroscopic, so that it is less susceptible to changes in
the humidity of the air; (2) the moisture condition of the fiber-saturation
point is changed, being reduced by high temperatures with dry air or
superheated steam; (3) the strength of the wood is increased, except in
the resoaked condition."

Woods deteriorate, or fail, from use, exposure, age, decay, fire,
marine life, and land life; and they are defended more or less
successfully by seasoning, internal treatment, and external treat-
ment. These subjects will be treated separately in the chapters
that follow.

1 "Experiments on the Strength of Treated Timber," Hatt (United States
Forest Service, Circular No. 39, p. 21); "Crosstie Forms and Rail Fastenings
with Special Reference to Treated Timbers," von Schrenk (United States
Bureau of Forestry, Bulletin No. 50); "A Primer of Wood Preservation,"
Sherfesee (United States Forest Service, Circular No. 139, p. 9); see also
chapter entitled "Preservatives Applied within Woods," etc.

2 See index, "Failure of Wood Because of Fire."

CHAPTER X

FAILURE OF WOOD BECAUSE OF USE, EXPOSURE, AGE, AND

DECAY

The changes that take place as a result of use, exposure, and
age, are distinct from those that take place as a result of disease.
Changes due to the former causes are of a mechanical nature; the
wood-elements remain healthy but they separate more easily
from one another. The changes due to decay are of a chemical
nature; disease causes wood to break up into other compounds.

FAILURE DUE TO USE. — The mechanical deterioration of
wood is influenced by the way in which it is used. Flooring is
worn by abrasion. The life of a railway tie may be measured, by
the speed, weight, and volume of traffic that passes on the rails
above. Ability to hold fastenings is a factor in the life of wood
when in some positions. Thus wood may wear out before it
rots. Deterioration due to use is opposed by physical proper-
ties such as strength, hardness, rigidity, and weight.

FAILURE DUE TO EXPOSURE. — Woods may deteriorate as
the result of simple exposure to the weather. Expansion and
contraction due to extremes of temperature and the presence or
absence of water cause wood-elements to loosen from one another.
Deterioration takes place more gradually when woods are pro-
tected from the weather. Wooden roof-trusses in European
churches have remained good during many centuries.

FAILURE DUE TO AGE.— Woods " age" much more rapidly
when out of doors. Old wood becomes brittle and is then known
as "brashwood." In a living tree age seldom acts alone, but, by
lowering the vitality of the tree, makes it possible for disease to
enter where resistance has been overcome. There is probably no
such thing as the natural death of a tree in the forest and it is
equally true that woods seldom fail in construction, simply
because they are old. The vitality, soundness or resistance of
a piece of wood may be roughly estimated by twisting a shaving
of it between the fingers.

267

268 ORGANIC STRUCTURAL MATERIALS

FAILURE DUE TO DECAY. FUNGOUS DISEASES.— Trees
in the forests, and woods waiting to be used, or already in con-
structions, are susceptible to diseases that cause losses so serious
as to constitute one of the greatest drains upon the timber
resources of the world.

All wood, whether employed in railroad ties, telegraph poles,
bridge, mine or house timbers, are susceptible to the same or
similar diseases. Wooden warships once suffered more from them
than from the guns of the enemy. It is said that wooden ships
have failed after seven or eight years of service. Selection, seas-
oning, and the attention paid to protection makes it possible for
woods to last longer at the present time; yet even now woods
exposed to the weather endure for a comparatively short time,
while the premature failure of beams in protected places is not
uncommon.

Many names refer to practically the same causes of deteriora-
tion in wood. Wet-rot, dry-rot, disease, decay, mildew, soft-rot,
canker, bluing, rust, bot, dote, mould, and other terms are thus
employed. The results indicated by all of these names are due
to the presence of bacteria or fungi.

Fungi. — These non-seedbearing plants differ from ferns and
mosses, which are also non-seedbearing plants, in that the latter
require light and contain the green substance chlorophyll which
serves in the preparation of plant food; whereas the former, that
is fungi, are without chlorophyll and do not require light. Fungi
cannot draw their food from air and soil like ordinary plants and
must therefore attach themselves to appropriate substances from
which they can draw their food. Fungi are destructive rather
than constructive and in this respect resemble animals rather
than plants.

REFERENCES. — "Outlines of Botany," Leavitt; "Fungous Diseases of
Plants," Duggar; "Diseases of Economic Plants," Stevens and Hall;
"Flowerless Plants," Bennett (Gurney & Jackson, London); "Fungous
Diseases of our Forest Trees," Halstead (3rd Annual Report Penn. Dept.
of Agriculture) ; " Diseases of Trees," Hartig; "Diseases of Plants Induced by
Cryptogamic Parasites," Tubeuf and Smith; "Studies of Some Shade Tree
and Timber Destroying Fungi," Atkinson (Cornell Exper. Sta. Bulletin
No. 193); Bulletins American Railway Engineering Association; "The Dis-
covery of Cancer in Plants" (The National Geographic Magazine, Vol.
XXIV, No. 1, 1913); etc.

PLATE V. FUNGOUS DISEASES OF WOOD

FIG. A. FIG. B.

FIG. A. — Fruiting Bodies of Fungus (Fomes fomentarius) (a).
FIG. B. — Fruiting Bodies of Fungus (Daedalea quercina) (6).

FIG. C.

FIG. C. — Fruiting Body of Fungus (Lentinus lepidus) on Red Fir
Railway Tie (c).

(a) and (6) From "Diseases of Deciduous Forest Trees," von Schrenk and Spauldirig
(United States Bureau of Plant Industry, Bulletin 149). (c) From " Seasoning of Timber,"
von Schrenk (United States Bureau of Forestry, Bulletin 41).

(Facing page 268.)

USE AGE AND DECAY OF WOODS

269

Plant Life Has Been Divided in Many Ways. — The Linnsean classi-
fication separates all plants into Phanerogams, or seed-bearing plants,
and Cryptogams, or non-seedbearing plants. The Cryptogams are
again divided into one part, sometimes called the higher, which includes
the ferns and mosses; and another part, sometimes called the lower,
which includes the algae, lichens, and fungi.

The fungi are divided into saprophytes and parasites according as
they derive food from dead or living tissues. Some species are capable
of existing as both saprophytes and parasites and for this reason some
authorities (see Tubeuf and Smith, p. 3) separate fungi into true and
hemi-saprophytes and true and hemi -parasites. There are sub-divisions
in each case.

A piece of mouldy bread may
be studied in this connection with
profit. Such bread first emits a
characteristic odor, then becomes
discolored, and is eventually de-
stroyed. Minute threads of the
" mould" penetrate throughout
the mass and their extremities
eventually appear upon the sur-
face of the bread as a delicate felt
or fur. These extremities finally
swell, burst, and liberate countless
spores, some of which find a con-
genial substratum, germinate, and
produce similar results.

The swollen ends of the ex-
tremities are the "fruiting bodies"
of the fungi within the bread. In
the same way the toadstool-like FIG. 43.— Mycelial threads of
growths seen on rotting; trees or wood-destroying fungus (Nectria
°. , , ((f ... , ,. ,, cinnabarina) in maple wood.1

timbers are the fruiting bodies

of fungi that have entered such trees or timbers. Fruiting
bodies are not always easily evident, and those of some fungi
are quite obscure. An individual fungous thread or filament is
called a "hypha," while masses of the threads or "hyphse" form
what is known as "mycelium." Bread, wood, or other sub-

1 Acknowledgments to Roth (United States Division of Forestry, Bulletin
No. 10).

270 ORGANIC STRUCTURAL MATERIALS

stances that have become infected are the "hosts"1 of the fungi
that have gained entrance to them.

Fungi attack woods through the action of solvents called
"enzymes," some of which dissolve cellulose, while others dis-
solve lignin, starches, sugars, and other compounds. The re-
moval of any one of these constituents from the wood results,
ultimately, in the total destruction of the usefulness of the wood.
The general form of the diseased piece may be retained but its
properties have been affected. Some of these wood residues are
comparatively dry and brittle while others are moist, soft, and
sponge-like.

Some fungi attack live trees. Others attack dead trees,
and yet others attack woods employed in construction. Some
kinds of fungi prefer conifers and others broadleaf trees. Bark,
heartwood, and sapwood all have their enemies. Some fungi
attack many species of trees or woods, while others attack only
one or two species.

Fungi are very numerous. Many thousands of species are
in existence. The subject is not a simple one; and the majority,
who are not experts in this subject, find it more helpful to con-
sider the Jew conditions under which all fungi act than to acquaint
themselves, with the idea of identifying all of the many forms that
cause the failures so constantly observed.2

Conditions Under Which All Fungi Act. — All fungi require
moderate quantities of heat, air, and moisture for their develop-
ment. They do not do well when excessive quantities of these
agencies are present; nor do they do well when the said agencies
are completely absent.

1. Influence of Heat upon Fungi. — Growth is retarded and
fungi are sometimes completely killed by high heat, that is by
temperatures much beyond one hundred and seventy degrees.
Many fungi are killed by the process of kiln-drying, but some are
rendered inert by this process for the time being only. The
growth of fungi is also retarded by cold, that is by temperatures
much below thirty-five degrees.3 Fungi are not killed by any

1 This term is usually restricted to the living organism upon which a
parasite grows. Saprophytes grow upon a "substratum."

2 Fungi do not confine themselves to plants. " Ringworm" as seen in
man is due to a fungus parasite (Trichophyton tonsurans).

3 These temperatures are approximate. It is not necessary to go below
the freezing point to retard the growth of fungi.

USE AGE AND DECAY OF WOODS 271

degree of natural cold, no matter how extreme, but their activities
cease, or are restricted, while such low temperatures continue.

2. Influence of Air upon Fungi. — The activity of fungi is more
or less opposed by an abundance of pure air on the one hand,
and by vacuum on the other. A moderate amount of air is
necessary for their growth.

3. Influence of Moisture upon Fungi. — Wood will not decay
while it is quite dry; neither will it decay as long as it remains
saturated with water.

These facts explain why woods last better in cold climates and
on well-drained hills, and why decay goes forward more rapidly in
warm, moist climates, and in mines. A railway tie fails sooner
than a beam that is raised up from the ground because the " med-
ium" conditions of heat, air, and moisture are more nearly se-
cured in positions where ties are employed.

Fungous diseases may be considered as they attack trees in
the forest, and as they attack woods ready for, or already in,
construction.

Fungous Diseases of Trees. — These diseases are here described
for the sake of completeness, and because some of them produce
results that are evident in merchantable lumber. Some of the
fungous diseases that attack living trees are similar to the fungous
diseases that attack woods in constructions.

Trees become infected through wounds such as the borings of
insects and injuries caused by falling limbs and by pruning.
There is sometimes an intimate connection between the attacks
of insects and those, of fungi. Some insects transfer the micro-
organisms to trees mechanically. Sap as distinct from pure
water is an important agent in the growth of disease that has
once entered the tree.

The health of a tree is important. Good health increases
resistance to disease, which resistance is less where health is low-
ered, as it may be by poor soil, by lack of light, and by the attacks
of insects. Old trees succumb more easily than younger ones,
but there is probably no such thing as the natural death of a

See also " Diseases of Trees," Hartig; "Diseases of Plants Induced by
Cryptogamic Parasites," Tubeuf and Smith; "Disease of Taxodium known
as Peckiness," von Schrenk (Contribution 14, Shaw School of Botany);
"Fungus Diseases of Forest Trees," von Schrenk (United States Depart-
ment of Agriculture Year Book 1900); "Diseases of Deciduous Forest
Trees," von Schrenk (United States Bureau of Plant Industry, Bulletin
No. 149 which also contains extensive bibliography); etc.

272

ORGANIC STRUCTURAL MATERIALS

tree. To preserve health, some trees protect the raw surfaces of
wounds with their own gums or resins. Intentional wounds,
such as those caused by pruning, should be coated with tar or paint.

The fungi that attack trees may be divided as they attack the
foliage, the roots, or the trunks of the trees.

Diseases of Foliage. — Leaves that have been attacked by spot,
mildew, or rust, cannot adequately perform their duties and the
preparation of wood is correspondingly interrupted. The foliage
of the Soft Maple (Acer saccharinum) is thus subject to attack
by a fungus called Phyllosticta acericola. Chestnut foliage is
similarly victimized by the fungus Marsonia ochroleuca, and other
fungi are associated with other trees.

FIG. 44. — Section of wood cut from cypress after attack by wood-destroying
fungus (Dcedalea vorax) .

Diseases of Roots. — Certain fungi attack the roots of trees.
For example, the fungus known as the southern root rot (Ozonium
omnivorum) attacks the roots of oaks and elms, and also those
of some smaller plants as cotton. When the roots of trees are
diseased, the wood making in the trunk is correspondingly re-
tarded. Hartig states that barren places in forests are often
caused by root fungi.

Diseases of Trunks — The trunks of live trees have many
enemies. Cypress and Incense Cedar are sometimes attacked
by the fungus Dcedalea vorax that causes peculiar cavities in the
wood. The Bull Pine (Pinus ponderosa) is subject to attack by
the fungus Ceratostomella pilifera that causes the wood to become
blue. The bark of the chestnut is subject to the bark disease
(Disporthe parasitica or Endothia gyrosa var parasitica), which

USE AGE AND DECAY OF WOODS 273

eventually kills the tree. Hardy Catalpa, White Ash, and other
trees have special enemies.1

"The chestnut blight appears to confine itself to attacks upon species
of the genus Castanea. It was first recognized in 1905 in trees near
New York City but has now spread into many States and has prac-
tically killed all of the trees that have been attacked. If the trunk is
the part affected, the tree is killed perhaps in one season, but if the small
branches are attacked, the tree may survive for several years. The
spores produce running sores and the trunks or branches that have been
girdled by these sores assume a characteristic appearance. One of the
most easily detected symptoms is the growth of sprouts or " suckers"
below the girdling lesions of the trunk and branches as well as at the
base of the tree."

Fungous Diseases of Structural Wood. — The term "structural
woods" here includes woods that are ready for construction and
those that are finally in place. Life-processes have ceased in the
woods that are now referred to, which may be either seasoned or
green. The fungous enemies of such material are very numerous,
and, just as conditions were noted under which all fungi thrive
regardless of their species, so here it is more practical to note all
of the ways in which timbers are exposed and to then study the
influence that each one of these exposures exerts upon the life
of fungi.

Structural woods may be exposed in four ways. They are as
follows :

First. — Woods may be coated by paint, metal, plaster, or simi-
lar materials.

Second. — Woods may be coated, that is enclosed, by earth or
water.

Third. — Woods that have not been coated may be exposed to
the weather.

Fourth. — Woods that have not been coated may be protected
from the weather.

The "medium conditions" of heat, air, and moisture mentioned
as necessary for the development of fungi are secured in the first

^'Disease of Taxodium known as Peckiness," von Schrenk (Contribu-
tion 14, Shaw School of Botany); "Two Diseases of Red Cedar," von Schrenk
(United States Division Vegetable Physiology and Pathology, Bulletin No.
21); "Diseases of Bull Pine," von Schrenk (United States Bureau of Plant
Industry, Bulletin No. 36); "Diseases of the Hardy Catalpa" (United States
Bureau of Forestry, Bulletin No. 37) ;" Diseases of White Ash," von Schrenk
(United States Bureau of Plant Industry, Bulletin No. 32) ; etc., etc.

274 ORGANIC STRUCTURAL MATERIALS

and third exposures. Woods are comparatively safe when in
the second and fourth exposures.

First Exposure. — Paints and other impervious coatings protect
from outside conditions but are detrimental if moisture and im-
purities are within the wood when it is coated. Coatings sea)
up the moisture and impurities, and a condition known as " dry-
rot" is likely to occur. It should be noted that the name dry-
rot refers to the results of the disease. The wreckage is dry and
chalky but the fungi that caused this wreckage could not have
lived without some moisture.

The application of paint to an organic substance such as wood must
be distinguished from the application of paint to an inorganic substance
such as iron. The principles that here apply with woods resemble
those that apply when fruits or meats are placed in cans. Air-tight
coatings should not be placed around any of these organic materials
unless they have first been sterilized, cured, or otherwise prepared.

Second Exposure. — This exposure is distinct from the one
that precedes it in one vitally important particular. Paints
and metals are practically inert, while mud and water are not.
Mud and water protect from outside influences but at the same
time dilute or cleanse away such impurities as have remained
within the wood. Even green woods are safe while under water,
and not only this, but changes take place that render them more
durable after they have been removed from the water.1

Woods do not no mally decay while submerged in mud or
water. Records show that woodwork has lasted in this manner
for over a thousand years, and there is no reason why it should
ever decay while thus protected. The softening or physical
disintegration that takes place under some conditions is not
decay.

Third Exposure. — The third exposure is associated with what
is commonly known as " wet-rot." The fungi that act when
uncoated woods are exposed to the weather seem to require or
to tolerate larger quantities of moisture than those accountable
for the changes known as dry-rot.

The medium moisture conditions necessary for the growth of
fungi in this position are supplied in two ways: (1) Excessive
quantities of water may be applied intermittently as with
marine constructions that are exposed between the tides, or (2)

1 See index for "Water Seasoning."

PLATE VI. PORTION OF FLOOR BEAM AFTER ATTACK BY DRY ROT

FUNGUS

111

i .

Lifeless Condition of Wood is Shown by Detached Material at Bottom of

Picture.

(Facing page 274.)

USE AGE AND DECAY OF WOODS

275

smaller quantities of water may be present constantly as when
timbers rest upon damp soil, and when they are exposed to the
moist atmosphere of mines.

The Influence of Top Soil. — -This is so great that the expression,
" durable in contact with the soil" is often used as a measure of
the durability of wood. Surface soil is dangerous for several
reasons. It is damp, and comparatively warm, and it restricts
the air but does not cut it off entirely. Micro-organisms are
present in the soil near the surface.

The effect of contact with top-soil is shown in the case of posts
and other timbers placed upright in the ground. Decay usually
begins in the parts of these timbers that are nearest to the surface
of the ground and later extends upward and downward from the
surface as conditions permit.

The tops of posts and similar timbers resist because they are
drained and well ventilated, and the bottoms resist if they are
driven down deep enough to escape the conditions that prevail
at the surface. A beam raised a short distance from the ground
lasts longer than one lying on its surface, because, although the
space between the timber and the soil may not be more than a
few inches, it is enough to secure some drainage and ventilation.

Some woods noted for extreme durability, average durability,
and perishability when in contact with the soil, are noted below.
Weiss estimates1 that most of the woods in the first column will

Very durable woods

Durable woods

Perishable woods

Black Locust

Catalpa

Cypress

Greenheart

Lignumvitse

Mesquite

Mulberry Red

Northern White Cedar

Osage Orange

Redwood

Western Red Cedar

Chestnut
Douglas Fir
Longleaf Pine
Southern White Cedar
White Oak

Ash

Balsam

Basswood

Beech

Birch

Cottonwood

Hemlock

Loblolly Pine

Lodgepole Pine

Red Oak

Sitka Spruce

Sycamore

Tupelo

Western Yellow Pine

White Spruce

Preservation of Structural Timber," Weiss (p. 275).

276 ORGANIC STRUCTURAL MATERIALS

probably last more than twenty-five years when in contact with
the soil; that most of those in the second column will last between
ten and twenty-five years, and that most of those in the third
column will fail in less than ten years.

Fourth Exposure. — Uncoated woods do not normally decay as
long as they remain protected from the weather in dry, venti-
lated places. On the contrary, the quality of wood is likely to
improve under such conditions, for reasons that are given in the
section devoted to " Natural Seasoning." Many of the timbers
seen in the covered wooden highway bridges that were erected
in this country, in some cases more than one hundred years ago,
are yet sound. Unpainted wooden roof-trusses have lasted for
many centuries in European churches.

Evidence of Disease in Wood. — Disease becomes apparent in
many ways. Some woods discolor, others swell and soften, while
yet others become dry and brittle. Clots of hyphae sometimes
fill cracks or appear beneath the bark of logs. Thick masses of
orange, pink, or gray material often extend like giant cobwebs
between rotting timbers in mines. Piles, ties, and mudsills may
be sound without but soft and spongy within. Sometimes this
order is reversed.

Methods of Treatment. — Preventative methods are much more
valuable than curative methods. It is usually impracticable to
attempt to control disease that has once started. It is said
that acid solutions will counteract some kinds of fungi. Disease
caused by lack of ventilation can sometimes be prevented from
spreading rapidly by providing for ventilation.

Methods of Protection. — Fungous diseases are contagious and
for this reason diseased woods should usually be destroyed. The
means by which woodwork may be more or less successfully
defended against fungus diseases are as follows: (1) Selection:
Woods that have the fewest fungus enemies should be selected.

(2) Seasoning: Resistance is greatly increased by seasoning.

(3) External treatment: Paints and other coatings may be used
to shut out the micro-organisms that cause disease. (4) Inter-
nal treatment: Woods may be saturated with antiseptics. These
subjects are treated elsewhere under appropriate titles.

CHAPTER XI

FAILURE OF WOOD BECAUSE OF FIRE. WOOD AS AN AGENT IN
CONFLAGRATIONS. FIRE PROTECTION

The fact that wood is inflammable is of far-reaching impor-
tance. The direct losses caused by the burning of finished pro-
ducts and of live woods in the forests, and the indirect losses
caused by the communication of fires from burning wood to other
property cannot be estimated. A large part of the world's incre-
ment of wealth is burned up every year, and an undue proportion
of this loss occurs in the United States, where large quantities
of wood are used in construction.

Wood is a principal agent in conflagrations for the reason that
it is the only one of the primary structural materials that takes fire
at ordinary temperatures. Stones and metals may fail because
of fire, but they do not contribute directly to flames. Many
attempts have been made to use other materials in place of wood
in naval and house architecture and even the earliest of these
attempts were due to the fact that wood will burn.

REFERENCES. — "Fire Protection of Mills, " Woodbury (John Wiley &
Sons, 1895); "Contributions of Chemistry to the Methods of Preventing
and Extinguishing Conflagrations," Norton (Journal of American Chemical
Society, Vol. XVII, 1895) ; Publications of National Board of F\re Under-
writers; Publications National Fire Protection Association; Files of
Insurance Engineering; "Process of Fireproofing Wood for the Wood-
work of Warships," Hexamer (Engineering News, March 23, 1899); "A
New Investigation of the Fireproofing of Fabrics," Whipple and Fay (Part
of "The Safeguarding of Life in Theatres," Freeman, Transactions of the
American Society of Mechanical Engineers, Vol. 27, 1906); "Waste of Our
National Resources by Fire," Baker (Proceedings of Meeting called jointly
by the American Society of Civil Engineers, the American Institute of Min-
ing Engineers, the American Society of Mechanical Engineers, and the
American Institute of Electrical Engineers, published in pamphlet, 1909);
"The Enormous Fire Waste of the United States," Cochrane (Scientific
American, June 15, 1912); "Fire Prevention and Fire Protection," Freitag
(John Wiley & Sons, 1912); "The Modern Factory," Price (John Wiley
& Sons, 1914); "Tests on Inflammability of Untreated Wood and of Wood
Treated with Fire-retarding Compounds," Prince (Report on Uses of Wood,
National Fire Protection Association, 1915).

277

278

ORGANIC STRUCTURAL MATERIALS

Fire losses are greater in the United States than in any other
country. The direct losses now exceed two hundred million
dollars every year. In its relation to the building operations of
the country this is equivalent to the destruction of one house out
of about every four built.1 This loss, which is about equal to the
total value of all gold, silver, copper, and petroleum produced in
the United States in a year, and which is many times greater
than the interest on the National debt, is one of the factors in the
present high cost of living. The sum mentioned does not include
indirect losses, or losses by forest fires.

The direct fire losses in the United States for thirty-six years
(1875-1910 inclusive), as estimated by the National Board of
Fire Underwriters, were as follows :

1875
1876
1877
1878

. .. $78,102,285
. . . 64,630,600
. . . 68,265,800
64 315 900

1889. .
1890. .
1891..
1892

. $123,046,833
. 108,993,792
. 143,764,967
151 516 098

1903. . . .
1904. . . .
1905....
1906

$145,302,155
229,198,050
165,221,650
518 611 800

1879
1880
1881
1882
1883

... 77,703,700
... 74,643,400
. . . 81,280,900
. . . 84,505,024
100 149 228

1893..
1894..
1895..
1896..
1897

. 167,544,370
. 140,006,484
. 142,110,233
. 118,737,420
116 354 575

1907....
1908....
1909....
1910....

215,084,709
217,885,850
188,705,150
214,003,300

1884

110 008 611

1898

130 593 905

1885
1886
1887

. . . 102,818,796
. . . 104,924,750
120 283 055

1899..
1900. .
1901

. 153,597,830
. 160,929,805
165 817 810

Over five
direct lo
six year

billion dollars
sses in thirty-

5

1888

. . . 110,885,665

1902

161 078 040

Fire losses are increasing faster than the population of the
country is increasing, that is, the number of fires per capita is
increasing.

The indirect losses that take place as a result of fire must be
considered also. Such losses include the costs of maintaining
fire departments and water supplies for purposes of fire fighting,
excessive insurance and losses in rents and business. It is
estimated that in 1907 the total direct and indirect losses from
fire amounted to $456,485,900, a sum almost half as great as the
value of the new building constructions for that year. That is to

1 "Proceedings of the Forty-ninth Annual Meeting of the National Board
of Fire Underwriters," p. 19. Report "National Conservation Commission,
Section of Minerals," Washington, December, 1908.

WOOD AN AGENT IN CONFLAGRATIONS 279

say, during that year about one billion dollars was expended
upon new buildings and construction work, and approximately
half of this increment was destroyed by fire. Such a sum is
greater than the true value of the real property and improvements
in any one of the States of Maine, West Virginia, North Carolina,
North Dakota, Alabama, Louisiana, and Montana.1

There is also the loss of human life. According toft-he
United States Census, 6,000 persons died of burns and 10,000
persons were badly injured by the same cause during 1906.

All comparisons in connection with this subject are startling,
yet all of them are conservative. Baker estimates that the
buildings destroyed every year in the United States if placed
upon lots with an average frontage of 65 feet, would line both
sides of a street long enough to extend from New York to Chicago.2

"Picture yourself driving along this terribly desolated street. At
every thousand feet you pass the ruins of a building from which an
injured person was rescued. Every three-quarters of a mile there is
the blackened wreck of a house in which some one was burned to death."

' 'Imagine this street before the fire touched it, lined with houses,
stores, factories, barns, schools, churches. Suppose the fire starts at one
end of the street on the first day of January and is steadily driven forward
by a high wind, just as actually happens in a conflagration. Building
after building takes fire; and while the fire fighters save some in a more
or less injured condition, the fire steadily eats its way forward at the rate
of nearly three miles a day, for a whole week, for a whole month, for all
twelve months of the year. And at the end of 1907 did the conflagra-
tion end? No; it began on a new street, a thousand miles long, which
was likewise destroyed when 1908 was ended. And this same destruc-
tion is going on today."

The gravity of the situation is also expressed by Merrill as
follows :

"Fifteen years is a brief space of time in the history of an organiza-
tion; it is briefer in the history of a nation. Yet for our country, this
period includes the San Francisco, Baltimore, Chelsea and Bangor con-
flagrations, the Windsor, Iroquois, Collingswood, Boyertown, Slocum,

1 "The Enormous Fire Waste of the United States," Cochrane (Scientific
American, June 15, 1912).

2 Proceedings of meeting called jointly by The American Society of Civil
Engineers, The American Institute of Mining Engineers, The American
Society of Mechanical Engineers, and The American Institute of Electrical
Engineers, March 24, 1909.

280 ORGANIC STRUCTURAL MATERIALS

Lenox, Cherry, Newark, Chicago. Stock Yards and Asch disasters; not
a day without its long list of properties destroyed and not a month
without record of the sacrifice of human life. It marks a burnt offering
of more than two thousand million dollars worth of our created sources,
and the lives of more than twenty thousand of our people."1

A comparison between per capita losses in some European
countries and those in the United States is as follows (National
Board of Fire Underwriters) :

Austria (1898-1902) $0.29 Italy (1901-1904) $0.12

Denmark (1901) 0.26 Switzerland (1901-1903) . . . 0.30

France (1900-1904) 0.30 United States 2.50

Germany (1902) 0.49

In other words, the average per capita loss in six leading Euro-
pean countries is thirty cents, while the average per capita loss in
the United States is two dollars and fifty cents.

No country, however rich, can afford to suffer such losses
indefinitely; yet no great decrease can be expected until the
average building in the United States is as good, from the fire-
resisting viewpoint, as the average building in European coun-
tries. Most of the structures erected to meet first needs in the
United States were built of wood; and this, with the indiscrimi-
nate use of wood in construction at the present time, is the prin-
cipal explanation of why losses in this country have been and are
so heavy. The policy in Europe is to prevent fires; but in this
country, until recently, chief attention was given to perfecting
apparatus and organizations by which fires might be extinguished.

The present subject is part of the general field of Fire Protec-
tion. The behavior of wood while burning and its influence upon
the situation as a whole must be comprehended, but some knowl-
edge of the wider field of which the present subject forms a part
will also be of service. The notes that follow will relate to (1)
Wood as an Agent in Conflagrations and (2) Some Principles of
Fire Protection.

WOOD AS AN AGENT IN CONFLAGRATIONS

This part of the subject divides itself as it relates to the burning
of wood, the attempts to prevent wood from burning, and the methods
used to extinguish burning wood.

1 The great conflagrations that have taken place in the last and present
centuries are listed on p. 272 of World's Almanac, 1911.

WOOD AN AGENT IN CONFLAGRATIONS 281

THE BURNING OF WOOD.— Wood consists of a definite
chemical compound known as cellulose, permeated by materials
collectively known as lignin, and secretions such as resins, color-
ing matter, and water. Or, in terms of inorganic chemistry, it
consists of carbon, oxygen, hydrogen, nitrogen, and small
amounts of mineral salts that exist in the ash.

Upon burning, wood first gives off some water, after which
inflammable gases separate from a solid base of carbon; the carbon
is next largely consumed and leaves a residue of ash, which is
composed of metallic salts that were originally present, together
with carbonates formed during the burning. Wood deteriorates
and may then take fire spontaneously1 when subjected to com-
paratively slight elevations of temperature for long periods. In
most cases, however, wood takes fire from flame communicated
directly. Complex changes take place in wood as the result of
heating without access of air. They are described as follows:2

"When wood is heated in retorts, the moisture is driven out, but no
decomposition occurs until the temperature approaches 160 degrees C.
Between 160 degrees and 275 degrees C. a thin watery distillate is
chiefly formed; above 275 degrees the yield of gaseous products becomes
marked, and between 350 degrees and 450 degrees liquid and solid hydro-
carbons are extensively formed. Above this last temperature little
change occurs, and charcoal, containing the mineral ash, remains in the
retort.

"The fraction between 160 degrees and 275 degrees is called pyrolig-
neous acid, and contains the important liquid distillates, methyl (wood
alcohol), acetic acid, together with acetone, methyl acetate, allyl alcohol,
phenols, and a great many other substances.

"The fraction between 275 degrees and 450 degrees contains both
aromatics (i.e., benzene derivatives) and parafnne hydrocarbons. Its
most important constituent, from a commercial point of view, is the
creosote oil, containing guaiacol, creosol, and other phenols of high
molecular weight.

"The variety of wood used affects the amount of distillate. Decidu-
ous trees, especially birch, oak, and beech, are preferred. Coniferous
woods afford less acid (watery) distillate, but more of the higher frac-
tions containing turpentine and resin."

1 Wood should not come into contact with steam or hot water pipes and
should not be placed too near registers; otherwise deterioration and spon-
taneous combustion may result. See also "Spontaneous Ignition of Wood,"
Fairweather (Insurance Engineering, September, 1908.)

2 Quotation from Thorp's "Outlines of Industrial Chemistry."

282 ORGANIC STRUCTURAL MATERIALS

ATTEMPTS TO PREVENT WOODS FROM BURNING

Many attempts have been made to prevent woods from burning.
The ancient Greeks used alum for this purpose; and later at-
tempts were associated with methods designed to protect woods
from decay. At the present time the most intelligent efforts are
those that have followed great theater fires, and much of the
literature upon this subject relates to efforts that have been made
to protect the woods and fabrics used in theaters. The tendency
now is to eliminate woods and other combustible materials for
theater buildings.

Woods treated with certain chemicals are referred to as "fire-
proofed woods," but this is inaccurate. All woods burn under
the right conditions, and, at best, it is possible only to retard
oxidation, and to obstruct for a little the escape of volatile gases
that are active agents in spreading fires. Correctly speaking
fireproof ed woods do not exist; it is, however, correct to speak
of methods that retard burning. Protective methods are of two
kinds: fire-retarding chemicals are applied internally and
externally.

INTERNAL PROTECTION.— The attempts made to protect
woods from fire by injecting fire-retarding chemicals into them have
not yielded satisfactory results; yet the fact exists that such at-
tempts have been made and a statement with regard to this form of
protection is, therefore, necessary.1 The subject will be divided
as follows: the materials known as fire retardants, the processes
used to introduce these materials within the woods, and the
selection and preparation of woods that are to receive the fire-
retardant chemicals.

Fire Retarding Materials. — Alum^ boric acid, borax, sodium
tungstate, water glass, magnesium phosphate, aluminum sulphate,
ammonium chloride, ammonium sulphate, ammonium phosphate,
" Paris theatre solution," " Chicago solution," and many other
mixtures and compounds have been considered or used to retard
the burning of fabrics and the burning of woods. Some of these
substances serve because they decompose and liberate gases that
smother flame. Borax owes its efficiency to other properties;
it melts easily and then flows in thin films that cut off the supply
of oxygen from burning wood.

1 Fireproof ed woods were used in ships, notably after the war with Spain.
A small quantity of fireproofed wood has been used in the finish of special
buildings. At the present time the demand for such material is limited.

WOOD AN AGENT IN CONFLAGRATIONS 283

The value of ammonium phosphate as a fire retardant has been
recognized for many years. In his report upon the burning of
the Iroquois Theatre, Freeman states that no one of the many
salts or mixtures tested was found to be so good. The properties
and behavior of this salt are described in the following quotation.

" First, it has a little tendency to gather dampness, and to dry this
out absorbs a little heat. Next, as the heat rises, ammonia is given off,
and the thin film of this repels the oxygen of the air. When the am-
monia is gone we have left the ortho-phosphoric acid, which in liquid
form covers the surface and preserves it from oxidation under increasing
heat. At 300 to 400 degrees Fahrenheit this decomposes, giving off
water; at higher temperatures it gives off its remaining water. In all
of this disassociation it absorbs some heat until we have left, at full red
heat, fused metaphosphoric acid as a liquid film surrounding the fixed
carbon remaining from the destructive distillation.

"On the other hand, the phosphate of ammonia has its disadvantages.
A manufacturing chemist, perhaps of the widest experience of any in
this country in the practical chemistry of the phosphates, warns me
that for its best efficiency it must be applied in a strong or saturated
solution, but, if very strong, it may in time disastrously affect the
strength of the fiber, that it is somewhat deliquescent, has a tendency
to develop fungous growth, that in time it may part with a portion of
its ammonia, becoming the acid ammonium-phosphate which has a
tendency in presence of moisture to attack metals, while in a warm
atmosphere the free phosphoric acid attacks some colors."

The result of a series of experiments upon the comparative
worth of the several chemical substances and mixtures used as
fire retardants, conducted by Whipple and Fay, is summarized
as follows:1

(a) That inert chemical substances can exert but very slight fire-
retarding action.

(6) The fire-retarding action of salts which depend for fire-retardant
quality only upon their water of crystallization, like potash, alum,
sodium phosphate and borax, is slight and unimportant, although some-
what superior to that of inert substances.

(c) Fire retardants of the class which suffer chemical decomposition
under heating are decidedly more efficient than those which depend on
the driving off of water of crystallization, but still far less efficient than
the class that follows.

(d) The most efficient salts are those which on decomposing leave

iaA New Investigation of the Fireproofing of Fabrics" contained in
"The Safeguarding of Life in Theatres," Freeman (pp. 57-65).

284 ORGANIC STRUCTURAL MATERIALS

behind a non-volatile residue which is fluid at the temperature of the
burning canvas, and covers the charring fabric with a thin glaze which
prevents further access of air; and, of this type, phosphate of ammonium
was found to be the best.

It is necessary to distinguish between chemicals injected into
woods as fire retardants and those that are applied within woods
for other purposes. The latter are antiseptics, and woods are
the better for their presence; but as distinct from these the salts
which are applied as fire retardants attract water and in this way
injure woods.

Processes Used to Apply Fire Retardants Within Woods. — The
methods used to introduce fire retardants within woods are the
same as those employed to introduce antiseptics within woods.
There should be deep impregnation and the wood must not be
injured. Processes are of two kinds: there are some that do not
include pressure, and others that do include pressure. Solu-
tions may be applied by dipping, brush-applications, and the
open tank process; or they may be forced in by pressure applied
within cylinders.

Preparation of Woods to Receive Fire Retardants. — Woods
should be dry and receptive if fire retardants, or any other chemical
substances, are to be introduced within them. Some attention
should be paid to selection; it should be remembered that woods
differ in receptivity and that some woods, such as California
redwood, take fire less easily than others.

EXTERNAL PROTECTION. — Many attempts have been made
to prevent or retard the burning of wood by means of coatings, and
at least one of these attempts has succeeded sufficiently to serve
practically in construction.1 The properties of the materials
employed, the methods by which they are applied, and the prepa-
ration of woods to receive them, must be considered.

Materials. — Fire-retardant coatings are of many kinds. An
ideal fire-coating is one that resists the disintegration and dis-
tortion due to high heat and sudden cooling, and one that will
not conduct heat. The materials available for this purpose do
not meet these requirements satisfactorily, but they do resist the
action of fire longer than other materials. Asbestos, the so-called
fireproof paints, and certain metals, are used in fire-coatings.

Asbestos. — The name asbestos is applied to several products,
as Canadian asbestos or chrysotile, which contains about fifteen

1 See description of fire doors and fire shutters.

WOOD AN AGENT IN CONFLAGRATIONS

285

per cent, of water, and tremolite, a fibrous calcium silicate, which
contains no water. Canadian asbestos, so largely used in the
United States, loses strength and is otherwise altered by tem-
peratures, just below red heat, that are sufficient to expel the water
of crystallization.1

The fact that common asbestos becomes brittle and loses
strength when subjected to comparatively low temperatures has
discouraged its use in making curtains to isolate the woodwork
and other inflammable materials used in theaters, and such cur-
tains although still used, are no
longer regarded as the best form
of protection.2 Tenacity is less
important if asbestos is to be
used as a pigment in paint.

Fireproof Paints. — Fireproof
paints differ from ordinary
paints chiefly in that they are
not themselves inflammable.
These paints offer momentary
but sometimes sufficient resist-
ance to very small fires, such
as flames from burning matches.
But they do not resist fires
that have gained headway or
created appreciable draughts.
It is obvious that crusts less
than one one-hundredth of an
inch in thickness cannot aid effectively any attempts to
prevent conflagrations.

Lime and asbestos are common pigments, while glue and water-
glass are common vehicles. Oil should not be used. A number
of mixtures purchased in open market were found upon analysis3
to consist chiefly of slaked lime, powdered asbestos, alum, gyp-
sum, and glue. A cold water paint containing a lime, asbestos,
or magnesium base, and casein or glue as a binder, is doubtless
as good as any. Although the National Fire Protection Asso-
ciation considers well-made whitewash a good fireproof coating,

1 About 600 degrees C.

2 Steel now enters into the construction of the best curtains for proscenium
openings.

3 Whipple and Fay Report.

FIG. 45. — Corner of tin-clad
door.

286 ORGANIC STRUCTURAL MATERIALS

the use of whitewash for this purpose is not general. Some
fire-retardant paints are said to be composed of easily fusible
glass mixed with ordinary paint.

Metals. — Wood is sometimes enclosed by metal. Combina-
tions of wood and tin, such as are used for fire doors and fire
shutters, have resisted where solid metal has buckled and failed.1
Tin is superior to paint in that it resists for some time even when
exposed to severe heat, whereas paints offer but momentary
resistance even to very small fires. Paints soon blister and chalk
under the influence of heat.

Methods Used to Apply Fire Coatings. — Fire-retardant paints
are applied to surfaces of wood in the same way as other paints.
That is, it is important that the wood should be clean, dry, and
receptive; that the brush should be held at right angles to the
surface., and that the paint should be laid on with strokes
parallel to the grain of the wood.2

Tin can be applied to wood in such a way that the two together
offer a very real resistance to fire. Tin will warp, and wood will
burn, but the two, when used together in standard fire doors, have
lasted long enough to save buildings. They have retained the
shapes of the openings, even after the wood within has charred
and failed. Standard fire doors are made of not less than three
layers of seven-eighths-inch wood. The tin covers overlap at
all points so as to protect fastenings and resist strains.3

The principles that apply when woods are to be coated with
ordinary paints and varnishes apply equally when they are to
receive fire coatings. All woods should be well seasoned, dry,
and clean, if they are to receive coatings of any kind, and no wood
that is moist, knotty, or resinous should ever be used in any
fire door or fire shutter. Moisture if present would cause decay,
while, if a fire should take place, moisture and resins would form
hot gases that would burst through the tin. Clean, dry, white
pine is used in the best fire doors.

Methods of Testing " Fireproof ed" Woods. — Small specimens
are usually burned in laboratories4 and the intervals that elapse
before they are charred or consumed are taken as measures of
their resistance. Although encouraging results are obtained in

1 See descriptions of fire doors.

2 See "Paints and Varnishes Applied to Surfaces of Woods."

3 See Rules and Requirements National Board of Fire Underwriters.

4 Bunsen burners are commonly employed.

PLATE VII. APPEARANCE OF FIRE DOORS AFTER FIRE

(Facing page 286.)

WOOD AN AGENT IN CONFLAGRATIONS 287

this way, such tests have very little practical value save as they
enable comparisons, because all wood whether protected or not
will burn if the draught is sufficient.

The way in which results are influenced by methods is shown
in the case of some experiments upon so-called fireproofed canvas
prepared for use in the scenery of theatres. These experiments
are described as follows:1

"In the effort to more nearly follow practical conditions, one set of
tests was developed on the line of my earlier stovepipe experiment by
burning fireproofed canvas within a piece of five-inch stovepipe two feet
long lined with asbestos." "Six strips of the canvas, thoroughly treated
with the different solutions, were placed three-fourths of an inch apart
and ignited by burning one ounce of excelsior. In every case the canvas
burned completely to ash in from three-fourths of a minute to one and one-
half minutes, with flames which often extended two feet above the top of the
stovepipe. Tests in the stovepipe apparatus on the efficiency of different
flameproofing chemicals were made comparable by taking the same
quantity of canvas in each and by lighting the fire with the same quan-
tity of combustible."

METHODS USED TO EXTINGUISH BURNING WOODS.—

Although the methods used to extinguish all fires are the same,
yet there is good reason for associating such methods with the
burning of wood.

As already stated, in Europe the policy with regard to fires
is to endeavor to prevent them. Less wood is used in Europe
and the losses there are smaller than in the United States, where
larger quantities of wood are used and the losses that take place
by fire are larger. In the United States, until recently, more
attention has been given to perfecting apparatus and organiza-
tions designed to extinguish fires, than to means by which the
fires might be prevented.

Fire departments in Europe are inferior to those in the United
States, because less need exists for fire departments in Europe.
Those who visit European cities for any length of time are
impressed by the fact that fire engines are so seldom seen. Dur-
ing ten years passed in French and German cities Norton saw
fire engines called out five times.2 American efficiency in the

1 "A New Investigation of the Pireproofmg of Fabrics" contained in "The
Safeguarding of Life in Theaters," Freeman (pp. 57-65).

2 Journal of the American Chemistry Society (Vol. XVII, No. 2).

288 ORGANIC STRUCTURAL MATERIALS

field of extinguishing fires is unquestioned; but this is because the
demands upon firemen are so great in the United States.

Materials. — The materials used to extinguish fires act by
excluding air from the substances that are burning. It is need-
less to say that water is the cheapest, most effective, and most
widely available material for this purpose; it should not be for-
gotten, however, that other materials are sometimes used. Some
of these are as follows:

Carbon Dioxide. — It is generally conceded that much of the value
of this gas, when mixed with water as in the discharge from chemical
extinguishers, is due to the power generated, which propels the stream.
Carbon dioxide is usually used mixed with water. It is very rarely used
by itself.

Sulphur Dioxide and Ammonia. — These gases extinguish fires but are
seldom used because it is often inconvenient to obtain and apply them
and because they endanger life. They serve because they displace oxy-
gen but they cannot be used easily save in enclosed spaces of limited
extent.

Carbon Tetrachloride. — The properties of this compound were known
in the past but until recently its usefulness has been limited by its high
cost. The development of electrolytic cells for the production of chlo-
rine and caustic soda, with the consequent cheapening of chlorine gas,
has recently opened the way for the cheaper manufacture of carbon
tetrachloride.1 Carbon tetrachloride is a clear, colorless, volatile liquid,
having a specific gravity of 1.604 and a boiling point of 78 degrees C:
It is non-inflammable, non-explosive, non-corrosive, and its vapors
smother flame. It is a non-conductor and is particularly useful in the
case of electrical fires, where water cannot be employed and where dry
powders, such as sand, have previously been used. It is also serviceable
in library fires, because it will extinguish flames produced by burning
papers without injuring the papers as water would injure them.

Solids. — Flour, sand, and other solids are sometimes used in emergen-
cies. Such materials are stored in cylinders and these "dry powder
cylinders" are convenient and easily found receptacles for small quan-
tities ofthe powders used. These cylinders are useful as far as they go
but the y may do harm by causing a sense of security not warranted by
the results obtained. The National Fire Protection Association reports
as follows:

"In view of the fatct that several so-called fire extinguishers, consist-
ing generally of sheet-metal tubes filled with mixtures of bicarbonate of

1 Journal Industrial and Engineering Chemistry (January, 1910) ; Engineer-
ing News (March 16, 1911); Quarterly National Fire Protection Association
(January, 1911); Catalogues Pyrene Manufacturing Company; etc.

WOOD AN AGENT IN CONFLAGRATIONS 289

soda and other materials in powdered form, have been widely advertised
as suitable for use for fire-extinguishing purposes, we have to report
that in our opinion all forms of dry-powder fire extinguishers are inferior
for general use, that attempts to extinguish fires with them may cause
delay in the use of water and other approved extinguishing agents, and
therefore their introduction should not be encouraged."

Methods or Devices for Applying Materials. — Water is applied
by steam fire engines and other devices commonly associated
with the elaborate fire departments of cities. Tanks placed
at high elevations are often useful where natural head is not
available. Chemical engines, sprinklers, and fire pails are also
employed.

Chemical engines are tanks containing bicarbonate of soda
dissolved in water, and commercial sulphuric acid (oil of vitriol)
stored separately but also within the tank. The carbon dioxide
which results when these compounds come together creates the
force by which the contents of the extinguisher is discharged.1

Automatic sprinkler systems consist of pipes arranged on the
ceilings of rooms within the structures to be protected. Water-
ways in these pipes are closed by small discs which are held in
place by easily fusible solder. In case of fire the solder melts,
water flows upon the fire, and an alarm is rung. There are many
other important details,2 some of which are noted later in the
present chapter.

Portable chemical fire extinguishers differ from the larger
chemical engines that have been described in that they are easily
carried from place to place, and very easily manipulated. The
copper receptacle, coated with tin, is designed to hold about three
gallons of water, and to resist a pressure of about four hundred
pounds, although the pressure seldom exceeds eighty pounds.
The quantities of acid and soda are adjusted so that the pressure,
when they come together, is not greater than the cylinders can
bear. The solution that leaves the extinguisher should be alka-
line rather than acid, since acid solutions are more liable to
damage the materials upon which they are thrown. Extin-

1 Requirements for Proper Installation of Chemical Fire Extinguishers
(Published by The New York Fire Insurance Exchange, 19 13).

2 Rules and Requirements of the National Board of Fire Underwriters
for Sprinkler Equipment, 1913.

290 ORGANIC STRUCTURAL MATERIALS

guishers should be recharged at stated intervals; their contents
should always be fresh and active.1

The extinguishers become active when they are inverted.
The stopper then drops away from the mouth of the acid flask.
The acid mixes with the soda solution, and the conditions neces-
sary for operation are obtained. Extinguishers should not be
inverted until operators are in the presence of the fires, since the
streams last only about eighty seconds. They should be stored
in conspicuous places, where those who are to use them can find
them easily. Care should be taken so their
contents will not freeze.

Fire pails are less effective than chemical
extinguishers, because their contents cannot
be propelled as accurately or as far. Fire
pails should be painted red so that they
can be identified if thoughtlessly removed
from their accustomed places for othei
service. They should always remain in the
FIG. 46. — Section same conspicuous and convenient places, and

through portable fire care shOuld be taken to prevent their contents
extinguisher. .

from freezing. The pails should be inspected

frequently as a safeguard against leakage and evaporation.
The value of fire pails has been described as follows :2

A pail of water is the best fire extinguisher yet devised. It costs
little; its use is understood by everyone; it is easily kept ready for use;
and its effect, if used at the proper moment, may be better than the work
of an entire fire department five minutes later. The value of fire pails
has come to be recognized, not only by the insurance community and
by practical firemen, but also by all other persons having a care for the
safety of life and property. Accordingly, it is a common practice for
property owners, of their own accord, to have pails of water ready, in

1 The directions that appear upon extinguishers of a certain approved type
are as follows: "Fill the receptacle with two and one-half gallons of water,
add two and one-half pounds bicarbonate soda; stir well to dissolve. Fill
to acid line with four fluid ounces of sulphuric acid and place stopper in
bottle, and bottle in cage. Screw cap down tight. Protect from freezing.
If i used, clean well and recharge. Discharge, clean well and recharge
yearly. Record date when charged." See also "Requirements for Proper
Installation Chemical Fire Extinguishers" (Published by New York Fire
Insurance Exchange, 1913).

2 " Requirements for Proper Installation of Fire Pails" (Published by
The New York Fire Insurance Exchange, 1909).

WOOD AN AGENT IN CONFLAGRATIONS 291

case of fire; in addition, the officers of local fire departments use their
authority to bring this about, and fire insurance organizations have not
been lacking in encouraging the insuring public to equip their premises
with this simple means of fire protection.

The New York Fire Insurance Exchange, in common with other in-
surance organizations, has placed a premium on fire-pail equipments by
granting a liberal reduction in rates, where the premises of an assured con-
tain fire pails, maintained in a manner which assures a fair probability
of their being ready for use when needed. Fire pails are useful only
when they are filled, within easy reach, and near at hand; and in order
to provide some guarantee of efficiency, the fire insurance community
has been obliged to adopt certain rules regarding fire pails, and to make
a proper observance of these rules a condition to granting the reduction
in rates. These and similar fire insurance rules are the result of more
than fifty years' experience with the insuring public, who, with the best
of intentions, frequently install costly fire protection equipments,and then
take no steps toward keeping them in condition for use when fire occurs.

In the case of fire pails, for example, it has been found advisable to
require that the pails be painted red, with the word "FIRE" or "FOR
FIRE ONLY" in black letters of a certain size. The red color is useful
because of its general association with fire; it helps to make the pail
clearly visible when wanted; and, with the word "FIRE," is a constant
reminder that the pail is there for a special purpose, the putting out of
fire, and is not to be taken away or used for ordinary purposes. The
placing at a medium height is devised to permit of grasping the pail with-
out spilling half its contents; if a pail is placed more than five feet high,
it is likely to be out of the reach of the average person; and if set lower
than two feet, it is likely to be overlooked or to be knocked from its
position. The use of an iron pail in preference to a pail of wood or other
material, is a matter of service and economy, in addition to the greater
likelihood that an iron pail will be found serviceable when suddenly
wanted for use. The requirement of a stated number distributed in
groups throughout the entire premises, is framed to provide that pails
shall be within a hand's grasp, and not be distant anywhere from 50
to 200 feet at a time when a tiny flame is rapidly growing into a formid-
able blaze. The insistence of a permanent setting, such as hooks or
shelves, is intended to make sure that the pail will be given a fixed posi-
tion, which will become familiar to the occupants who, in time of excite-
ment, can rely on finding pails in a definite spot. The regular re-filling
is a common-sense precaution to make sure that the pails shall contain
water. Such rules as these are part of the usual discipline maintained
in establishments which have in view a careful management of the
property, and they are published in the belief that a proper observance
of them will tend to reduce the loss suffered by the community from the
effects of fire.

292 ORGANIC STRUCTURAL MATERIALS

When fire pails are located where there is a liability of the water
being frozen in cold weather, it is recommended that 2 pounds of chloride
of calcium or salt (the chloride of calcium is preferable), be placed in
each pail. For casks the quantity recommended is fifty pounds for
each cask. It is necessary that the chloride of calcium or the salt be
dissolved by thorough stirring.

Organization. — It should be remembered that fire losses are
caused by failure and the misuse of apparatus as well as by its
absence. The efficiency of the best apparatus is limited by the
way in which it is used, and, for this reason, the highest efficiency
is seldom obtained outside of large cities where there are paid
fire departments. The danger from fire is less where those in
charge of apparatus are taught how to use it before an actual
emergency takes place. A plan of action should be formed and
all details be considered before a fire takes place.

SOME PRINCIPLES OF FIRE PROTECTION

• For completeness some space is given to the general field of
Fire Protection.

It was stated that the policy in Europe is to prevent fires, but
that in this country, until recently, the principal demand has
been for means to extinguish them, and that this difference
explains why losses are so much greater in this country than in
others. Fires may be prevented by eliminating the factors that
are known to cause them, one of which is wood.

One reason why preventive practices are emphasized in
foreign countries is because wood is less plentiful in such coun-
tries. These practices were not introduced suddenly, but grew,
little by little, as local supplies of wood gradually decreased.
It was the law of necessity that, in Europe, caused the substitu-
tion of non-inflammable materials for wood, and already the
same law is beginning to serve similarly in the United States.

The conditions in Europe and in this country differ in that
larger proportions of what may be called " final constructions"
exist abroad where civilization is older. That which is regarded
as mere neglect or misfortune here, is considered there more as
though it were a crime. The police in Berlin have very real
authority over every detail that is likely to increase danger
from fires, while citizens of France are held legally responsible for
fires that pass from their own homes to those of others:

WOOD AN AGENT IN CONFLAGRATIONS 293

Preventive practices in the United States had their origin in
the factory districts of New England, and some of the best and
most modern details in this field have been evolved by manu-
facturers in those sections. The National Fire Protection Asso-
ciation, the National Board of Fire Underwriters, Factory Mu-
tuals, and other organizations now exist to study causes and
suggest methods by which fires may be prevented.

The organizations alluded to occupy a field in this country
that suggests the one occupied by paternal governments abroad.
Very much has been accomplished by them already, but improve-
ment to the point of the average conditions that exist in older
countries cannot be hoped for for some time to come. Many
structures that were erected to meet first needs in the United
States have already given way to others, better and more per-
manent, but much remains to be done. The rebuilding of a
country is a very slow process.

It will be remembered that the preceding section was devoted
to a study of the material Wood when burning, and that the text
was presented under the titles "Burning of Wood," "Attempts
to Prevent Wood from Burning," and "Methods Used to Extin-
guish Burning Wood." As distinct from this, the subject of
Fire Protection is devoted to a study of burning Buildings and
the parts of this subject will be grouped as they relate to (1)
"Burning of Buildings," and (2) "Method by which Buildings
are Prevented from Burning."

Burning Buildings. — Such fires may be classified as they
originate within the buildings, or as they are transferred from
without. The latter are known as "exposure fires," and a large
proportion of the destruction that takes place in this country is
of this type.

The superiority of the average European building, from the
fire standpoint, is shown by the fact that a larger proportion of
the fires in Europe are confined to the buildings in which they
start. Aside from fires due to warfare, the great conflagrations
that have taken place in all Europe during several centuries have
destroyed less property than those that have taken place in the
United States alone during a single century.

The destructive temperatures in burning buildings vary
between 1,500 degrees Fahrenheit and perhaps 2,500 degrees
Fahrenheit. Drafts and air currents must also be considered.
Materials may be injured not only by heat, but, also by sudden

294 ORGANIC STRUCTURAL MATERIALS

cooling, as when streams of water are applied to them suddenly
while they are hot.

Methods By Which Buildings Are Prevented From Burning.
—It is doubtless true that in the United States some general
fires have been prevented by the presence of parks, streets, and
other open spaces, and by the moderate heights of structures;
but great fires, that have few counterparts in European history,
have taken place in Portland, New York, Chicago, Boston,
Jacksonville, Paterson, Baltimore, San Francisco, and Chelsea.

The first real attempts to reduce fire losses came when brick
and stone were used instead of wood for outside walls. Walls of
brick and stone were made to support floors and roofs of wood,
and buildings of this kind resisted better than those of the earlier
type, because they offered more resistance to outside fires.1

Later attempts included the use of iron and steel, but these
materials were not protected as they are at the present time.
The high conductivity of iron and steel, and their tendency to
expand under comparatively small increases of temperature
caused these unprotected beams and columns to bend and collapse
even in very small fires. Buildings constructed in this manner
were but little better than those of wood.

Buildings are now designed to stand against both inside and
outside fires. A fire may destroy the inflammable contents in a
room or other section of such a building, but it will not normally
reach over into another room or section of the building. Details
relating to materials, design, special devices and the care of the
buildings after they are erected are all important. It should be
constantly remembered that the building may be strictly fire-
proof but that its contents, as distinct from the building itself,
may be inflammable, and that such contents, if too great in
quantity, may cause the destruction of the building.

Materials. — It is obvious that the best way to prevent a structure
from burning is to build it of something that will not burn. Yet it
must be remembered that some materials that do not burn are not to
be regarded as fireproof. A really fireproof material will not only resist
the disintegrating and distorting influences due to high heat and sudden
cooling, but it will not conduct heat.

1 $68,000,000 of the total loss in the United States in 1907 took place in
buildings composed of brick, concrete, stone, and similar materials; while
the loss in wooden buildings during the same year was over twice as much,
or about $148,000,000.

WOOD AN AGENT IN CONFLAGRATIONS

295

FIG. 47.—

Metals. — Iron and steel are poor fireproof materials when used alone.
This is because they warp and conduct heat, and it is only after they
are protected by non-conducting substances that they become valuable
in fireproof constructions.

Natural Stones. — Stones differ greatly in their ability to stand against
heat. Granites disintegrate because they contain water, and because
the component minerals do not have the same coefficients of expansion
and contraction under heat and cold. Limestones lose their carbon diox-
ide and are reduced to ordinary building lime under the influence of
heat. Most sandstones stand against fire better than all limestones,
and far better than all granites.

Artificial Stones. — The prop-
erties of brick are influenced
by the properties of the clays
used in their manufacture.
Good brick is one of the best
of all fireproof materials.
Enamelled brick is often
very good. Terra cotta,
whether used in bricks, or
for ornamental work, or as a
protective coating for iron
and steel, is a very valuable
fire-resisting material. Con-
crete possesses the additional advantage that it can be laid without
joints.

Combinations. — The best results are obtained by the use of all-metal
members protected by brick, terra cotta, concrete, or other non-con-
ducting materials. Hollow brick, terra cotta, and concrete, are used
for walls, floors, and ceilings.

Influence of Design, Special Devices, Etc. — An ideal building has out-
side walls of brick. Its frame is made of steel or iron covered with some
material that will stand against heat. Floors and roofs are built of
hollow tile, terra cotta, concrete, or other non-conducting or fire-resist-
ing materials. All stairs, elevators, and dumbwaiters are enclosed by
brick shafts with standard, tin-clad fire doors in all openings. Wells
for light are enclosed by brick, and the windows in the wells are of wired
glass in standard metal frames, and these materials are also used in
outside windows. Standard fire doors, or their equivalents, are used
in door openings. A low building is safer than a high building. An ideal
building is restricted in height and floor areas so that all parts can be
swept by fire streams under prevailing pressures. Heights and areas can
be increased if the entire building is protected by automatic sprinklers.

Roofs. — Roofs are either fireproof, semi-fireproof, or inflammable.
Roofs covered with slate, tile, and some special materials are in the first

;e protected by duplicate
re doors.

296 ORGANIC STRUCTURAL MATERIALS

group; while those made of tin or corrugated iron spread upon wood
are in the second group. Shingled roofs, which are in the third group,
are highly inflammable. A large proportion of all outside fires are caused
by sparks lodging on roofs.

Door Openings. — Fire doors, designed to obstruct the passage of heat
and flame through door openings, are used in pairs, one door being
placed at each one of the two surfaces of the wall through which the
opening extends. Automatic doors, that close when the heat becomes
sufficient to fuse a link of special metal, are generally recommended.
Latches, locks, hinges, slides, and other details are highly important.
The efficiency of the standard fire door is expressed in the following
quotation.1 " Recent tests and investigations indicate that for openings
of ordinary size the so-called standard tin-clad door and shutter, all
things considered, furnishes the most reliable protection, particularly
when the exposures are severe. The superiority of this type is very
largely due to its efficiency as a non-conductor of heat. This offsets, in
a large measure, inherent defects in other respects, such as the bulging
of the plates by the gases generated from the inflammable materials
now used in its construction, the falling down of the core after it has
been reduced to charcoal, and its comparative lack of endurance under
severe exposures."

Window Openings. — Water curtains and iron shutters were formerly
used to protect window openings, but these devices have given way to
standard fire shutters, and wired glass windows. Tin-clad fire shutters
are similar to the standard fire doors that have been described; while
the wired glass is used, as has been noted, in metal frames. The re-
quirements of both inside and exposed fires must be recognized.

The value of wired glass windows in resisting the action of moderate
fires depends upon the character of the glass and sashes. Glass softens
and drops away when a temperature of about 1,500 degrees F. is reached.
Sashes and frames are made of hollow steel and other metal. There are
three types : the pivoted sash, which is automatic, the double hung sash,
and the casement sash. Locks, hinges, and other hardware are im-
portant factors. Ordinary putty must not be used.2

Fire Shutters. — The principal difference between fire shutters and
fire doors is noted in the rules prepared by the National Board of Fire

1 Abstract of Committee Report presented at annual meeting of National
Fire Protection Association, New York City, May 23-25, 1905 (Engineering
News, Vol. 53, No. 22). Also Rules and Requirements for the Construction
and Installation of Fire Doors and Shutters recommended by the National
Fire Protection Association (Edition of 1906).

2 Rules and Requirements of the National Board of Fire Underwriters for
the Manufacture of Wired Glass and the Construction of Frames for Wired
and Prism Glass used as a Fire Retardant.

PLATE VIII. DETAILS OF TIN-CLAD FIRE DOOR

-J-T-

^r-r

(c) Method of Joining and Fastening
Tin.

(a) Application of
Tin to Corners of Fire
Door.

(6) Method of Holding
Layers of Core together
by Clinched Nails.

(d) The Completed Door.

(Facing page 296.)

WOOD AN AGENT IN CONFLAGRATIONS

297

Ell— J

Underwriters as follows:1 " Construction to be the same as for fire doors,
except that only two thicknesses of % inch boards are required. Layers
of boards to be at right angles."

Automatic Sprinklers. — It is a important to have fires discovered and
extinguished while they are small, and apparatus Designed with these
ends in view may be properly classed among prevent ative devices.

General information with respect to automatic and open sprinkler
equipments, prepared by the National Board of Fire Underwriters, is
as follows : 2

1. Preparation of Building. — Many buildings require preparation for
sprinkler equipment. All needless

ceiling sheathing, hollow siding, tops
of high shelving, needless partitions or
decks should be removed. Necessary
" stops" to check draft, necessary new
partitions, closets, decks, etc., should
be put in place so that the equipment
may conform to the same. The top
flooring should be made thoroughly
tight.

2. Accessory Woodwork. — Sprinkler
equipments require accessory wood-
work, dry pipe valve closets, ladders,
anti-freezing boxing for tank pipes, etc.
This work should be promptly at-
tended to if not let with sprinkler
contract.

3. Drapery and Sheathing. — Paper or similar light inflammable ceiling
sheathing is objectionable and unnecessary. Where floors leak dirt, an
acceptable sheathing may be made of lath and plaster, matched boards
or joined metal. All channels back of sheathing to be thoroughly closed
between timbers or joists. Sheathing to be tightly put together and
kept in repair. In mill bays, sheathing to follow contour of timbers
without concealed space.

1 Rules and Requirements for the Construction and Installation of Fire
Doors and Shutters as recommended by the National Fire Protection
Association (Edition of 1906).

2 Rules and Requirements National Board of Fire Underwriters governing
the Installation of Automatic and Open Sprinkler Equipments as recom-
mended by the National Fire Protection Association (Edition of 1913).

3 This window was in Newark works of Sherwin-Williams Company.
The picture shows appearance after fire had destroyed adjacent works of
Consolidated Color and Chemical Company. The fire did not pass
through this window, although the heat was sufficient to burn the paint
from frame and sash (Insurance Engineering, November, 1907).

FIG. 48. — Wired glass window
in metal sash. 3

298 ORGANIC STRUCTURAL MATERIALS

4. Vertical or Horizontal Drafts. — Floor or wall openings tending to
create vertical or horizontal drafts, or other structural defects that
would prevent the prompt operation of automatic sprinklers by prevent-
ing the banking up of the heated air from the fire, should -be properly
"stopped" in order to permit specific control by the local sprinklers.
Satisfactory curtain-boards and other draft-stops must be provided to
overcome such structural defects.

5. Clear Space Below Ceilings. — Full effective action of sprinklers re-
quires about 24 inches wholly clear space below roofs or ceilings; this
loss of storage capacity should be realized in advance of equipment.

6. Experienced Workmen Recommended. — Sprinkler installation is a
trade in itself. Insurance inspectors cannot be expected to act as work-
ing superintendents, nor correct errors of beginners. Sprinkler work
should be entrusted to none but fully experienced and responsible parties.

7. All Portions of Buildings to be Protected. — Experience teaches that
sprinklers are often necessary where seemingly least needed. Their
protection is required not alone where a fire may begin, but also wherever
any fire might extend, including wet or damp locations.

8. Degree of Protection. — A maximum protection cannot be expected
where sprinklers are at more or less permanent disadvantage, as in the
case of stocks very susceptible to smoke and water damage, buildings
having deep piles of hollow goods, excessive drafts, explosion or flash
fire hazards, or large amounts of benzine or similar fluid.

9. Necessary Cut-offs. — Sprinklers cannot be expected to keep out fire
originating in unsprinklered territory. Stringent measures should be
used to properly cut off all unsprinklered portions of buildings or
exposures.

10. Communications. — When a building fully equipped with sprink-
lers communicates with another not so equipped, the openings must be
protected by standard fire doors on both sides of the walls, one of which
must be automatic.

11. Protection Against Exposures. — The danger of sprinkler protection
being impaired by exposure fires should be reduced by providing
adequate shutters, wired glass or open sprinkler protection at exposed
windows.

Signals. — There are automatic and non-automatic signals. An auto-
matic thermostat alarm depends upon the opening and shutting of an
electric circuit in a thermostat. Such alarms are used in connection
with automatic sprinklers. Non-automatic alarms should be practical,
conveniently located, and easily understood.

Care or Maintenance of Structures. — The contents of a building are
as important as the building itself. The building may be composed of
materials that will not burn, yet it may be injured or even destroyed
by fires in contained oils, cotton, or similar stores. The quantity of
such inflammable stores should always accord with the capacity of the

WOOD AN AGENT IN CONFLAGRATIONS 299

building to resist fires and with its capacity to isolate them so that they
will not spread from one section to another.

Cleanliness and Order Are Imperative. — Trash should not be permitted
to accumulate. Oiled rags or waste should be destroyed, or kept in
metal boxes. Matches should also be stored in metal boxes. Smoking
must often be prohibited. Systematic inspection is usually necessary.
Managers should be held responsible by night as well as by day. It is
not enough for them to employ watchmen. They should be certain
that such assistants, who are usually selected for physical rather than
mental gifts, really perform their duties. Watchmen work alone and
without direct superintendence, and, for this reason, their duties should
be planned for them.

Watchmen's Recorders. — The services of watchmen are systematized
by means of mechanical devices known as recorders that compel the
watchmen to visit certain stations at certain stated intervals. These
recorders are of three kinds. There are portable time recorders, station-
ary time recorders, and central office recorders.1

Portable Time Recorders. — The recorder resembles an alarm clock and
contains a paper dial, turned by clock movement, upon which an impres-
sion is made whenever a key is used. There are several such keys, with
but one recorder, which last is carried by the watchman, while the keys
are chained at the several stations to be visited. The records shown
by the paper dials indicate the time when each key was used. This
system is simple and economical in its first cost, but it is objectionable
because of the weight of the recorder and because of the fact that watch-
men sometimes obtain duplicate keys.

Stationary Time Recorders. — In this system there is one key and sev-
eral recorders. The watchman carries the key and the recorders are
fixed at the stations. Some recorders contain paper record forms which
are collected in the morning, and others are wired so that the records
are received on a single dial in the superintendent's office. A stationary
time recorder system is good because watchmen do not have to carry
the more or less heavy recorders, and because it is difficult to tamper
with the records. The weak points are the increased first cost, and the
labor required to collect the records in the morning. When such labor
is rendered unnecessary by connecting the recorders with the superin-
tendent's office, there is extra cost for wiring.

Central Office Systems. — The central office system enables a superin-
tendent, located at a central office, to reach and control the movements
of his men at all times while they are on duty.

1 New York Fire Insurance Exchange Bulletin, No. 5. Also literature
published by Newman Portable Clock Company, American Watch System,
etc., etc.

CHAPTER XII

FAILURE OF WOOD BECAUSE OF ANIMAL LIFE. MARINE AND
TERRESTRIAL FORMS. METHODS OF PROTECTION

The forms of animal life that attack woods may be divided
according to their habits or environment into marine woodborers1
and terrestrial woodborers.

The quantity of wood destroyed by marine woodborers is
considerable, but the proportion is much smaller than it was
when wood was used more extensively in marine constructions.
The total value of wood destroyed by marine borers is much less
than the total value of woods and living trees destroyed by
terrestrial borers.

MARINE WOODBORERS

The harm done by these borers has not always been measur-
able by direct costs, since it is recorded that owners of wooden
ships once discriminated against harbors in which numbers of
these pests were known to be -present.

Most . perforations found in timbers that have been in sea
water are attributed to the Teredo navalis, probably because
this shipworm was one of the first to be studied and was the one
selected for description in some of the earlier text-books. The
Teredo navalis is worthy of the attention it receives, but it must
not be forgotten that there are other marine woodborers.

THE SHIPWORM (Teredo, Xylotrya, etc.).— This is a general
name that applies to several species of mollusks of the genus
Teredo, together with other species in other genera. The mol-
lusks known as shipworms are characterized by the fact that they
bore in wood, and are represented, along the north-central Atlantic
Coast, by species of the genus Xylotrya.

Shipworms are widely distributed throughout the waters of
the tropics, and are present in smaller numbers in cooler waters of
temperate regions. They inhabit European waters from Sweden

1 The first part of this chapter is based upon the author's paper entitled
"Marine Woodborers" published by the American Society of Civil Engi-
neers (Transactions, Vol. XL, 1898). Some of the pictures prepared for the
original paper are used with the permission of the said Society.

300

MARINE AND TERRESTRIAL WOODBORERS 301

to Sicily, and are also found in the vicinity of Bermuda, the West
Indies, New Zealand, and Australia. In the United States they
exist from Maine to Florida, and along the Pacific Coast as far
north as Alaska. The United States Fish Commission reports
their distribution in local waters to be as follows :

Teredo navalis, between Florida and Cape Cod. Teredo norvegica,
Cape Cod northward to Maine. Teredo megotara, New Bedford, south
to South Carolina. Teredo dilatata, Massachusetts to South Carolina.
Teredo thompsoni, Massachusetts. Xylophaga dorsalis, North Atlan-
tic. Xylotrya fimbriata, Long Island Sound to Florida.

Form. — The form of the shipworm is shown in the picture.
It is a long, worm-like organism of which the posterior end s
remains at the outer surface of
the timber, while the other or
anterior end B occupies the
inner extremity of the tunnel.
The two horn-shaped structures
s are the free extremities of other-
wise united tubes, known as

siphons, that pass throughout FlG 49._The shipworm.

the entire length of the ship-
worm to the vital organs and boring shell at B. These horn-
shaped extremities are the only parts of the shipworm that can
extend outward beyond the wood, and are therefore the only
parts that are evident to the casual observer.

A general idea of the form of the shipworm may be gained by
examining the ordinary long, or soft-shelled, clam (Mya arenaria)
so familiar to residents of New England. This clam possesses a
very long worm-like neck penetrated by two parallel tubes or
siphons through one of which water, oxygen, and food pass in-
ward, while through the other exhausted water and debris pass
out. It is also helpful to examine the common razor clam (Ensis
directus) which, besides siphons, possesses a powerful, muscular
club-shaped foot or sucker that enables it to bore into the sand.
The long and razor clams and the shipworm are all true mollusks,
and each one suggests a worm only because the part that sur-
rounds the siphons is soft and cylindrical.

The parts of the shipworm that are important in the present
connection are the body, siphons, collar, pallets, boring shell,
foot, and lining shell. These parts will be considered separately.

302

ORGANIC STRUCTURAL MATERIALS

The Body. — The translucent substance of which the body is composed
resembles the living substance in the body of the oyster. In some
species, in addition to their normal functions of respiration, the gills
perform the important office of sheltering the embryo. The nervous
system is well developed. Vital organs, such as the liver, are protected
by being enclosed within the boring shell. The stomach is not distin-
guished by any peculiarity. There is a long intestine.1

The Siphons. — The siphons extend through almost the entire length
of the body. One of them conveys the oxygen, water, and infusorial

food to the digestive organs;
while the other conveys the ex-
hausted water, excretions, and
wood particles from the excavation
to the free water without.

The siphons are joined together
for most of their length, but separate
as they pass outward at their
extremities, s, and are then* capa-
ble of being thrust out and with-
drawn through the orifice in the
wood. They are the only parts
that can be seen from the outside
of the wood. It will be noted that
these extremities must always re-
™* * the orifice to the tunnel.

When the conditions are favora-
ble, the extremities of the siphons are

extended out to their full length beyond the surface of the wood. Other-
wise, they are withdrawn and there is then but little evidence that the
shipworm is within the piece. The picture shows the siphons as they
appeared fully extended after several consecutive days of warm weather.
The Collar. — The collar C is a muscular, wrinkled membrane that ex-
tends around the posterior portion of the shipworm at the point of union
between the siphon and the body proper, and forms
a connection between the body and the calcareous
lining of the tunnel. This is the only place at
which the body of the shipworm is not free and
separated from its surroundings. The collar in-
cludes .several well-defined muscles and these act
upon the small shells known as pallets by which the FlQ 51 _ pauets.
entrance to the perforation may be guarded.

The Pallets. — The two shells or plates, located at p and called pallets,
are broad, slightly curved and flattened at the top and contracted at

the wood.

Sigerfoos (Circular Johns Hopkins University, June, 1896).

PLATE IX. WORK OF THE SHIPWORM

Surface of Wood recently Occupied by Shipworms. Life Size.

Section Parallel to Face Shown in Preceding Figure. Life Size.

Vertical Section through Preceding Figures. Life Size.

(Facing page 302.)

MARINE AND TERRESTRIAL WOODBORERS

303

the bottom where they pass under the collar. When the siphon ex-
tremities are withdrawn into the body, the tops of the pallets are brought
together over them and protect them. These shells are sometimes con-
fused with the boring shells, which are quite distinct, and at the other
end of the body. Details differ with species.

The Boring Shell. — The principal or boring shell B is small and very
beautifully formed. The two parts together are nearly as long as they
are broad, and present an
irregular triangular appear-
ance when observed from
the side. They close tightly
at the hinge and at the side
opposite. As distinct from
this, however, an open space
at the top permits the body
to emerge while a similar
opening at the bottom is for
the foot or sucker. The
shells of young shipworms
are much larger in proportion
than those of older ship-
worms, and when the worm
is very young, it is for a
short time entirely enclosed
in its shell.

The Foot. — The foot, which in form resembles a pestle, is a short, stout,
muscular organ, broadly truncated or rounded at the end, and so ar-
ranged that it can exert a powerful suction upon anything to which it
is attached. The extent to which this cupping action assists the exca-
vating has probably been underestimated.

The Calcareous Lining. — Calcareous material deposited upon the
woody surface of the tunnel forms a smooth lining along which the body
of the shipworm can pass as it contracts or expands. This shell-like
tube is distinct from the pallets and from the boring shell. Its thick-
ness, which varies with species, is sometimes so slight that the shell is
detached by the slightest shock, and many specimens, exhibited in
museums, do not show the lining for this reason. The lining is some-
times very thick. The shipworm can rarely advance through the wood
very far in a straight line, but is forced to pass here and there so as to
avoid obstacles such as cracks, knots, and the tunnels of its companions.
In such cases, the linings are curved as they wind in and out, and
often so many are present that almost the entire content of the
wood is occupied. Shipworms avoid seams and joints in wood, possibly
because of their effect upon the calcareous linings.

FIG. 52.— The boring shell.

304

ORGANIC STRUCTURAL MATERIALS

Physiology. — Shipworms live principally, if not wholly, upon
organic particles obtained from sea water. Particles of wood are

sometimes found in their intestines,
and it is not certain that these
particles, cut from the burrows, do

FIG. 53. — End view of dis-
section shown in figure which
follows. (Life size.)

not serve in some minor
way as food. It is certain,
however, that the principal
reason for the boring is to
prepare a shelter.

A shipworm can live for
a short time out of water.
But, since it derives its sus-
tenance from the water, it
must have access to it much
of the time. It does not
have to be submerged all
of the time, and can live
and work under such con-
ditions as exist between
tide levels. It has been
known to live for about
two weeks in timbers that
have been transferred from the sea to fresh water, and could
possibly have lived longer than two weeks.

FIG. 54. — Dissection showing calcareous
lining in wood. (Life size.)

MARINE AND TERRESTRIAL WOODBORERS 305

Many logs in a cargo of Central American woods recently received
in New York, after a voyage of about two weeks, were found to be full
of living shipworms that had gained entrance while the logs were waiting
for shipment in the South. The shipworms were apparently in good
condition when the timbers were removed from the hold of the ship.
The wood itself, and the hold of the ship, contained considerable water,
yet the logs were by no means submerged, and the fact exists that these
particular specimens survived during a voyage of about two weeks.
They were very numerous, so much so, that later the logs had to be
removed from the yard because of the odor.

Reproduction and Development. — Most mollusks reproduce by
means of eggs, which, in the case of some shipworms, are spheri-
cal in shape and greenish yellow in color. Shipworms are very
prolific, the eggs of a single specimen being numbered by the
million. The eggs are very hardy and many survive and yield
young shipworms. A shipworm can swim at the end of about
three hours after hatching and has a well-developed shell before
the end of the first day.

The shipworm passes through several stages before it assumes
the character and form of the adult. It is first covered with fine
hairs or cilia, which enable it to swim. Soon most of the cilia
are lost and the rudiments of a small bivalve shell appear. At
first, this shell is heart-shaped and very small, yet it is large
enough to enclose almost the entire body. The portion of the
body that protrudes from the cell is fringed with cilia, and these
enable it to continue to swim until it finally encounters a piece
of wood.

The results of some observations upon the shipworm (Xylotrya
fimbriata) at Beaufort have been summarized by Professor
Sigerfoos as follows:1

"The free-swimming stage is reached in three hours, and a well-
developed shell is formed in a day. We have no direct observations as
to the time the ship larva is free-swimming. We may assume, I think,
that it is at least a month, or it may be two. Most of its energies are
devoted to locomotion during this period, but, after it has attached
itself, all of its energies are devoted to forming its burrow and securing
its food. Coming into contact with the wood, the larva throws out a sin-
gle, long byssus thread for attachment and never again leaves its place.
The newly attached larva is somewhat less than 0.25 mm. long. In
twelve days it has attained a length of 3 mm.; in sixteen days, 6 mm.;

Johns Hopkins Circular, June,

306 ORGANIC STRUCTURAL MATERIALS

in twenty days, 11 mm.; in thirty days, 63 mm.; and in thirty-six days,
about 100 mm., when it bears ripe eggs or sperm."

The time of reproduction is important. In the vicinity of
New York, this takes place principally during the month of May;
but it may continue, although to a less extent, throughout the
greater part of the summer. In tropical countries, it probably
goes forward throughout the entire year. Although the extreme
life limit of a shipworm is unknown, it is thought that individuals
can live for several years under favorable conditions. A ship-
worm may attain to a comparatively large size during a single
season.

Influence of Temperature and Water. — In most cases ship-
worms are more plentiful where the water is not cold, and, for
this reason, wood is destroyed more continuously and more
rapidly in the tropics and semi-tropics. In the United States
destruction is most serious along the entire Pacific Coast, as
well as along the coast of the South Atlantic and Gulf States.
Some shipworms are found, although they are much less active,
where it is often extremely cold, as in Maine and Alaska.

Some shipworms thrive in pure sea water, while others do well
in brackish, impure, or comparatively fresh waters. Sometimes
the parts of timbers that are near the surface of the water are
injured, and sometimes the parts that are down near the bottom.
These and other differences are accounted for by the facts that
there are many species of shipworms, and that differences some-
times exist between the qualities of higher and lower layers of
water. For example, when fresh water from a river meets the
heavier water of the sea, shipworms may sometimes be found near
the bottom where the water is actually salt.

Some shipworms (Xylotrya fimbriata) survive in the brackish, polluted
waters of New York Harbor, while other species that do not exist in
these waters are present in the nearby ocean. Shipworms are very
active along the north Pacific Coast but are said to be absent at some
points near the mouth of the Columbia River because fresh water pre-
dominates at these points. A vessel carrying hardwood logs was
wrecked in the vicinity of the Gulf of Mexico. The logs were conveyed
to the sheltered, but brackish, waters of a creek where they remained
for about six weeks. The pieces were attacked as soon as they were
placed in the creek and the results were so noticeable that some borings
were measured and are said to have been six inches in length. The

MARINE AND TERRESTRIAL WOODBORERS 307

wood that remained in the outer ocean was not injured.1 The dis-
crepancies between these incidents may be accounted for by the presence
of different species of ship worms.

The belief that shipworms are influenced by impurities in
water was expressed in Holland as early as 1733. It was noticed
that comparatively little rain fell in years when shipworms were
quite plentiful, and it was thought that the diminished volumes
of river water during these years permitted larger quantities of
salt to exist in the waters near the mouths of the rivers. Analyses
proved that the proportions of salt did vary during the dry and
rainy seasons.

Method of Attack. — While the ship worm is yet very small, it
settles upon the surface of the wood and almost immediately
begins to clear away a place through which to burrow. There
is some controversy as to the method by which the burrow is
excavated, but it is quite certain that the foot assists the shell.
The details are not perfectly understood, but the facts are that
the hardest woods are penetrated and that surfaces are cut as
smoothly as though a sharp chisel had been employed.

Character of Excavation. — A shipworm is very small when it
enters a piece of wood, but once within develops rapidly and
then never leaves its burrow. The perforation through which
the shipworm enters is very small, but the diameter of the boring
increases rapidly, the average being reached at a point quite
near the perforation through which the shipworm entered. A
shipworm grows principally in length and must therefore tunnel
to secure space for the increasing length of its body.

The shipworm does not encroach upon other tunnels because
most of these tunnels are occupied by shipworms. It instinc-
tively avoids knots, imperfections, bark, cracks, and lines of
cleavage. Woods are not exempt from attack simply because
they are hard.

Wood may appear to be sound and yet be so weak that it can
be crushed by the hand. As much as fifty per cent, of the weight
of a piece may be removed without much evidence upon the out-
side. Failures often come suddenly and without warning. The
tops of piles thought to be in good condition are seen floating
away. A freight train on the Louisville and Nashville Railway

1 Reported to the writer by Messrs. Nesmith and Constantine of New York,
1897.

308

ORGANIC STRUCTURAL MATERIALS

crushed through a trestle that had been standing about ten
months and that had been frequently inspected.

Size of Borings. — The size of a boring depends upon that of the
shipworm that made it, and the size of the shipworm depends
upon its age and species. Five inches and as many feet may be
regarded as minimum and maximum lengths. One-quarter of

FIG. 55. — End of log of Panama mahogany destroyed in one season.

an inch is a small diameter from which measurements have been
made up to one and one-eighth inches.1 It is safer to disregard
minimum possibilities in such a connection.

Rapidity of Work. — Evidence upon this subject is seldom ac-
companied by statements of conditions under which the results
were accomplished, so it is sometimes hard to associate the boring

1 Measured by the writer in a specimen from the North Pacific Coast.

PLATE X. WORK OF SHIPWORM— LARGE BORINGS

The large circle near the top of the picture shows a boring actually
in. in diameter.

(Facing page 308.)

L

MARINE AND TERRESTRIAL WOODBORERS 309

with the species that made it. The species of the woodborer,
the location of the piece, the season, and the kind of wood in
which the boring exists are all important.

Conditions that influence the growth of the ship worm influence
the speed with which it works. Generally speaking, cold retards
while heat expedites the work of excavation. A six-inch burrow
may be driven in as many weeks so that a one-foot pile attacked
on all sides can be destroyed in that length of time. On the
contrary, other pieces remain practically intact for many years.

Wood has been found to contain shipworms after a submergence of
eight days (United States Annual Report of Scientific Discovery of
1857). Six-inch piles were destroyed at Aransas Pass in six weeks;
other piles in the same locality have lasted as long as three or four
months (Report, Chief of Engineers, U. S. A., 1888, pp. 13, 14). Piles
have been destroyed in one hundred days in Mobile Bay (Annual Report,
Chief of Engineers, U. S. A., 1879, p. 937) . Piles on the line of the Louis-
ville and Nashville Railroad sometimes have to be replaced after six
months service (Transactions, Am. Soc. C. E., Vol. XXXI, p. 221,
Montfort). Unpainted spar buoys have a life of about one year in the
vicinity of Cape Cod (Report to United States Fish Commission by
Captain Edwards). Piles have been destroyed in the harbor of Galves-
ton in three years (Report, Chief of Engineers, U. S. A., 1868, p. 512).
Piles have lasted as long as twelve years in the harbor formed by the
Delaware Breakwater (Annual Report, Chief of Engineers, U. S. A.,
1871, p. 667).

Field of Attack. — The fact that a shipworm lives upon micro-
scopic life present in sea water outside its burrow, makes it
necessary for its siphon extremities to be located at the entrance
to its burrow. This end of the shipworm being fixed as to posi-
tion, the wood is removed inward from the surface to a distance
measured by the increasing length of the shipworm.

The small portals to the burrows that are evident upon the
outside of the timber (see Plate IX) do not necessarily mark the
exact content of wood that is destroyed within; since, although
one end of the shipworm must remain at the entrance to its
burrow, the other can reach upward into the wood above the
water, or downward into that below the mud. Shipworms have
been known to work under pressures caused by twenty or twenty-
five feet of water.

Woods Subject to Attack. — Immunity is sometimes claimed
for some particular wood; but it is usually found that such a

310 ORGANIC STRUCTURAL MATERIALS

claim, based upon local conditions, is not generally substantiated.
It is safer to assume that all ordinary woods may be attacked by
these forms. Doubt may be felt with regard to some woods that
contain repellent gums, resins, or bitter essences, and some palms
that have open, porous structure; yet very few woods such as
these are used in American constructions.

Woods are not safe simply because they are hard. Osage
Orange, which is a very hard wood, has failed in several instances
where it has been used for piles. A Commission appointed in
Holland to investigate this question reported as follows:

"Although we do not know with any certainty whether among exotic
woods there may not be found those which resist the shipworm, we can
affirm that hardness is not an obstacle that prevents the mollusk from
perforating its galleries."

THE LIMNORIA (Limnoria lignorum). — -This isopod crusta-
cean, which has other names as
the wood flea, sand flea, gribble,
and boring gribble, is the prin-
cipal one of several similar
forms that attack woods when
in sea-water. The Limnoria is
much smaller than the shipworm,
FIG. 56.— The Limnoria. but it usually occurs in larger

numbers and in some localities
is almost equally destructive.

The Limnoria is found along the Atlantic Coast from Nova
Scotia to Florida. It exists sparingly in Long Island Sound; but
is abundant along the Coast of Massachusetts, and very destruc-
tive in the Bay of Fundy. It is also active in the north Pacific, as
in Puget Sound and the Straits of San Juan de Fuca. It is said
to exist upon the coast of Great Britain and in other European
waters.

Form and Physiology. — The Limnoria is about as large as a
grain of rice. The nearly straight sides are, in a general way,
parallel to one another, while the ends are rounded. The upper
and lower surfaces are flattened, the former being covered with
small hairs to which more or less dirt often adheres. The body
is made up of fourteen segments. To each of the seven segments
that follow the head is attached a pair of short, stout legs ter-
minating in claws, the shape of which suggests the small claws of
the lobster.

MARINE AND TERRESTRIAL WOODBORERS 311

The body of the Limnoria is grayish in color, and sometimes
resembles the color of the wet wood so much that it is difficult
to distinguish it. The Limnoria can swim, creep "backward and
forward, as well as jump backward by means of its tail. When
touched, it rolls itself into a ball, and in this particular, as well as
in general appearance, it resembles the common sow-bug.

The Limnoria differs from the ship worm in that quite certainly iib
is a vegetarian. The shipworm is sustained, at least for the most
part, by microscopic life drawn from the sea water, but the Lim-
noria devours wood. Its tunnel affords both food and shelter.

Influence of Temperature and Water. — Limnoria are plentiful
in some regions in the North where shipworms can exist but spar-
ingly because of the cold. Limnoria require pure sea water and
are seldom found in the comparatively fresh waters encountered
near the mouths of rivers.

Method of Attack. — Character of Excavation. — The Limnoria
attacks the wood by means of its mandibles or jaws. It prefers
wet wood and succeeds in making a very clean-cut excavation.

The work of the Limnoria differs from that of a shipworm in
that its tunnels terminate on the surface of the wood where they
can be plainly seen, whereas those of the shipworm are for the
most part concealed within the wood. The body of the shipworm
cannot emerge from the wood within which it has located, while
that of the Limnoria can pass freely in and out. The Limnoria
frequently works in conjunction with the shipworm. It attacks
the surface, while the shipworm takes away from the interior of
the woodwork.

The numberless, smooth, clean-cut galleries are close together
and the partitions that separate them are so thin that they can-
not long resist the action of the waves. Later, the partitions are
either washed away by the waves, or they decay. Fresh sur-
faces are then exposed and these are destroyed in the same man-
ner. Layer after layer is removed until the timber is destroyed.
The Limnoria can penetrate knots, but sometimes avoids them,
when such hard portions stand out in relief as the other parts are
destroyed.

Size of Borings. — The Limnoria is very small, but notwith-
standing this fact, it is very destructive. The multitude of these
woodborers compensates for their size. Each may be assumed
to be from one-sixth to one-fourth inch in length and about
one-sixteenth of an inch in diameter. The tunnels are about

312

ORGANIC STRUCTURAL MATERIALS

one-half of an inch in length and about one-tenth of an inch in
diameter.

Rapidity of Work. — The Limnoria does not work as rapidly as
the shipworm. The number of individual workers must in this

FIG- 57. — Knot showing surface from which work of Limnoria has been
removed by waves. (Reduced.)

case be taken as a measure of the rapidity of destruction. The
number of tunnels is more important than their depth. The
thickness of a piece of timber may be reduced from one-fourth of
an inch to as much as an inch in a year. Much wood used in
marine constructions is in the form of piles that are necessarily
exposed on all sides. The effective diameters of such pieces are,

PLATE XI. WORK OF THE LIMNORIA

MARINE AND TERRESTRIAL WOODBORERS 313

therefore, reduced twice as rapidly as indicated by the figures
noted.

Field of Attack. — The depredations of Limnoria are confined to
a limited distance above and below the low-water mark. Where
the variations of the tides are extensive, as in the vicinity of the
Bay of Fundy, the range of the Limnoria is correspondingly great.
It has been found, although rarely, at a depth of forty feet.

Woods Subject to Attack. — Most woods used by American con-
structors in waters where these forms are prevalent are subject to
attack by them.

THE CHELURA (Chelura terebrans). — It is of ten stated that the
Chelura is among the active enemies of woods; but efforts made
to discover work actually per-
formed by it have proved un-
fruitful, and it is not known
where this form exists as a
specimen and where it exists
as a real pest. It is probable FlQ. 53.— The Chelura.

that some results attributed

to the Chelura were actually caused by the Limnoria. The
Chelura is also known as the wood shrimp.

Form and Physiology. — The Chelura is an amphipod crusta-
cean. The form differs strikingly from that of the Limnoria,
except in size, and resembles that of the ordinary shrimp. The
body is semi-translucent and spotted or mottled with pink.
There are three pairs of caudal stylets, the last of which is nearly
as long as the body. The Chelura swims actively upon its back,
and, like the sand-hopper, can project itself to a considerable
distance when placed upon dry land. The Chelura resembles
the Limnoria in that it also is a vegetarian. Its burrow affords
both residence and food.

Method of Attack. Character of Excavation.— The work of
the Chelura and that of the Limnoria resemble one another in so
many particulars that the suspicion is warranted that the two
forms have been confused with one another. In both cases, the
wood is attacked from without, and numerous tunnels are driven
until the weakened layer succumbs to the action of the waves. A
new surface is exposed and this is eventually destroyed in the
same manner. The few specimens observed do not warrant wide
generalizations, but it is possible that the Chelura prefers the
ofter portion of the annual layer, and that the tunnels are

314 ORGANIC STRUCTURAL MATERIALS

curved, because these points were noticed in the few specimens
available.

Size of Borings. — The Chelura is somewhat larger than the
Limnoria. The specimens seen were about one-third of an
inch in length. The burrows were a little larger than those of the
Limnoria.

Field of Attack. — The specimens observed were found at Prov-
incetown, in wood located about ten feet below the low-water level.
MISCELLANEOUS. Fresh-water Woodborers.— The work
of a fresh-water woodborer (Sphceroma destructor Richardson)
in trestles of the Florida East Coast Railway resembles the work
of the Limnoria, save that the burrows of the fresh-water borer
are larger than those of the Limnoria. A yellow pine pile was
reduced by them from a diameter of sixteen inches to one of seven
and one-half inches in eight years.1 Several kinds of fresh-
water woodborers, some of them very large, have been found in
Australian rivers.2

Barnacles (Lepas antifera). — Barnacles do not injure wood.
On the contrary, they protect such parts as are
covered by them from the attacks of marine
woodborers. Barnacles attach themselves, singly
or in clusters, to floating or submerged wood-work
and are disliked by ship owners because bottoms
covered in such a manner cannot move as rapidly
through the water.

Stone-borers. — Stone-borers are interesting be-
cause they show the power of forms that are
apparently feeble. The pholas or piddock (Pholas
dactylus) is a typical species of the molluscan
family Pholadidse, which includes other stone-
borers as well. The pholas bores in stone by
59 so as to " tne

Barnacle(Le-

pas antifera re- excavation. The long foot or pestle, similar to

" that of the teredo> is then thrust out and rubbed
against the stone. The process is assisted by
particles of sand or rock.3

1 See report by Harriet Richardson (Biological Society, Washington,
May 13, 1897).

2 Correspondence Professor Charles Hedley, Sydney, Australia.

3A cargo of marble wrecked in the North Atlantic was destroyed in one
year by a boring sponge (Cliona sulfurea Vcrrill). The shells of live
oysters are often attacked.

PLATE XII. WORK OF THE CHELURA

V

bJO

E

o

-fj

bfi

fl

1

a

I

o

—

I

£

|

-M
o

£

MARINE AND TERRESTRIAL WOODBORERS 315

FIG. 60. — Stoneborer in sandstone. (Life size.)

PROTECTION FROM MARINE WOODBORERS

Many of the attempts made to protect woods from the attacks of
marine woodborers have failed, but some have succeeded. The
methods usually considered are as follows:

Removal During the Breeding Season. — This method, which
may be used to protect such objects as buoys, bathing houses,
and rowboats, is applicable only where the breeding season is
short, as in the North.

Change of Water. — Wooden vessels attacked by sea wood-
borers are sometimes hauled into fresh or muddy waters. In
the past several attempts have been made to protect special
woodwork by surrounding it with fresh water.

Use of Selected Woods. — The few woods for which claims have
been made are not generally employed in construction, and it is
not urged that any one of these woods is always exempt. Thus
far evidence favors palm and palmetto, probably because these
woods have loose, open structures.

External Coatings. — This form of treatment is good because
applications can be limited to the parts of timbers exposed to
attack. The parts much above the high-water mark and those
much below the mud line do not have to be protected. External
coatings are defective in that they ultimately succumb to blows
from waves, ships, and other floating objects.

(a) The bark sometimes left upon logs protects them as long
as the bark remains intact. This is explained by the reluctance of
shipworms to cross seams. The bark is soon loosened and re-
moved by the waves,

316 ORGANIC STRUCTURAL MA TE RIALS

(6) Planks joined closely over the surface of woodwork will
protect it from ship worms as long as the planks remain.

(c) Copper and other metals have been used to enclose piles
as well as the bottoms of wooden vessels. These coatings are
expensive but do protect against all forms of marine woodborers
as long as they remain intact.

(d) Teredo-nails or worm-nails, said to have originated with
the Romans, resemble ordinary carpet, upholstery, anc( thumb
tacks, in that they have short spikes and large, flat heads. These
nails are driven close together until the wood is enclosed by the
heads. Experiments with teredo-nails have been made by the
New York Department of Docks.1

(e) Paraffin, tar, asphalt, paints, and other mixtures have been
used to protect woods from marine woodborers, but usually do
not remain long in place, since the coatings that are not softened
by the water are likely to be removed by erosion. This form of
protection should be frequently inspected.

(/) Coatings are sometimes reinforced by wire net or by burlap.
A paraffin mixture reinforced by burlap has been used to protect
piles by the California State Board of Harbor Commissioners,
the Northern Pacific Railway, and the Great Northern Railway.

The bark was removed and the surface of the pile covered with a mix-
ture of powdered limestone, clay, and paraffin. It was then wrapped
in burlap; another coat of the compound was applied and wooden battens
were nailed up and down to keep the coatings in place.2

(g) Portland-cement mortar has been applied to piles after
they had been driven. This is a good method in that the cement
can be limited to the parts that are in danger; but it has not
proved adequate because the cement being comparatively brittle
is in danger of being cracked and destroyed. The cement is
applied in several ways. Piles are sometimes encircled by sewer
pipes, the spaces between the pipes and piles being filled with
cement. Sometimes iron moulds, which are removed as soon as
the cement is set, are employed.3

1 See "Transactions American Society of Civil Engineers" (Vol. XXXI,
p. 235). The " Dutch Waterstaat" specifies that nails must be well forged
and not brittle. Diameters must be 3 cm. and lengths must be 4 cm. One
kilogram must contain from thirty to thirty-four nails.

2 "Engineering News," February 8, 1894.

3 The Louisville and Nashville Railroad treated four thousand piles in this
way, at an average cost of $1.25 per foot of length (Transactions American
Society of Civil Engineers, Vol. XXXI, p. 225),

MARINE AND TERRESTRIAL WOODBORERS

317

(h) Piles are also enclosed by sand. Sewer pipes are used and
the spaces between pipes and piles are filled with sand instead of
cement. The cost is less than for cement, while imperfections,
serious enough to permit the sand to escape, are revealed by the
settlement of the sand at the top. Piles treated in this manner
are said to have been sound after twenty years of service.1

FIG. 61. — Piles protected by pipes and sand. 2

(i) Protection is sometimes afforded naturally by oysters,
barnacles, and other forms.

Preservatives Applied Within Woods. — Of the many mixtures
that have been used to repel the attacks of marine woodborers,
creosote alone deserves attention. Experience has shown that
sufficient quantities of good coal-tar creosote, well applied to

1 Transactions American Society Civil Engineers, Vol. XXXI, p. 221.

2 Photograph by Lockjoint Pipe Company.

318 ORGANIC STRUCTURAL MATERIALS

appropriate woods, will protect the woods from marine wood-
borers during terms that may be measured by the durability of
the creosote. Creosoted piles have stood against the attacks of /,
shipworms for as long as forty years. The failures that have
taken place were, in almost every case, due to poor or insufficient , T
creosote, or to poor methods of application. V ~J\&&+^£t \yLk~Jubve
Substitution. — Substitution is not protection, but, in this /
connection, it is well to remember that other materials can often
be used in place of wood. If iron had not so largely replaced
wood in marine constructions, sea woodborers would require
more attention than they now receive.

TERRESTRIAL WOODBORERS

The total losses caused by terrestrial woodborers are enor-
mous. Many trees are completely destroyed by them. But,
as distinct from trees, woods in construction do not suffer unduly
from these pests. The losses in this direction are less than from
fire or from rot.

If plant products, growing and in storage, be included with live stock,
the losses due to depredations of insects in general would compare with
the yearly expenditures of the National Government. It has been esti-
mated that the total injury to agricultural products in the United States
by insects amounts to $700,000,000. annually.1

Terrestrial woodborers are too numerous for any save the most
general notice. Most of them are insects, and it is, therefore, well
to remember that all insects are grouped according to the way in
which they develop from the egg to the adult. First, some
insects develop with what is known as complete metamorphosis;
second, others develop with incomplete metamorphosis; and
third, still others develop without any metamorphosis.

In the first case the egg liberates the larva, sometimes popularly
known as "worm," which changes to the pupa, which in turn
changes to the adult or imago. The Colorado potato beetle is an
example. The egg, the thick larva, the pupa, and the adult
beetle may often be observed upon a single potato plant. In the
second case the egg liberates a form that closely resembles
the adult, and this form, known as the nymph, changes directly

1 Marlatt (United States Department of Agriculture Year Book, 1904,
p. 461); also "Insect Injuries of Forest Products," Hopkins (United States
Department of Agriculture Year Book, 1904, p. 381) ; " Guide to the Study of
Insects," Packard.

PLATE XIII. WORK OF LARV.E OF BEETLES— " BOOK WORMS"

Corner of Book Cover, Tarry town, New York. Perforations Reduced

One-half.

Whitewood Bureau Drawer-Bottom, New York City. Life Size.

Yellow Pine Base-Board, New York City. Life Size.

(Facing page 318.)

MARINE AND TERRESTRIAL WOODBORERS 319

to the adult. The locust is one of the forms that develop with
incomplete metamorphosis; the nymph of the locust is like the
adult, save that it has no wings. In the third case, the egg
liberates a form that resembles the adult in practically all re-
spects save size. Development without metamorphosis takes
place in but a single order of insects (Thysanura). The bristle-
tails are examples.

Some insect woodborers attack the bark or wood of living trees
while others are associated with woods that are ready for, or
already in, construction. Some prefer sound and healthy woods,
and others prefer those that are moist and decayed. Some insects
are particularly associated with certain species of trees, and
among these are groups known as hickory borers, elm borers, and
the like. There are several hundred insect enemies of oak alone.
BEETLES (Order Coleoptera). — Beetles form what is known to
naturalists as an Order.1 This one includes
almost one hundred thousand species; besides
which, others are frequently discovered.
Beetles undergo a complete metamorphosis.
The larvae are sometimes called grubs.
Beetles have two horny sheaths or wing-
covers that meet in a straight line down
the back over a single pair of wings. Their
mouths are formed for biting, and are some-
times so powerful as to be able to make an
impression upon soft metal. Most wood-
boring beetles attack live trees, but some at-
tack woods in construction. Most of those tion^in sheet-lead
that attack woods do so while they are in the roof made by adult
larval condition, but some are harmful after
they have become adults. It is common to refer to all
woods that have been injured by beetles and other insects as
" worm-eaten woods," even although the adult, as distinct from
the larva, was responsible for the borings noticed.

The family Scolytidse includes many forms that attack trees.
Some bore in twigs and are known as "twig beetles," others bore
in roots and are known as "root beetles," and still others attack
bark and are known as "bark beetles." Some members of this
family cut symmetrical grooves upon the outer surfaces of the

1 The animal kingdom is divided into Phyla, Classes, Orders, Families,
Genera, Species, and Individuals, the importance being in the order named.

320 ORGANIC STRUCTURAL MATERIALS

sapwood of trees and are known as "engraver beetles." The
powder-post beetles include many enemies of seasoned woods that
attack house-trim, flooring, spokes, tool handles, and the like.

The larvae of some beetles attack the paste, covers, and leaves of
books as well as woodwork, and are often known as "book-
worms." The worm-eaten appearance of furniture is often due
to them. An instance is on record of a bedpost destroyed thus in
three years. The name bookworm is not confined to any par-
ticular species but applies to any form of insect life that attacks
the covers, leaves, or paste of books.1

Summary. — Although very numerous, beetles are principally
harmful to living trees, and for this reason protective measures are
almost wholly in the hands of growers, foresters, and horticul-
turists. The total amount of wood in construction that is injured
by beetles is comparatively small. Engineers seldom attempt
to protect woods from the attacks of beetles.2

MOTHS AND BUTTERFLIES (Order Lepidoptera) .—Moths
and butterflies undergo complete metamorphosis. Both forms
possess four membranous, scaly wings, and in both cases the
larva are often known as caterpillars. Butterflies fly by day,
while moths fly by night, and there are also differences in the ways
in which the wings are folded. Adult moths and butterflies do
not attack trees or woods in construction, but the larvae of some
species of both are very destructive. With few exceptions, liv-
ing trees, as distinct from woods in construction, suffer from their
attacks.

The Gypsy Moth (Porthetriadispar).3 — The destruction accom-
plished by the larvae of this species, by their habit of feeding on

1 The silver fish (Lepisima saccharina] often attacks paper.

2 " Insects Injurious to Forest Products," Hopkins (United States Depart-
ment of Agriculture Year Book, 1904, pp. 387-388); "A Revision of the
Powder-Post Beetles of the Family Lyctidae," Kraus and Hopkins (United
States Bureau of Entomology, Technical Series No. 20, Part 3, 1911);
"Principal Household Insects," Howard and Marlatt (United States Divi-
sion of Entomology, Bulletin No. 4, pp. 76-78); etc., etc.

3 See also "The Gypsy Moth," Forbush and Fernald (Massachusetts State
Board of Agriculture, 1896); "Report on the Field Work against the Gypsy
Moth and the Brown-Tail Moth," Rogers and Burgess (United States
Bureau of Entomology, Bulletin No. 87, 1910); "Insects Affecting Park and
Woodland Trees" (New York State Museum, Vol. I, pp. 79-84); "The
Importation into the United States of the Parasites of the Gypsy Moth and
Brown-Tail Moth," Howard and Fiske (United States Bureau of Ento-
mology, Bulletin No. 91, 1911); etc., etc.

MARINE AND TERRESTRIAL WOODBORERS

321

leaves, has been so great that, in Europe, it has been referred to as
"the plague," and, in the past, it has been thought to be a scourge
sent by the Almighty as a penalty for wrong-doing. The Gypsy
Moth was brought to the United States in 1868, but remained
unrecognized until 1889. The work of the National Government
and of the different States in combating this pest has produced
encouraging results.

The Goat Moth (Cossus ligmperda). — The young, which are
said to remain in a larval condition for as long as three years,
possess wedge-shaped heads with large, trenchant jaws, equipped
with powerful muscles that enable them to cut into very hard
woods. The Carpenter Worm is the larva of a beautiful gray
moth (Prionoxystus robinice) with wings
that spread over a distance of about
three inches. The full grown larva, which
is about two and one-half inches long,
sometimes bores into trunks of oaks, ma-
ples, and locusts to such an extent that
such woods have very little value later.

Summary. — The larvae of moths and
butterflies are among the most dreaded
insect enemies of living trees. Woods in
construction are seldom injured. Pro-
tective measures are in the hands of for-
esters and horticulturists.1

TERMITES (Order Isoptera) .—Ter-
mites are called " white ants" because
they are of a dingy, white color, and be-
cause they live in communities as true
ants do. Termites have thick waists and

develop with incomplete metamorphosis, ™ite(Termesbellicosus).

. * ' (Natural size.)

whereas true ants have slender waists and

develop with complete metamorphosis. The mouths of ter-
mites are formed for biting. The American termite (Termes

1 See also "The Gypsy Moth," Forbush and Fernald (Massachusetts State
Board of Agriculture, 1896); "Report on the Field Work against the Gypsy
Moth and the Brown-Tail Moth," Rogers and Burgess (United States
Bureau of Entomology, Bulletin No. 87, 1910); "Insects Affecting Park and
Woodland Trees" (New York State Museum, Vol. 1, pp. 79-84); "The
Importation into the United States of the Parasites of the Gypsy Moth
and Brown-Tail Moth," Howard and Fiske (United States Bureau of Ento-
mology, Bulletin No. 91, 1911); etc., etc.

FIG. 63.— Queen ter-

322 ORGANIC STRUCTURAL MATERIALS

flavipes), the European termite (Termes lucifugus), and the
African termite (Termes bellicosus) are important species.

Termites are encountered in the Northern States in hot-house
plants, dead stumps, and under stones. They have destroyed
live trees as far north as in the vicinity of Boston, but are more
plentiful in the Southern States, and are very destructive in the
tropics, where they occupy a position among land woodborers
that compares with that held by shipworms among marine wood-
borers. Although termites sometimes attack live plants they
seem to prefer tissues within which life processes have ceased,
and house timbers, railway ties, and other structural pieces, as
well as dead stumps, books, and papers, are subject to attack by
them.

A floor in the National Museum at Washington was undermined sev-
eral times by a colony of termites that could not be located, until it
became necessary to replace the floor by one of cement. Termites have
destroyed frame buildings in Washington and Baltimore. A school
library in North Carolina was destroyed during the summer vacation.
Humboldt explains the rarity of old books in Spain by the fact that
termites are so active in that country.

It is seldom urged that any wood is always exempt from the
attacks of termites; but some, such as teak and redwood, seem to
be more fortunate than others in this respect. Railway ties are
not often attacked by termites, not because of the kinds of wood
that are used but because of the disturbance caused by passing
trains. Redwood stave pipes have resisted termites and other
insects in the United States as long as the pipes remained wet.

Some methods employed to protect woods from termites are as
follows: (a) Decayed wood that is likely to attract or shelter
colonies of termites, should be removed. (6) When discovered,
colonies of termites should be destroyed by the liberal use of
steam, hot water, kerosene, or other agencies, (c) Saturation
with good coal-tar creosote has preserved timbers from attack.

REFERENCES. — "Dangers from White Ants," Hagen (American Natural-
ist, July, 1876, pp. 401-410); "Manual," Comstock (pp. 95-97); "Insects
Injurious to Forest Products," Hopkins (United States Department of
Agriculture, Year Book, 1904, p. 389); "Important Philippine Woods,"
Ahern (p. 91); "Principal Household Insects," Howard and Marlatt (United
States Division of Entomology, Bulletin No. 4, pp. 70-76); "The White
Ant," Marlatt (United States Division of Entomology, Circular No. 50,
Second Series).

PLATE XIV. WORK OF LARGE CARPENTER ANT

•* ' * - •'••

(a) Pine Shingle from House on Long Island.

(6) Fence Post from New York City.

(Facing page 322.)

MARINE AND TERRESTRIAL WOODBORERS

323

(d) As far as possible endangered structures should be surrounded
by cleared spaces, and these should be covered with asphalt or
gravel, (e) In the tropics, tables and other kinds of furniture are
sometimes protected by placing the legs in small vessels contain-
ing oil. (/) Books and papers endangered by termites should be
frequently inspected, (g) It is often best to replace woodwork
with stone or metal.

FIG. 64. — Termites (Termes flavipes). Queen, nymph of winged femaley
worker, and soldier. (Enlarged.) Marlatt (U. 8. Division of Entomology,
Circular No. 50).

Summary. — Adult termites are the principal terrestrial wood-
borers that attack woods in construction. Termites are occasion-
ally active in the North, but are often exceedingly active in the
tropics and semi-tropics. It is safest to replace wood by iron or
stone wherever termites are known to be unduly active.

THE CARPENTER-BEE (Xylocopavirginica). — The carpenter-
bee, which resembles the ordinary bumble-bee in size and appear-
ance, is equipped with powerful jaws, and often attacks telegraph
poles, fence posts, and house timbers. The tunnels thus formed
may be one foot or more in length, and are used by the bees as
nesting places. Some wasps attack wood.

THE LARGE CARPENTER ANT (Camponotus herculeanus
pennsylvanicus) . — As distinct from the termite this is a true ant,
and like other ants -it develops with complete metamorphosis. It
seldom attacks sound trees, but does often attack some of those

324

ORGANIC STRUCTURAL MATERIALS

that have been wounded or are diseased, and also, sometimes,
attacks woods in construction. McCook states that carpenter
ants were responsible for "at least one accident" that occurred
in connection with the wooden trestle bridges formerly used by
the Pennsylvania Railroad Company.1

Ants offer one of the most perfect illustrations of communistic society.
The State declares war, provides food, cares for the children, and owns
all the property. Patriotism, loyalty, courage, and never-failing indus-
try are exhibited. War, pillage,
slavery, and disregard for the
rights of other communities pre-
vail. There are many species of
ants, and each one is character-
ized by some peculiarity. Some
are road builders; others live in
large mounds; and some bore in
decayed trees . Most ants tunnel .

METHODS OF PROTECTION

Injury from insects can-
not be completely controlled.
Man has not yet succeeded
in eliminating a single species
of insects. But as distinct
from this, the enormous losses
that now result from this cause
would be greater than they
are if man had remained in-
active.

It is estimated that losses due
to the Hessian fly have been re-
duced over $100,000,000 annually, and also that the rotation of corn with
oats and other crops has reduced the damage done by root worms to the
corn crop of the Mississippi Valley about $100,000,000 annually.
$15,000,000 to $20,000,000 are saved annually by protecting apple
trees from insects by means of sprays.

Defensive practice is almost wholly in the hands of foresters
and horticulturists and is directed toward the protection of trees.
Engineers seldom attempt to protect woodwork from insects other
than termites, and the methods used to protect wood from these

FIG. 65. Tunnel of carpenter-bee in
yellow-pine grape-arbor post, New
York City.

1 ''Nature's Craftsman," McCook (pp. 126, 127).

PLATE XV. HIGH POWER SPRAYING APPARATUS IN ACTION

From "Report of Field Work against Gypsy Moth and Brown-Tail Moth," Rogers &
Burgess (United States Bureau of Entomology, Bulletin 87).

(Facing page 324.)

MARINE AND TERRESTRIAL WOODBORERS 325

insects resemble those used to protect it from marine woodborers
and from rot. The value of birds as defensive agents against
insects is beyond estimate. When birds are destroyed insects
increase proportionately. This value of birds in maintaining
the balance set by nature should be recognized by all. Some
insects that prey upon other insects should be noted also. Some
of these helpful insects directly destroy those that are harmful,
while others destroy the harmful insects indirectly by depositing
their eggs on, or in their bodies. These predaceous and parasitic
insects are natural agents of great value in insect control.

CHAPTER XIII
PROTECTIVE METHODS — SEASONING

The term seasoning refers to certain processes designed to re-
move water from woods. Woods dry, shrink, and otherwise
improve by these processes.

Improvement Caused by Drying. — The influence of moisture
upon wood has already been considered.1 Dry wood is stronger
than green wood and much less liable to decay. All woods should
be shrunk before they are finally placed in position.

Improvement Caused by Alteration. — Experience shows that
other changes take place when woods are seasoned. Von
Schrenk believes that albuminous substances, and possibly
tannin, resins, and other incrusting materials are altered or
recombined during these processes.2 The reasons are not clear,
but the facts are that additional changes do take place and that
they are of such a nature as to suggest the changes that take
place in fruits when they are " cured."

It is often hard to season wood without injuring it somewhat.
This is because of (1) irregularities that exist in the arrangement
of the wood-elements, and (2) irregularities that exist in the dis-
tribution of the moisture; as, for example, the difference in the
amount of moisture in the sapwood and in the heartwood of a
green log. It is easy to dry wood, but it is not always easy to dry
it so that every part will shrink together. All methods are not

1 See Index.

2 "Seasoning of Timber" (United States Bureau of Forestry, Bulletin No.
41, p. 9).

REFERENCES. — "Timber," Roth (United States Division of Forestry,
Bulletin No. 10, 1895); " Seasoning of Timber," von Schrenk (United
States Bureau of Forestry, Bulletin No. 41, 1903); "Kim-Drying Hardwood
Lumber," Dunlap (United States Forest Service, Circular No. 48, 1906);
"Principles of Drying Lumber at Atmospheric Pressure," Tiemann (United
States Forest Service, Bulletin No. 104, 1912). See also catalogues of the
B. F. Sturtevant Company, the Morton Dry Kiln Company, the Standard
Dry Kiln Company, the American Blower Company, etc. "The Theory of
Drying, etc.," Tiemann (United States Department of Agriculture, Bulletin
No. 509, March, 1917). i(

326

PRESERVATION OF WOOD— SEASONING

327

suitable for all woods. Judgment and experience are required to
select the proper method in any particular case.

Three groups of processes are employed to season woods.
They are natural-seasoning, water-seasoning, and kiln-seasoning.

NATURAL SEASONING. — Just as certain fruits will either
cure or rot, according to the
way in which they are exposed
to the weather, so, also, will
certain woods. When woods
are exposed under certain
conditions in the open air,
water is expelled and the
changes that have been de-
scribed take place.

The details of exposure are
important. A few woods do

FIG. 66.— Close-piling. This en-
courages rot.

well under almost all con-
ditions, but the rule is that
close piling and contact with the ground encourage rot. Tim-
bers should be raised from the ground and should be so piled
that the air can circulate between them and they should re-

main in these positions during
intervals that depend upon
their shapes and sizes.

While it is often assumed
that the best results are those
obtained from natural sea-
soning, it should be remem-
bered that the best results
are not invariably thus ob-
tained. The pieces within a
pile may be well seasoned,

FIG. 67.-

permits

and checked from having
dried too rapidly. From two to four years must often pass be-
fore woods are completely dried by the natural method. It is
expensive to hold stock so long, and it is dangerous because of
fires. However, wood is normally improved, even although
the process is not carried through to the end.

The extreme form of natural seasoning is practiced with
pieces intended for musical and mathematical instruments, and

328 ORGANIC STRUCTURAL MATERIALS

wood engravings. On the other hand, most railway ties and
other large construction pieces receive a minimum of attention.
It seldom happens that these large pieces are completely sea-
soned; but the improvement that takes place while they are
piled waiting for use is ordinarily very great, and, with this in
view, such pieces should be piled loosely so that the air can cir-
culate between them.

Natural seasoning requires so much time that it is usually
combined with some other method. Before woods are thus
seasoned they are often soaked in water; and sometimes drying
commenced by this method is completed in a kiln. Natural
seasoning, air seasoning, and yard-drying mean the same.

WATER SEASONING. — Logs are often stored under water.
The tendency to crack that exists when they are exposed to the
hot sun, and the danger from insects and from rot, are counter-
acted as long as they remain thus submerged.

Woods keep safely under water, and, at the same time, undergo
changes that render them more durable after they have been
removed from the water. They dry rapidly when brought again
into contact with the air, and are then durable in proportion as
they have been washed by the water. Water seasoning is
usually combined with natural seasoning.

The water acts, first by excluding the air, and second by leach-
ing out impurities. There is no reason why wood should ever
decay while it remains under water. The softening or physical
disintegration that may eventually take place is not decay.
Logs are sometimes found buried deep in the mud of swamps.
Pieces cut from such logs are often particularly prized because
in the course of immersion they have been so thoroughly cleansed
and rendered durable, and also because they have lost much of the
natural tendency to warp.

KILN SEASONING. — Kiln seasoning originated with at-
tempts to prevent warping and checking in special pieces. In the
United States, nearly all hardwoods, save those in large con-
struction pieces, are now cured by this method. Drying pro-
ceeds rapidly and details can be controlled in kilns as they cannot
be in natural-seasoning or in water-seasoning.

There are many details and combinations, but the factors that
influence design and operation in all cases are temperature, mois-
ture, and circulation.

PRESERVATION OF WOOD— SEASONING 329

Temperature— Heat may be dry or wet. In both cases, high tem-
peratures should be avoided. Dry heat in excess of two hundred and
twelve degrees is sufficient to expel some of the volatile constituents of
the wood, which then becomes weak and brittle. The equivalent of
this temperature in moist heat is not known. Temperatures of from
one hundred degrees to one hundred and twenty degrees Fahrenheit
are used in connection with green oak and some other difficult woods,
while temperatures of from one hundred and sixty degrees to one hun-
dred and eighty degrees Fahrenheit are employed with pine and cedar.

The temperature of the entire charge must be raised to a point at
which the drying is to take place. The surface of wood heated in warm,
dry air is liable to shrink before the heat has penetrated and acted upon

FIG. 68. — A kiln for drying wood.

the moisture that is within. Wet heat or steam adds to the moisture
but assists because it keeps the surface soft and swollen until the heat
has penetrated to the interior.

Moisture. — Natural moisture or sap must be distinguished from
moisture that may be absorbed after the tree has been cut down. Most
of the natural moisture is in the outer sapwood and this moisture is
often retained, or even added to, with advantage, so that the outer wood
will not shrink before the heat has penetrated to the moisture further in.
This is particularly necessary in the case of oaks and other woods char-
acterized by complex cellular arrangements.

Ability to season woods successfully in kilns depends upon ability
to manipulate the moisture. Heat, circulation, and the kilns themselves
are designed or directed with this end in view. Some processes include
the addition of steam while others use only the moisture that has been
evaporated from the wood. In other processes the moisture from the
wood is removed by condensation upon the surfaces of pipes filled with
cold water. Moisture is sometimes introduced by piling snow upon
the lumber as it enters the "greenwood ends" of the kilns. Pieces
must be piled so as to facilitate the escape of the moisture.

Circulation. — The air within a kiln does not remain motionless. On
the contrary, it moves naturally because of the heat, or else the move-
ment is induced by means of fans, and, in both cases, drying may be

330

ORGANIC STRUCTURAL MATERIALS

hastened or retarded by hastening or retarding the circulation of the
air currents. Air currents may pass in at the bottom and out through
the sides of the kilns, or they may pass through the kilns from one end
to the other.

Forms of Kilns. — The principal features of all kilns are (1)
the drying chambers in which the wood is stored,1 (2) the fur-
naces for heating air or making steam, and (3) the devices for
causing the air to circulate within the drying chambers.

There are kilns within which charges remain stationary, and
others within which charges move through from end to end.

FIG. 69. — Interior of a drying chamber.

When the wood remains stationary, in what is known as a " charge
kiln" or " apartment-kiln," the moisture in the air is removed
little by little, and the mass is finally exposed to a current of
warm, dry air. When the charge moves forward, in what is
known as a " progressive-kiln/' it advances through an air-
current that contains most moisture near the entrance or "green-
wood end" and least moisture at the other extremity where the
wood emerges.

Kilns are also grouped according to the origin of the draft,
which may be natural, if caused by pipes or radiators placed
beneath the drying chambers; or it may be forced if the draft,
heated outside the kiln, is forced in by a fan. As stated already,

1 Drying chambers are from fifteen feet to one hundred and fifty feet in
length and from ten feet to thirty feet in width. They are usually built of
wood, but may be built of brick, or of concrete, as shown in the preceding
picture.

PRESERVATION OF WOOD— SEASONING

331

the air currents may pass in at the bottom and out through the
sides of the kilns, or they may pass through from end to end.

Kilns designed for natural draft are often known as "moist-
air kilns," and those designed for forced draft as " hot-blast
kilns," but these names refer to details of operation, rather than

-t-r

FIG. 70. — A scheme for a radiator kiln.

to methods of construction, since moist air may be used
in kilns of either kind, regardless of the source of the draft.

FIG. 71. — A scheme for a blower kiln.

Natural-draft kilns and forced-draft kilns are also sometimes
referred to as " radiator-kilns" and " blower-kilns " respectively.

A scheme for a radiator or moist-air kiln designed for progressive
operation is shown in the picture. The pieces that are to be seasoned
are arranged upon trucks, which are then rolled into the kiln until it is

332 ORGANIC STRUCTURAL MATERIALS

full. After a sufficient time in the kiln, one truck with its charge is
removed from the " dry-wood end," the others are moved forward, and
a new charge is admitted at the "greenwood end" of the kiln. The
ventilator shaft at the right is often dispensed with. The general direc-
tion followed by the air currents is shown by the arrows.

A scheme for a blower-kiln is also shown. The humidity is main-
tained by using the same air repeatedly. The saturated air drawn
from the "greenwood end" at the left of the picture, deposits part of
the moisture upon the cold water coils located at the left of the fan,
The air then passes on through the fan and is re-heated by the steam
pipes toward the right. The air is relatively dry and warm as it re-enters
the dry end of the kiln.1

Operation. — The several parts of the process employed within
a kiln of any kind may be grouped as they relate (1) to prepara-
tion and (2) to drying. First, the temperature of the charge
must be raised to the point at which the drying is to take place,
while the surfaces of the pieces that make up the charge remain
or are rendered soft and permeable. Second, the drying is
forced by means of the draft, but at such a rate that the moisture
from within the pieces can move out fast enough to replace the
moisture that escapes from their surfaces.

Preparation. — The charge or apartment kiln both prepares and then
dries the wood before it is removed. Once within this kiln the wood is
not removed until the process is completed. In the progressive system
the wood is sometimes, but not always, prepared before it is admitted
to the drying chamber. The auxiliary kiln, that is here sometimes used,
should be placed as near as possible to the greenwood end of the prin-
cipal kiln so that the charge will not be unduly chilled during transfer.

Drying. — The draft must be held back until the heat has penetrated
within the pieces. Even then, it must not be forced unduly, or the
surface moisture will escape too rapidly, and cause the surface wood to
shrink before that inside has had time to dry. Case-hardening, honey-
combing, checking, warping, or twisting may then result.

Difficulties. — In kilns, where drying is hastened, the difficulties
that have been mentioned in connection with slower methods of
seasoning become more pronounced. The situation has been
expressed as follows :2

"In drying chemicals or fabrics, all that is required is to provide heat
enough to vaporize the moisture and circulation enough to carry off the

\From United States Forest Service; Circular No. 48.
2 "Kiln-Drying Hardwood Lumber," Dunlap (United States Forest Serv-
ice, Circular No. 48, p. 5.).

PRESERVATION OF WOOD— SEASONING 333

vapor, and the quickest and most convenient means to these ends may
be used. In drying wood, whether in the form of standard stock or
finished product, the application of the requisite heat and circulation
must be carefully regulated throughout the entire process, or warping
and checking are almost certain to result. Moreover, wood of different
shapes and thicknesses is very often differently affected by the same
treatment. Finally, the tissues composing the wood, which vary in
form and physical properties and which cross each other in regular
directions, exert their own peculiar influence upon its behavior during
drying. With our native woods, for instance, summer wood and spring

FIG. 72. — Auxiliary kiln for preliminary treatment.

wood show distinct tendencies in drying, and the same is true in less
degree of heartwood as contrasted with sapwood. Or, again, pro-
nounced medullary rays further complicate the drying problem. Plain
oak and quartered oak require different treatment. Even in mahogany
and similar tropical woods, which are outwardly more homogeneous,
various kinds of tissues are differentiated."

The presence of knots, windshakes, frostshakes, and other
defects add to the problem, which is to dry without distortion
rather than simply to dry. The comparatively simple cellular
structure of coniferous woods makes it easier to dry the woods of
that series. The broadleaf woods as a group are more difficult,
and some of them, such as the oaks, are particularly hard to dry.

334 ORGANIC STRUCTURAL MATERIALS

Time Required. — The time required to kiln-season lumber
depends upon the sizes, shapes, and species of the individual
pieces. Some operators dry one-inch white oak planks in four
or five days, while others require one or two weeks for the same
woods, and still others need twice as long. Plain oak and
mahogany dry with about the same speed; these woods require
less time than quartered oak, and longer than ash, birch, and
basswood.

PROTECTION OF SEASONED WOODS.— Dry woods
should remain dry. Woods suffer if their cell structures expand
and contract too frequently. The cell structures may remain
healthy, but they separate more easily from one another, and
eventually the piece as a whole is weakened. The influence of
moisture upon the fungi that cause disease will be remembered.
Seasoned woods that are to be exposed to the weather should be
protected by coatings applied to their surfaces, or by antiseptics
introduced within them.

CHAPTER XIV

PROTECTIVE METHODS — INTERNAL TREATMENT
PRESERVATIVE COMPOUNDS APPLIED WITHIN WOODS

Preservative compounds are applied within woods to produce
results of several kinds. Sometimes, the object is to increase
resistance to decay; sometimes, it is to repel the attacks of
teredos and other live woodborers, and sometimes, the object
is to retard fires. Preservatives within woods remain where
paints on the outside would soften or be rubbed away. Paints
would fail if applied to woods used in marine positions or in rail-
way ties, whereas preservatives injected within woods have suc-
ceeded in such positions.

Preservative chemicals were first applied within woods in
England. The diminished supply of wood, and the early rotting
of their wooden ships, caused the English to practice within this
field more than one hundred years ago. The beginning of real
activity, however, was connected with the development of rail-
ways (1830-1840).

REFERENCES. — "Antiseptic Treatment of Timber," Boulton (Proceedings
Institution of Civil Engineers, London, 1884); "The Preservation of Tim-
ber," Report of Committee (Transactions American Society of Civil Engi-
neers, 1885); "Wood Preservation," Flad (United States Forest Service,
Bulletin No. 1, 1887); "Preservation of Railroad Ties," Curtis (Transactions
American Society of Civil Engineers, Vol. XLII, 1899); "Proposed Method
of Preservation of Timber with Discussion," Kummer (Transactions Ameri-
can Society of Civil Engineers, Vol. XLIV, 1900); "Hand-book of Timber
Preservation," Samuel M.Rowe (Author's Edition, 1900); "Preservation of
Railway Ties in Europe," Chanute (Transactions American Society of Civil
Engineers, Vol. XLV, 1901); "Timber Tests and Discussions" (Transactions
American Society of Civil Engineers, Vol. LI, 1903) ; " Decay of Timber," von
Schrenk (United States Bureau of Plant Industry, Bulletin No. 14); "Recent
Progress in Timber Preservation," von Schrenk (United States Department
of Agriculture, Yearbook, 1903); "The Inspection of Treatment for the
Protection of Timber by the Injection of Creosote Oil," Stanford (Transac-
tions American Society of Civil Engineers, Vol. LVI, 1905); "The Preserva-
tion of Structural Timber," Weiss (McGraw-Hill Book Co., 1915); Bulletins
of American Railway Engineering Association; "Handbook" (1916) and
other Publications of the American Wood Preservers Association; also, other
Publications of United States Department of Agriculture; etc., etc.

335

336 ORGANIC STRUCTURAL MATERIALS

The field of wood preservation has not been occupied to the
same extent in the United States as in Europe. Woods have
been more plentiful in the United States, where, consequently,
the demands for construction have hitherto been along extensive,
instead of intensive, lines.

A study of the subject of wood preservation from a local stand-
point was inaugurated by the American Society of Civil Engi-
neers in 1880, and the report issued by this Society five years
later is yet recognized as text. The study thus commenced was
continued by the United States Department of Agriculture,
which, having organized a Division of Forestry, issued its first
bulletin in 1887. The situation in the United States today sug-
gests the situation as it was in England some years ago; save
that English engineers were obliged to learn from the beginning,
whereas Americans have profited from successes and failures of a
century of European practice.

The price of wood is advancing in the United States; and,
dependent upon this, the practice of wood preservation is rapidly
becoming more general. Prior to 1901 only fifteen timber pre-
serving plants were in operation, while, during the six successive
years, this number was increased to fifty.1 Nearly ten per cent,
of the total number of railway ties recorded as having been pur-
chased during 1905 received preservative treatment of some kind.

A French authority states that one hundred and sixty-seven
wood-preserving substances or processes were tried or introduced
prior to 1874,2 while Weiss enumerates two hundred and sixty-
eight patents granted in the United States alone in this field since
that year.3 Most processes and chemicals included in these and
other lists have, however, been abandoned. In 1885, the Com-
mittee of the American Society of Civil Engineers reported fully
upon only four preservatives and processes; and, in spite of the
time that has elapsed since this report was rendered, these four
are yet regarded as the most important.

It is hardly probable that many methods now unknown will be
successfully introduced in the future, because years must elapse
before the efficiency of a material or a method can be proved by

(United States Forest Service, Circular No. 43, p. 6). Weiss
enumerates one hundred and ten wood-preserving plants as existing in the
United States in 1914 (pp. 255-258).

2 "Traite de la conservation desbois," Paulet (Paris, 1874).

3 "Preservation of Structural Timber," Weiss (1915).

PRESERVATIVES APPLIED WITHIN WOODS 337

actual tests. Woods are more costly and chances less war-
ranted than in former years. As distinct from the development
of new practices, however, it is probable that in the future more
attention will be given to perfecting practices already known, and,
that results obtained in the United States, will ultimately be
more uniformly satisfactory than at the present time.

The subject is one that requires attention along three lines,
namely: the materials used to preserve woods, the processes used
to force such materials into the woods, and the woods that will
best receive and respond to the preservative materials thus used.

PRESERVATIVE MATERIALS

Salt, formaldehyde, lime, sulphate of iron, tannin, oils, arsenic,
and many other substances have been tried or considered for
preserving woods. Of this entire series copper sulphate, zinc
chloride, mercury bichloride, and creosote, either separately or
in combinations, have succeeded best; while of this smaller list,
zinc chloride and creosote are now most used.1

irThe following list is taken from "Handbook on Wood Preservation"
(American Wood Preservers' Association, p. 27, 1916). It enumerates some
of the substances which have been proposed as means of protecting wood
against destruction by fire, fungi, and woodborers :

Aluminum sulphate Petroleum oils

Animal oils Potassium carbonate

Barium carbonate Potassium nitrate

Barium sulphate Resins

Borax Sodium carbonate

Cedar oil Sodium chloride

Copper sulphate Sodium fluoride

Creosotes (coal-tar, Sodium muriate

water-gas-tar, wood, Sodium sulphate

petroleum) Sulphuric acid

Crude oil Tannin

Fish oil Tar

Glue Tartaric acid

Gums (various) Vegetable oils

Iron sulphate Wax

Lime hydrate Whale oil

Linseed oil Zinc chloride

Magnesium sulphate Zinc sulphate
Mercuric bichloride
Molasses and low syrups

338 ORGANIC STRUCTURAL MATERIALS

Wood preservatives may be divided as they do, or do not,
dissolve in water. First, the salts of metals dissolve in water,
and, for this reason, eventually escape if used where it is wet;
but second, creosote, which is an oily mixture, does not dissolve
in water. Creosote is much more permanent in its effects than
are the salts of metals. It should be remembered that the
influence of any chemical may continue for a short time after
the removal of the chemical.

TANNIN (CnHioOg). — Tannin is an antiseptic and coagulant.
Tannin and tannic acid are the same.1 Tannin is present in
parts of many trees and doubtless influences the natural dura-
bility of woods. It is used in the preparation of leather, as well
as in the artificial preservation of woods, although, in the latter
case, it is used only in combination with other substances.

Tannin serves in this connection, together with glue, in what
are known as the "zinc tannin processes." The leather-like
solids which result during these processes from the action of the
tannin upon the glue, fill up the pores of the wood and retard the
escape of zinc chloride, which is soluble in water.

COPPER SULPHATE (CuSO4.5H2O).— This is the blue
vitriol of commerce. Chapman experimented with wood soaked
in copper sulphate as early as 1816. Boucherie, who concerned
himself with methods for forcing preservatives into woods rather
than with the preservatives themselves, after employing various
antiseptics, finally pronounced in favor of copper sulphate; and
in consequence of this, the name of Boucherie is associated with
copper sulphate and also with the process used for introducing it
into wood. Copper sulphate is a very valuable wood antiseptic
but it dissolves readily in water and escapes easily from the wood.
It is decomposed when brought into contact with iron. Very
little of it is now used in wood preservation in the United States.

MERCURY BICHLORIDE (HgCl2).— The application of mer-
cury bichloride in wood preservation was first suggested by
John Howard Kyan in England in 1833. Mercury bichloride
is the most active of all wood preservatives in use. Very small
quantities are effective, and because the quantities needed are so
small the actual cost, although considerable, is not as great as at
first appears. It dissolves in boiling water, and once within the

1 In the strictly chemical sense, tannic acid is not a true acid, but an anhy-
dride of an acid, belonging to the class of phenols. Tannin is therefore the
more nearly correct name. The two terms refer to the same substance.

PRESERVATIVES APPLIED WITHIN WOODS 339

wood, resists the actual moisture of reasonably dry places much
longer than do copper sulphate and zinc chloride. On the other
hand, mercury bichloride attacks iron;1 in spite of the small
quantities necessary it is comparatively costly, and it is very
poisonous to human beings.2

ZINC CHLORIDE (ZnCl2). — Zinc chloride, which is obtained by
dissolving metallic zinc in hydrochloric acid, is a cheap and very
good wood preservative, its toxic effects upon wood-destroying
fungi being about equal to those of creosote ; also it has an affinity
for wood fiber into which it penetrates to a considerable depth.
Its chief fault is that it attracts water and dissolves easily in it.
Experience shows, however, that it will remain in timber in
reasonably dry locations for many years. It cannot be used in
marine constructions, but has caused railway ties which would
normally fail in four or five years to remain sound for ten or more
years. Many million pounds of zinc chloride are now used
annually in the United States in treating wood.

Zinc chloride is the cheapest wood preservative practically
available in this country, and in spite of defects that have led
most European railways to cease using it, is highly regarded as
an antiseptic that meets some temporary American conditions.
Burnett first called attention to the value of zinc chloride as a
wood preservative in 1838.

CREOSOTE.3 — The name creosote applies to products derived

1 The reaction is as follows: Fe + HgCl2 = FeCl2 + Hg.

2 The antidote, when this active poison is taken into the stomach, is fresh
milk or else egg water made by dissolving three or four raw eggs in one
quart of water.

3 REFERENCES. — "Coal-tar and Ammonia," Lunge; "Causes Underlying
the Limited Production of Creosote in the United States" (Forestry and Irri-
gation, October, 1906, pp. 482-484); "Fractional Distillation of Coal-tar
Creosote," Dean and Bateman (United States Forest Service, Circular No.
80); "Quantity and Character of Creosote in Well-preserved Timbers,"
Alleman (United States Forest Service, Circular No. 98); "The Analysis and
Grading of Creosotes" (United States Forest Service, Circular No. 112);
"Volatilization of Various Fractions of Creosote after their Injection into
Wood," Teesdale (United States Forest Service, Circular No. 188); "Modi-
fication of the Sulphonation Test for Creosote," Bateman (United States
Forest Service, Circular No. 191). Other Publications of the United States
Forest Service. Manual, 1911, and other Publications American Railway
Engineering Association. Proc. American Wood Preservers' Association.
Specifications American Telephone and Telegraph Company. "Coal-tar
Distillation," Warnes (D. Van Nostrand Company, 1914). "Preservation
of Structural Timber," Weiss (McGraw-Hill Company, 1915).

340

ORGANIC STRUCTURAL MATERIALS

from water-gas tar and wood; but, in construction, unless other-
wise noted, it now refers principally to a mixture distilled from
coal-tar. Coal-tars vary and the mixtures obtained from them
during distillation vary also. It is, therefore, particularly un-
fortunate that there can be no chemical formula for creosote.
The value of creosote as a wood preservative was suggested by
Bethell in 1838. Tar oil, heavy oil of tar, dead oil of tar, and
coal-tar creosote are different names for the same material.

Water-gas-tar and wood creosotes are antiseptics, but their
success with woods is not to be compared with that which has
followed the use of coal-tar creosote. Wood creosote has a sweet-
ish, burning taste, with an odor that resembles that of smoked

FIG. 73. — Cross-section of pole, showing penetration of creosote.

meat or fish.1 Beef cured in wood-smoke owes much of its flavor,
as well as its durability, to the influence of the volatile wood creo-
sote present in the smoke. All creosote, whether made from
wood, water-gas tar, or coal-tar, is poisonous to human beings.

Coal-tar creosote stands by itself among the wood preserva-
tives. The others dissolve in water, but creosote, in addition to
being an antiseptic, is nearly insoluble in water. Creosote pre-
vents rot, and also protects wood from the attacks of terrestrial
and marine woodborers. The salts of metals do not materially
lessen the porosity of wood, but creosote, in sufficient quantities,
fills and stiffens within the cell-structures, shuts off the air, with-

1 For references with regard to wood creosote, see " Report on Wood Creo-
sote Oil," Bixby (United States Forestry Bulletin No. 1); United States
Dispensatory; "The Preservation of Structural Timber," Weiss (p. 86).

PRESERVATIVES APPLIED WITHIN WOODS 341

out which fungi cannot live, and is the only preservative in com-
mon use that keeps wood-fibers dry.

No real difference of opinion exists with regard to the value of
creosote, the use of which depends almost entirely upon its
availability and cost. In Europe, where creosote is compara-
tively plentiful and cheap, engineers use it for ties and in almost
all wood-work that requires preservation. Americans now use it
to prevent rot in railway ties, mud sills, bridge timbers, and pav-
ing blocks, and to protect timbers designed for marine construc-
tions from teredos and limnoria. Creosote is not yet used as
widely in this country for ties as it is abroad, but its use as a tie
preservative is increasing.

As manipulated in gas works, mineral coal yields illuminating gas,
ammoniacal liquid, coal-tar, and coke. Of these, the tar, which is a
sticky black substance, is separated by distillations conducted between
certain temperatures, into (1) light oils, that is oils lighter than water,
(2) middle oils, (3) heavy oils, that is oils heavier than water, and (4)
residue or pitch. The variable mixture obtained during the third dis-
tillation is called creosote. This is also shown on the diagram.

Coal

Gas Ammoniacal Tar Coke

Liquid

Light Oils Middle Oils Heavy Oils or Pitch

Creosote

The list that follows, although incomplete, is sufficient to show the
complex nature of coal-tar.1 As a matter of fact, almost two hundred
definite chemical compounds can be separated when this material is
subjected to destructive distillation.

When coal-tar is submitted to distillation and rectification, it yields,
among others, the following products in varying proportions:1

1. Solids. Naphthalene, methyl-naphthalene, acetyl-naphthalene
diphenyl, fluorene, anthracene, phenanthrene, fluoranthene, methyl-
anthracene, retene, chrysene, pyrene, picene, and carbazol.

2. Liquids. These may be neutral hydrocarbons, acids, ethers of
acids, or their bases. The neutral hydrocarbons are benzene, toluene,
methyl- toluene, and iso-xylene, pseudocumene, mesitylene, and cymene.
The acid constituents are phenol, orthocresol, paracresol, metacresol,
phlorol, rosolic acid, pyrocatechin, and creosote, consisting of the methyl
ethers of pyrocatechin and its homologues. There are also present,

1 " Coal-tar and Ammonia," Lunge (London) United States Dispensatory;
"Coal-tar Distillation," Warnes (D. Van Nostrand Company, 1914).

342 ORGANIC STRUCTURAL MATERIALS

probably in combination with the ammonia of the ammoniacal liquor,
acetic, butyric, carbonic, hydrocyanic, sulphocyanic, and hydrosul-
phuric acids. The bases are ammonia, methylamine, ethylamine,
phenylamine, pyridine, picoline, lutidine, collidine, leucoline, iridoline,
cryptidine, acridine, coridine, rubidine, and viridine.

3. Gases, (a) Illuminating gases. Acetylene, ethylene, propylene,
butylene, allylene, crotonylene, terene, and vapors of benzene, styrolene,
naphthalene, methyl-naphthalene, fluorene, fluoranthene, hexane, hep-
tane, and octane. (6) Heating and diluting gases. Hydrogen, marsh-
gas (methane), carbon monoxide, (c) Impurities. Carbon dioxide,
ammonia, cyanogen, methyl-cyanide, sulphocyanic acid, hydrogen sul-
phide, carbon disulphide, carbon oxysulphide, and nitrogen.

A highly prized creosote is obtained as a by-product from Newcastle
coals burned in the vicinity of London. This creosote, known as
" London oil," is thick and heavy. The English Midland districts pro-
duce lighter creosotes, known as "country oils." German creosote is
much employed. Much, but not all, good creosote now used in this
country is imported, the United States not yet having met the demand
for this product. Also, much American creosote contains an excess of
naphthalene.

Chemical, physical, and physiological results are brought about by
the several ingredients that make up creosote. The wood is acted upon
by the carbolic acid, cresylic acid, and associated antiseptics. The cells
are treated by, or filled with thick, gummy oil and naphthalene, and the
creosote, as a whole, is like camphor in that it is disliked by the lower
forms of life.1

It should be noted that creosotes differ in their behavior when under
water. Thick London oils have resisted disintegration in marine posi-
tions for forty years, while some American creosotes, applied under con-
ditions that prevail in some parts of this country, have failed after having
been exposed to the action of water for a few months.2

Creosote should be thick, since thin oil is correspondingly less stable.
The specific gravity should be greater than that of water. The influ-
ence of temperature is important, because some of the ingredients, relied
upon to solidify within the wood when they have cooled, do not distil
save at high temperatures. Tidy wrote upon this subject as follows:3

1 " Descriptions of Creosote Best Suited for Creosoting Timber," Tidy
(Appendix 7); Boulton on "Antiseptic Treatment of Timber," the Institu-
tion of Civil Engineers, London; "Coal-tar and Ammonia," Lunge (Third
Edition, London, pp. 473-477).

2 "Changes which take place in Coal-tar Creosote during Exposure,"
von Schrenk, Fulks, and Kammerer (American Railway Engineering
Association, Bulletin No. 93, November, 1907).

3 "Antiseptic Treatment of Timber," Boulton (The Institution of Civil
Engineers, London, p. 51).

PRESERVATIVES APPLIED WITHIN WOODS 343

"Believing strongly as I do in the value of those constituents of the oil
that are the most difficult to volatilize, I have deemed it right to sug-
gest a clause to the effect that the creosote shall contain at least 25 per
cent, of matters that distil over at about 600 degrees Fahrenheit/'1

The ingredients or groups of ingredients in coal-tar creosotes that are
thought in the United States to exert much influence in wood preserva-
tion are light oils, naphthalene, anthracene, or anthracene oils and tar
acids. French engineers attribute much to the presence of tar acids,
while in England, credit is given to acridine. Because of the complex
nature of creosote and difficulties connected with analyses, most specifi-
cations omit mention of all but a few of the components and confine
themselves to important characteristics and reactions that indicate the
genuineness of creosote as a whole.2

Mixed Coal-tar Creosotes. — Pine resin has been used to thicken creosote
designed for the treatment of paving blocks.3 Coal-tar is often mixed
with pure creosote, the defense being that the supply of pure creosote
is insufficient. Other materials or mixtures are also used with pure
creosote. It is needless to say that when pure coal-tar creosote, free
from the mixture of other substances, is specified that creosote only
should be employed.

The fact that creosote is so variable renders the more neces-
sary some form of specification or control. It is unfortunate that
some compounds yet sold as creosote have so little to commend
them beyond the name, since failures during this more or less for-
mative period tend to retard the use of the legitimate mixture.

The properties of creosote are of vital importance. It should
not be forgotten, however, that there are other factors that exert
an equal influence upon the preservation of wood by creosote.
The method of application is one of these factors. This should
be such that deep impregnation, and the wide diffusion of the
creosote, particularly through the outer parts of the timber,
result. A poor quality of creosote well injected may yield better
results than a good quality of creosote poorly injected.

1 Report of Tidy (Boulton on "Antiseptic Treatment of Timber," the
Institution of Civil Engineers, London, p. 51).

2 About 55,000,000 gallons of creosote were used in the wood-preserving
plants of the United States during the year 1908. Of this amount, about
thirty per cent, was produced in this country, while the balance, about
seventy per cent., was imported principally from England, Germany, and
Canada.

3 See Creo-Resinate Process.

344 ORGANIC STRUCTURAL MATERIALS

Specifications for creosotes are of two kinds. First, certain
properties that the creosote should possess are specified; and
second, methods of analysis by which the existence of these prop-
erties is proved or the properties measured, are specified. It is
needless to say that these two fields depend upon one another and
that the specifications often overlap.

Specifications for Creosote. — Creosote, once purchased largely
on faith, is now bought under more or less rigidly enforced speci-
fications. Controlling items regardless of the purposes for which
the oil is to be used relate, principally, (1) to its origin, (2) to the
limits of the distillation ranges, (3) to its specific gravity, and
sometimes (4) to the percentages of several constituents.

(1) The origin of creosote is controlled by securing it from reputable
dealers. (2) The determination of the temperatures between which
certain fractions of the original bulk distil is of fundamental importance,
since slight changes cause considerable variations to take place in the
results of the analysis. (3) It is usually specified that creosotes should
have specific gravities of from 101 to 112. (4) The percentages of cer-
tain components as tar acids and naphthalene are sometimes stated.

English practice is based upon the Tidy specification,1 which is
as follows: 1. " Creosote should be completely liquid at a tem-
perature of 100 degrees Fahrenheit, no deposit afterwards taking
place until the oil registers a temperature of 93 degrees Fahren-
heit." 2. "The creosote should contain at least twenty-five
per cent, of constituents that do not distil over at a temperature
of 600 degrees Fahrenheit." 3. " The creosote shall yield a total
of eight per cent, of tar acids."2

Of the specifications employed in the United States those pre-
pared by The American Railway Engineering Association, The
American Telephone and Telegraph Company, and The United
States Forest Service, are, on the whole, most important.

1 See Boulton on "Antiseptic Treatment of Timber" (The Institution of
Civil Engineers, London, p. 51). Several characteristic European speci-
fications appear with Chanute's paper "Preservation of Railway Ties in
Europe" (Trans. American Society of Civil Engineers, Vol. XIV).

2 Some American and foreign specifications are shown in comparison with
one another in a paper entitled, "Changes which take place in Coal-tar Creo-
sote during Exposure," von Schrenk, Fulks and Kammerer (American
Railway Engineering Association, Bulletin No. 93, November, 1907).

PRESERVATIVES APPLIED WITHIN WOODS 345

The specification prepared by The American Railway Engi-
neering Association is as follows:

Standard Grade of Creosote Oil (Also Known as No. 1 Oil). — The oil
used shall be the best obtainable grade of coal-tar creosote; that is, it
shall be a pure product obtained from coal-gas tar, or coke-oven tar,
and shall be free from any tar, oil or residue obtained from petroleum
or any other source, including coal-gas tar or coke-oven tar; it shall be
completely liquid at thirty-eight (38) degrees Centigrade and shall be
free from suspended matter; the specific gravity of the oil at thirty-eight
(38) degrees Centigrade shall be at least 1.03. When distilled by the
common method — that is, using an eight (8) ounce retort, asbestos-
covered, with standard thermometer, bulb one-half (^) inch above the
surface of the oil — the creosote, calculated on the basis of the dry oil,
shall give no distillate below two hundred (200) degrees Centigrade, not
more than five (5) per cent, below two hundred and ten (210) degrees
Centigrade, not more than twenty-five (25) per cent, below two hundred
and thirty-five (235) degrees Centigrade; and the residue above three
hundred and fifty-five (355) degrees Centigrade, if it exceeds five (5)
per cent, in quantity, shall be soft. The oil shall not contain more than
three (3) per cent, water.

In addition to the above standard specification, the two following
grades can be used in cases where the higher-grade oil cannot be pro-
cured. It should be understood that where it is necessary to purchase
grades No. 2 and No. 3 consideration should be given to the use of a
greater quantity of creosote oil per cubic foot.

Specification for No. 2 Grade Creosote Oil. — The oil used shall be the
best obtainable grade of coal-tar creosote; that is, it shall be a pure
product obtained from coal-gas tar, or coke-oven tar, and shall be free
from any tar, oil or residue obtained from petroleum or any other source,
including coal-gas tar or coke-oven tar; it shall be completely liquid at
thirty-eight (38) degrees Centigrade and shall be free from suspended
matter; the specific gravity of the oil at thirty-eight (38) degrees Centi-
grade shall be at least 1.03. When distilled by the common method —
that is, using an eight (8) ounce retort, asbestos-covered, with standard
thermometer, bulb one-half (^) inch above the surface of the oil — the
creosote, calculated on the basis of the dry oil, shall give not more than
eight (8) per cent, distillate below two hundred and ten (210) degrees
Centigrade, not more than thirty-five (35) per cent, below two hundred
and thirty-five (235) degrees Centigrade; and the residue above three
hundred and fifty-five (355) degrees Centigrade, if it exceeds five (5)
per cent, in quantity, shall be soft. The oil shall not contain more
than three per cent, water.

346 ORGANIC STRUCTURAL MATERIALS

Specification for No. 3 Grade Creosote Oil. — The oil shall be the best
obtainable grade of coal-tar creosote; that is, it shall be a pure product
obtained from coal-gas tar or coke-oven tar and shall be free from any
tar, oil or residue obtained from petroleum or any other source, including
coal-gas tar or coke-oven tar; it shall be completely liquid at thirty-
eight (38) degrees Centigrade and shall be free from suspended matter;
the specific gravity of the oil at thirty-eight (38) degrees Centigrade
shall be at least 1.025. When distilled by the common method — that is,
using an eight (8) ounce retort, asbestos-covered, with standard ther-
mometer, bulb one-half (^) inch above the surface of the oil — the creosote,
calculated on the basis of the dry oil, shall give not more than ten (10)
per cent, distillate below two hundred and ten (210) degrees Centigrade,
not more than forty (40) per cent, below two hundred and thirty-five
(235) degrees Centigrade; and the residue above three hundred and fifty-
five (355) degrees Centigrade, if it exceeds five (5) per cent, in quantity,
shall be soft. The oil shall not contain more than three (3) per cent, water.

The specification of the American Telephone and Telegraph Company1
is as follows :

General. — The material desired under these specifications is that
known as dead oil of coal-tar, or coal-tar creosote, obtained through the
distillation of gas tar produced by the destructive distillation of bitu-
minous coal, either in the manufacture of coal gas, or in the manufacture
of coke by the by-product process. It shall be without adulteration.
Information shall be furnished on request as to the origin of the oil and
the names of the parties through whose hands it may have passed. A
copy of any analysis of the oil that may have been made prior to its use
shall also be furnished. The right is reserved to take representative
samples of the oil and test the same wherever desired.

Requirements. — All dead oil of coal-tar furnished under these speci-
fications shall conform to the following requirements :

First. — The oil shall have a specific gravity of at least one and three
one-hundredths (1.03) at thirty-eight degrees Centigrade (38°C.).

Second. — The oil shall be thoroughly liquid at a temperature of thirty-
eight degrees Centigrade (38°C.).

Third. — When one hundred grams of the oil are distilled in accordance
with the requirements of the specifications for the analysis of dead oil
of coal-tar or coal-tar creosote hereinafter referred to —

(a) Not more than five (5) per cent, shall distil off up to 205°C.

(b) Not more than thirty-five (35) per cent, shall distil off up to 235°C.

(c) The fraction coming over between 210°C. and 235°C. shall solidify
on cooling to 20°C.

(d) -Not more than eighty (80) per cent, shall distil off up to 315°C.

1 Specification No. 3,340, dated March 11, 1911 (in force April, 1912).

PRESERVATIVES APPLIED WITHIN WOODS

347

(e) The oil shall not contain more than1 two (2) per cent, of water.

(/) The quantity of tar acids present in the fractions distilling below
300°C. shall not exceed eight (8) per cent, (measured by volume) of the
total sample distilled.

(gr) The sulphonation residue from the fraction distilling between
300°C. and 360°C. shall not exceed twenty-five one hundredths (0.25)
cubic centimeters.

Fourth. — The oil shall be free from acetic acid and acetates.

Fifth. — The constituents of the oil insoluble in benzol shall not exceed
one (1.0) per cent, by weight.

Thermometer

Sheet Asbestos should
rest against Glass Neck
must never Touch Cork
Stopper

Retort

Asbestos
Sheet

Wire Gauze

Bunseu Burner

FIG. 74. — Apparatus for analysis of creosote used by American Telephone

and Telegraph Co.

Analysis. — The oil shall be analyzed in accordance with the methods
outlined in the Specifications for the Analysis of Dead Oil of Coal-tar
or Coal-tar Creosote.

1 NOTE. — When unseasoned timber is being treated for the Telephone
Company by the cylinder pressure process, using steam for seasoning, the
oil may contain not more than five (5) per cent, of water. But in case
more than two (2) per cent, of water is present in the oil, the quantity of
the preservative added to the timber shall be increased by an amount
sufficient to ensure that the required amount of oil computed on a water-
free basis has been taken up by the timber.

348 ORGANIC STRUCTURAL MATERIALS

The United States Forest Service Specification for Creosote
gives much attention to methods of analysis.1

Specifications for Analysis of Creosote. — The importance of
details in analyzing creosotes has been mentioned. The methods
and devices employed in determining the proportions of creosote
separated between certain temperatures, the methods of measur-
ing viscosity, and those employed to determine other properties,
influence the results obtained. This is partly shown in the quo-
tation that follows:2

"The most important part of a creosote analysis is the fractional
distillation, since by this operation an approximate determination is
made of the relative proportions of the most important substances in
tar oil. There has been considerable divergence of opinion as to the
best way of carrying out the fractionation of tar oils, some recommend-
ing a retort as a distilling vessel and certain temperatures for taking
fractions, others recommending a distilling flask and a different set of
temperatures."

The shape of the distilling vessel is important, since it exerts
an influence upon the quantities and the constituents of the
parts, or fractions that are distilled. It is also necessary to
decide upon the limits of temperature and the number of these
limits that are to isolate, or divide the parts or fractions.

The forms that follow show methods of reporting analyses.
The first and second forms have been used to report the results of
analyses in which the oil was divided into ten and eleven frac-
tions, while the last form was used to report an oil that ran high
in naphthalene.

l" Standard Method for Analysis of Coal-tar Creosote," von Schrenk,
Fulks, and Kammerer (American Railway Engineering Association, Bulletin
No. 65). See also American Railway Engineering Association Manual,
1911, p. 441. "The Fractional Distillation of Coal-tar Creosote," Dean and
Bateman (United States Forest Service, Circular No. 80).

2 United States Forest Service, Trade Bulletin No. 13; other references are
United States Forest Service Circular No. 80; American Railway Engineer-
ing Association Bulletins No. 65 and No. 72; Specifications of the American
Telephone and Telegraph Company, New York Telephone Company; also
sources enumerated in preceding footnote.

PRESERVATIVES APPLIED WITHIN WOODS
ANALYSIS OF DEAD OIL OF COAL TAR

349

Sample No. 1
Manufactured by :
Purchased from :

Date:

191 .

SUMMARY OF RESULTS

Specific Gravity at 38°C. :
Condition at 38°C. :

FRACTIONATION

Weight of retort

Weight of retort and oil

Fraction
number

Temperature

Per cent.

Weight of
vessel

Weight of
vessel and
contents

Weight
of
contents

!

1

170°C.

2

170°C. to 205°C.

3

205°C. to 210°C .

4

210°C. to 235°C.

5

235°C. to 245°C.

6

245°C. to 270°C.

7

270°C. to 300°C.

8

300°C. to 315°C.

9

315°C. to 360°C.

10

Residue (in retort)

Total per cents, found:

Loss per cent. :

Oil distilling below 205°C. :

Oil distilling below 235°C. :

Oil not distilling below 315°C:

Water:

Sulphonation residue:

Tar acids :

Insoluble in benzol :

Acetic acid or acetates :

Condition of naphthalene fraction (210°-235°) when cooled to 20°C.

Per cent.

Per cent.

Per cent.

Per cent.

Cubic centimeters

Cubic centimeters

Per cent.

350
No. 2

ORGANIC STRUCTURAL MATERIALS

Creosote

. — DISTILLATION No. 23

50 Date 3/ I/ 17

Analyst

No.

Temp.

Flask

Flask

Dist.

Per cent.

Character

1

170

49.53

47.34

2.19

0.876

1. Water — some naph.

2

170-205

47.11

45.49

1.62

0.648

2. Light oil — some naph.

3

205-210

42.80

40.77

2.03

0.812

3. Light oil — some naph.

4

210-235

86.45

51.97

34.48

13.792

4. Nearly solid.

5

235-245

71.44

46.34

25.10

10.040

5. Solid.

6

245-255

68.80

49.18

19.62

7.848

6. Semi-solid.

7

255-270

70.90

48.78

22.12

8.848

7. Very thin paste.

8

270-285

60.40

44.73

15.67

6.268

8. Very thin paste.

9

285-300

59.59

41.02

18.57

7.428

9. Thin paste.

10

300-320

80.82

52.38

28.44

11.370

10. Thick paste.

11

320-350

98.32

50.37

47.95

17.180

11. Solid.

Res

idue

128.55

97.32

31.23

12.492

Remarks: Oil almost liquid

99.608

No. 3. REPORT OF TEST OF COAL-TAB CREOSOTE

Date: July 10, 1917. Analyst

Sample from overflow pipe. Temperature, 48°C.

Oil supplied by— Boiling, 210°C.

Specific gravity, 1 . 021. Melting point, 46°C.

Weight Retort 104.71 gr.

Retort and Contents, 204.47 gr. Contents, 99.76 gr.
Retort and Residue, 120 . 73 Residue, 16 . 02 gr.

DISTILLATION

Temp.

Fraction

Tube

Weight of
tube and
contents

Con-
tents

Per cent,
ol
whole

-170°
170°-205°
205°-210°
210°-235°
235°-240°
240°-270°
270°-316°

Phenols,hydrocarbonsand water
Phenols and cresols

22.44
18.89
20.25
20.90
12.91
19.85
17.44

22.33
22.39
27.43
67.75
18.50
31.01
26.37

0.09
3.50
7.18
46.85
5.59
11.16
8.93

0.09
3.50

7.20
46.94
5.60
11.19
8.95
16.06
0.47

Phenols and naphthalene ....

Naphthalene . ...

Naphthalene and anthracene oil
Anthracene oil

Anthracene

Residue

Loss

Total

100.00

Time : ( 40° to 210° 29 min. 235° to 270° 27 min.

\ 210° to 235° 21 min. 270° to 316° 29 min.

•Percentage of naphthalene 53.34 per cent, (obtained by adding half of the
percentage of the phenols and naphthalene, and naphthalene and anthracene
oil fractions to the percentage of the naphthalene fraction).

PRESERVATIVES APPLIED WITHIN WOODS 351

Required Quantities of Creosote. — These depend upon the
way in which the wood is used. For example, large quantities
of creosote cannot be used in paving blocks because of the possi-
bility that such blocks will annoy pedestrians by "bleeding" or
giving up creosote when exposed to the sun. On the other hand,
timbers that are to be submerged in marine positions require
considerable quantities of creosote.

Practices differ with localities, woods, and the uses for which
the woods are intended. In the United States, railway ties are
sometimes treated with quantities as small as six or eight pounds
to the cubic foot, although the usual local practice is to treat
them with ten or more pounds to the cubic foot. Depending
upon a wide range of conditions, piles are usually made to receive
from twelve to twenty-four pounds to the cubic foot.

An eastern wood preserver advises as follows :

"In this section of the country (New York) it is customary to subject
a railroad tie to a treatment of eight to twelve pounds of creosote per
cubic foot of wood. If we figure that a standard tie of seven inches by
nine inches by eight feet six inches is being used, this would make a total
injection of thirty to forty-four pounds of creosote oil into each tie,
depending upon the treatment used. The treatment, of course, depends
upon the conditions under which the tie is to be used, whether the con-
ditions are severe or mild."

"In northern waters, twelve to sixteen pounds of creosote oil per cubic
foot of wood is considered sufficient for the protection of the piling.
However, in the south, where the piling is subject to the ravages of the
teredo, etc., it is considered good practice to creosote the piling to point
of refusal, which is from twenty to twenty-four pounds per cubic foot."

It should be remembered that some engineers believe that much
of the value of creosote depends upon the fact that it keeps wood-
fiber dry, and, therefore, think that it should be used in compara-
tively large quantities, as in the so-called " full-cell" processes;-
while others regard its antiseptic value more exclusively, and,
in ties, use smaller quantities, as in the " empty-cell" processes.

Distribution of Creosote. — Experience has shown that the
distribution of creosote throughout every part of every piece is
impracticable and unnecessary, but that the thorough penetra-
tion into the sapwood and outer parts is of vital importance. It
is fortunate that sapwood, because of its comparative porosity,
and because of its position upon the outside of the timber, receives
creosote so much more easily than heartwood receives it.

352 ORGANIC STRUCTURAL MATERIALS

The tendency of preservatives to lodge near surfaces indicates
the desirability of framing timbers before they are treated.
Europeans bore ties before they are treated, and finally insert-
wooden dowels into the borings; these dowels, and not the ties,
receive the spikes.

MISCELLANEOUS MATERIALS.— Several proprietary wood-
preserving compounds are in existence; these, although recom-
mended for ties, are principally used for small pieces, or for fresh
exposures where timbers are cut and framed upon the ground.
Carbolineum, woodiline, spiritine, and others are of this group.

Carbolineum. — The base of this mixture is understood to be
a modified coal-tar creosote that differs from ordinary creosote in
that the lower distilling fractions have been largely removed.
Several compounds are sold under the name " Carbolineum."1

Avenarius Carbolineum. — This mixture, invented by Avenar-
ius in Germany, in 1869, has been upon the market since 1876.
An analysis furnished by the manufacturer, published by Filsinger
in the "Chemicker Zeitung" of April 18, 1891, and referred to in
Lunge's " Coal-tar and Ammonia," is as follows:

ANALYSIS

Color Red brown.

Specific Gravity at 62 degrees F 1 . 128

Viscosity at 62 degrees F. (water 1) 10.00.

Mineral matter 0. 03 per cent.

Flashing point 270 degrees F.

Burning point 370 degrees F.

Begins to distil at 445 degrees F.

Distils from 445 degrees to 520 degrees F 10. 6 Vol. per cent.

Distils from 520 degrees to 570 degrees F 12.0 Vol. per cent.

Naphthalene (at 410 degrees to 446 degrees F.) No separation.

Phenols (carbolic acid aac. Seubert) 0.00 per cent.

Residue a clear red-brown thick fluid.

Avenarius Carbolineum is described by the manufacturers as
follows :2

"To give a short definition for Avenarius Carbolineum, we would
say that it is a liquid oil from the very highest boiling and least volatile
fractions distilled from coal-tar. It is of course a mixture of oils and

1 The name "Carbolineum" was registered by Richard Avenarius at the
Patent Office in Washington, see No. 14,048. The American Telephone &
Telegraph Company purchase "Carbolineum" under the specifications
included in the Appendix.

2 Correspondence, February 24, 1912, quoted by permission.

PRESERVATIVES APPLIED WITHIN WOODS 353

not a single substance, but this mixture is rigidly controlled and the
composition of this product held is more constant than any other oily
wood preservative, insuring uniformity of composition and certainty of
action."

PROCESSES USED TO INTRODUCE PRESERVATIVES WITHIN

WOODS

The process is quite as important as the material. The im-
pregnation must be deep and well distributed through the outer
parts of the pieces, and the wood must not be injured by the proc-
esses used to secure this impregnation and distribution. Within
limits, the same process may be used to introduce any preserva-
tive through any species of wood, but, in practice, certain proc-
esses have become more or less associated with certain preserva-
tives. The process may be considered as it includes (1) the
preparation, and (2) the impregnation of the wood.

Europeans once prepared practically all woods that were to
receive preservatives by first steaming them. But, at the pres-
ent time, much of the best European practice excludes the
application of steam save to woods that are to receive watery
solutions. The woods that are to receive creosotes are usually
prepared by drying. In the United States, early practices
included preparatory steaming, and it is yet thought to be better
to steam the imperfectly seasoned woods that are presented in
such quantities for treatment in the United States, than to hold
them in the yard until they are dry.

The second part of the preservative process, that is, the part
during which woods prepared by drying or by steaming are
brought into contact with the preservative, may be carried out in
many ways : woods may be dipped into or soaked in the preserva-
tive, or the preservative may be applied with a brush, or may be
forced into the wood by pressure applied within a cylinder.

Regardless of details, all methods employed to introduce chem-
ical compounds within woods may be grouped as they are (1)
Superficial Processes, (2) Non-pressure Processes, and (3) Pres-
sure Processes.

SUPERFICIAL PROCESSES

Many attempts have been made to introduce preservatives into
woods without the assistance of pressure, and several of these
attempts have yielded more or less final and satisfactory results.

354

ORGANIC STRUCTURAL MATERIALS

DIPPING, SOAKING, BRUSH APPLICATIONS.— These

methods are often applied to small pieces such as shingles and
fence posts, and sometimes to larger pieces such as telegraph
poles; but, in the latter case, they are normally considered where
treatment is to be confined to<certain parts of the timber. As for
example, in the case of telegraph poles it is usually best to treat
only those portions that are to extend into the ground.

Dipping and soaking include longer or shorter immersions in
the preservative. Both practices are economical as to labor, while

FIG. 75. — Treating poles by brush method.1

the latter has the advantage of giving the preservative a better
opportunity to penetrate cracks and other places that cannot ordi-
narily be reached by brushes. When soaking is practised, the wood
should remain in the preservative for at least fifteen or twenty
minutes. Dipping should be repeated several times. The results
from both processes are better when the preservative is heated.

1 Acknowledgment to United States Department of Agriculture.

REFERENCES. — "Prolonging the Life of Telephone Poles," Grinnell
(United States Department of Agriculture, Year Book, 1905); "Brush and
Tank Pole Treatments," Crawford (United States Forest Service, Circular
No. 104); "Wood Preservation in the United States," Sherfesee (United
States Forest Service, Bulletin No. 78); "Preservative Treatment of Poles,"
Kempfer (United States Forest Service, Bulletin No. 84); etc., etc.

PLATE XVI. TROUGH EMPLOYED IN KYAN PROCESS

PRESERVATIVES APPLIED WITHIN WOODS 355

Brush applications cost more for labor than do dipping and
soaking, but the large receptacles necessary for dipping and soak-
ing are not required when preservatives are applied with brushes.
In the latter case the warm preservative is brushed on much as
paint is applied. The wood should receive at least two coats.
The penetration is superficial, but the fact that the piece is sur-
rounded by what is really a thin, antiseptic " case" is of assistance
as long as the case can be preserved.

NON-PRESSURE PROCESSES

THE KYAN PROCESS.— This was probably the first wood-
preserving process used in the United States, and it is yet among
the best. But its usefulness is limited, because the preservative
employed is so expensive.

The timbers are placed in open non-metallic troughs filled
with mercury bichloride solution and are held below the surface
of the solution by heavy weights such as large stones. The sub-
mergence thus obtained is continued for periods that depend
upon the shapes and sizes of the timbers treated. Besides the
trough, there are facilities for mixing and storing the solutions,
but the entire plant is simple and very cheap. It is compara-
tively easy to obtain good results from the Kyan process in almost
any locality. An ordinary oil cask is enough to hold several
fence posts with sufficient solution to influence the portions with
which the solution comes into contact.

It will be remembered that mercury bichloride dissolves in very
hot water, and that the strength of the solution, which diminishes
as wood is soaked in it, must be brought back to the required limit
whenever necessary. It will also be remembered that mercury
bichloride is poisonous to human beings,2 and that it attacks iron.
The Kyan method, which requires less expert care than any other,
was suggested in 1832 by an Englishman named Kyan.

THE OPEN-TANK PROCESS.— Many attempts have been
made to perfect this process which is designed to treat susceptible
timbers without the aid of cylinders. The apparatus required is
comparatively simple and the results obtained are more or less

Prolonging the Life of Telephone Poles," Grinnell (Yearbook
of Department of Agriculture, 1905).

2 If this poison is taken into the stomach the patient should receive
quantities of fresh milk, or egg water, made by dissolving three or four eggs
in one quart of water.

356

ORGANIC STRUCTURAL MATERIALS

satisfactory. The open-tank process is particularly convenient
when small quantities of impressionable woods are to be treated,
or where the treatment is to be localized as at the ends of posts or

poles. It has not yet been widely
adopted, however, nor is it likely
that it will ever be extensively em-
ployed by those who treat the
largest quantities of woods.

The timbers placed in an open
reservoir are treated with hot, and
then with cool baths of the anti-
septic solution. The changes of
temperature may be obtained as
follows : first, after the pieces have
remained in the hot preservative
for a sufficient time the fire may
be withdrawn and the preservative
allowed to cool; or second, the
pieces to be treated may be trans-
ferred from a tank containing hot
preservative to another tank con-
taining cool preservative; or again
after the pieces have remained for
a sufficient time in the hot pre-
servative the latter is replaced by
the cooler liquid.

The time required for penetration
varies with seasoning, species, and
other factors , and in every instance,
must be determined by actual test.
It should be noted that sufficient

penetration cannot be obtained from
FIG. 76.— Open-tank for Butt -

treatment of long poles. From REFERENCES. — "Prolonging the Life
''Preservative Treatment of of Telephone Poles," Grinnell (United
Poles. Kempfer (United States -. _f c A . ,, v

Forest Service, Bulletin No. 84). States Department of Agriculture, Year

Book, 1905); "The Open-tank Method

for the Treatment of Timber," Crawford (United States Forest Service,
Circular No. 101, 1907); "Brush and Tank-pole Treatments," Crawford
(United States Forest Service, Circular No. 104, 1907); "Wood Preserva-
tion in the United States," Sherfesee (United States Forest Service,
Bulletin No. 78, 1909); "Preservative Treatment of Poles," Kempfer
(United States Forest Service, Bulletin No. 84, 1911); "Preservation
of Structural Timber," Weiss (1915); etc., etc.

PRESERVATIVES APPLIED WITHIN WOODS

357

a hot solution only. On the contrary, the absorption usually takes
place during that part of the process where the oil is cool. The prin-
cipal function of the hot bath seems to be to prepare the wood for treat-
ment. A general case would be as follows: The preservative solution
is heated to from 190 degrees to 210 degrees Fahrenheit. Timbers are
then placed in the warm solution in which they are permitted to re-
main for from two to six hours, after which they are placed in the cool
solution in which they remain for from two to twelve hours.

The tanks employed in experiments upon large poles have been of
two kinds. In some, the bottoms are inclined so that poles can be
placed in and withdrawn from the tanks without the aid of derricks or
other machinery. This form is convenient, but does not represent an
economical design for permanent installation, because the large surface
of oil favors the evaporation of the preservative, and because only a
few poles can be treated at the same time.

FIG. 77. — Simple apparatus for treating posts.1

Other designs provide cylindrical or rectangular treating tanks, in
which the poles are placed vertically. Such tanks restrict the surface
of the preservative exposed to the air and are thus more economical; but,
these vertical tanks require derricks for handling the poles, and are usu-
ally intended to be operated in connection with the steam boilers em-

1 From "Preservative Treatment of Farm Timbers," Willis (United States
Department of Agriculture, Farmers' Bulletin No. 387).

358

ORGANIC STRUCTURAL MATERIALS

ployed to heat the preservative. A storage tank, an oil pump, and an
emptying tank can be added to the equipment if the amount of work
contemplated and the time required for treating each charge are of suffi-
cient importance to warrant their use.

The simplest kind of apparatus is sufficient where only a few short
pieces of responsive wood are to be treated. That shown in the lower
picture (see Fig. 77) is not likely to be satisfactory if used many
times, because the connections between the pipes and wooden barrels
cannot be prevented from leaking ultimately. A much better arrange-
ment includes a light iron tank, about the size of an oil barrel, fitted
with a U-connection of two-inch pipe, which projects out for a sufficient
distance from the side of the tank, and to which the heat is applied.
The first cost of this device is greater than the cost of that shown in
the second picture but it is more economical if permanency is desired.

It will be remembered that woods differ in receptivity, and
that some kinds receive solutions much better than others.
This is shown in some results reported by Kempfer, as follows:1

3

Details of

treatmen

t

Average

Averag

Species

No.
poles

Hot oil
hours

Cool oil
hours

Cold oil
hours

Temp, hot
oil
degrees F.

penetra-
tion
inches

absorp-
tion
pounds

Chestnut

16

10

14

228

0.30

20.7

Chestnut

8

8

14

223

0.29

21.3

Chestnut
Chestnut

24
24

6
4

14
14

225

225

0.34
0 33

23.6
20 9

Chestnut...

24

6

2

229

0 34

21 3

Chestnut....
Western Yellow (

16
42

4
3

14

2

231
170-200

0.38
3.10

20.6

81.4

Pine \

56

3

14

170-200

3.30

55.5

A specification prepared by The American Telephone and
Telegraph Company to guide the treatment of the butts of poles
by the Open-tank Method is as follows:2

"Method of Treatment.

"Length of Treated Sections. — The poles shall be arranged in the tank
so that all poles shall be covered, throughout the treating process, with
oil for a distance from the butt end of not less than that given in the
following table:

1 Condensed from United States Forest Service, Bulletin No. 84, Tables
Nos. 8 and 18.

2 Specification 2,977, March 7, 1907 (in force April, 1912).

PLATE XVII. OPEN-TANK PROCESS APPLIED TO BUTT
TREATMENT OF POLES

(a) Tank with Horizontal Bottom — The Poles Stand Vertically — The
Process is Without Change of Oil.

Injector

Condensing
Blow-off Well

(6) Tank with Horizontal Bottom— The Poles Stand Vertically— The
Process is With Change of Oil.

Acknowledgments to American Telephone and Telegraph Company.

(Facing page 358.)

PRESERVATIVES APPLIED WITHIN WOODS

359

Feet

Feet

Feet

Feet

Feet

Feet

Length of pole

25

30

35

40

45

50

Length of treated section from
butt of pole

6.0

6.5

7.0

7.0

7.5

8.0

"Hot-oil Treatment. — The poles shall be kept in the bath of dead oil
of coal-tar maintained at a temperature of not less than 212°F. for cedar,
chestnut, and partially seasoned and green loblolly pine poles, or not
less than 200°F. for seasoned loblolly pine poles, and not more than
230°F. for seasoned poles, for at least five hours, partially seasoned poles,
for at least eight hours, and for green poles, for at least ten hours.

"Cool-oil Treatment. — At the completion of the hot-oil treatment, a
sufficient quantity of cool oil shall be admitted to the treating tank to
lower the temperature of the oil to at least 100°F. The level of the oil
in the tank shall be maintained by means of an overflow outlet or an
emptying pipe controlled by a valve. Poles shall be kept in the cool
oil for at least eight hours.

"If it is not possible to lower the temperature of the oil as above
described, the oil shall be allowed to cool by atmospheric exposure. In
this case the poles shall be kept in the cooling oil until the temperature
of the oil has dropped to at least 110°F., but in no case for less than ten
hours.

"The treated section of the pole shall not be exposed to the air during
any portion of the treating process.

"Depth of Impregnation. — All poles shall be treated so that the oil
impregnation shall extend through the sapwood. One pole in ten shall
be bored to ascertain the depth of penetration and such borings shall
be made four (4) feet from the butt end. The bore hole shall be filled
with hot dead oil of coal-tar immediately after the depth of penetration
has been ascertained."

The advantages and limitations of the open-tank process have
been summarized by Kempfer as follows:1

"The tests made by the Forest Service indicate that the sapwood of a
great variety .of species, including nearly all of our common native woods,
when seasoned can be successfully impregnated by the open-tank pro-
cess. The heartwood of many species offers considerable resistance to
impregnation and cannot be so well treated without pressure. However,
with the exception of a few species having an unusually narrow sapwood,
it is believed that the thorough treatment of the sapwood portion of
round timber will afford good protection to the entire stick. Since poles

1 United States Forest Service, Bulletin No. 84, p. 17.

360 ORGANIC STRUCTURAL MATERIALS

are almost always used in the round, the open-tank process is especially
well adapted to the treatment of this class of timber. The apparatus
required is comparatively simple and inexpensive, especially where but
few poles are to be handled, and if desired can be made portable.

The open-tank process is not adapted to the treatment of woods
which are difficult to impregnate, nor to unseasoned or partially seasoned
wood, and as regards economy of operation, has not justified itself in
plants designed for the treatment of the entire pole. The large amount
of oil lost by volatilization from open tanks and the difficulty of accur-
ately gauging and regulating the amount absorbed are other disadvan-
tages."

PRESSURE PROCESSES

Pressure processes are usually employed when large quantities
of wood are to be treated. Not only are such processes conven-
ient and economical when practised upon a large scale, but the
results obtained from them are commonly more complete and
satisfactory. In practically all cases pressure is applied through
the instrumentality of cylinders. An exception, the Boucherie
process, which being of historic interest is noted for completeness,
required pressure but did not make use of cylinders.

Use of Cylinders. — The use of cylinders is not confined
to any single process or preservative. The Bethell, Burnett,
Rutgers, Wellhouse, and other pressure processes all employ
these devices. The cylinders, which are built of steel, are from
five to ten feet in diameter, and from one hundred to as much as
one hundred and eighty or more feet in length, while the thickness
of the metal is such that working pressures of from one hundred
and forty to two hundred and twenty-five pounds can be used
with safety. Special doors, pumps, reservoirs, thermometers,
gauges, and other parts complete the equipment.

Timbers to be treated in cylinders are arranged loosely on
special cars so that solutions with which they will later come into
contact may have the freest possible access to their surfaces.
The charges are then weighed or measured, and are rolled into
the cylinders, the doors of which are closed and bolted.

The manipulations that follow vary with process, preservative,
peculiarities of wood, and the wishes of those in charge. In some
cases hot air, vacuum, and solutions follow one another, while
in others the order is steam, vacuum, and solutions.

The degree of impregnation is determined by gauges that
connect with and show the level of the solutions in the cylinders.

PRESERVATIVES APPLIED WITHIN WOODS 361

A measured quantity of zinc chloride solution of known strength,
if that salt is used, or of creosote, or other preservative, is passed
into the cylinder and held there under pressure until the gauges
show that the desired amount of preservative has been absorbed.
The amount of absorption is also occasionally determined by
weighing the wood before and after treatment.

It is necessary to consider the conditions of pressure, heat, and
vacuum that exist during a process.

FIG. 78. — Pressed-steel car for cylinder-treatment of ties.1

Pressure. — Pressure produced by pressure pumps is used either before
the preservative has been forced into the wood, or, later, as a means of
forcing it into the wood. When pressure precedes saturation it is with
the idea that the compressed air stored within the wood will act subse-
quently by driving out most of the free preservative. This detail is
practised in the Rtieping and other so-called " empty-cell" processes.
In the " full-cell" processes the pressure is applied with the preservative.
It will be remembered that dry heat and steam may both be diffused
by air pressure, which may be manipulated so as to assist in several
ways. Pressures beyond one hundred and seventy-five pounds to the
square inch are seldom required. The distinction between full-cell and
empty-cell processes should be noted.

Heat. — Several results may be accomplished by manipulating heat in
and out of cylinders. The heat may be wet or dry. Moist heat, that
is, steam, expels moisture and impurities and cures green woods. Much
American practice depends upon the assumption that woody cells receive
foreign substances better when they become wet and distended by steam-

1 Photograph supplied by Allis-Chalmers Manufacturing Company, Inc.

362 ORGANIC STRUCTURAL MATERIALS

ing, although, as a matter of fact, experiments have shown that a larger
degree of penetrability is secured when the wood is very dry. Long
steaming is usually unnecessary and is often injurious. High heat,
whether wet or. dry, should be avoided. Dry heat, as applied in kilns,
cures woods as well as shrinks them. When it is applied in cylinders
to woods that are to receive preservative treatment, it acts by expelling
moisture and by warming the woods so that they will receive the pre-
servative better. Dry heat in excess of 212 degrees F. expels some of
the volatile products of the wood, which then becomes correspondingly
weak and brittle. The equivalent of this in moist heat is not known.
When heat is carried to the point where charcoal is formed the durability
of the wood is increased to some extent because the parts that are
charred are sterilized. It is needless to say that charring is not practised
with woods that are to receive antiseptics.

Vacuum. — When vacuum succeeds steam, it acts by withdrawing from
within the cell-structures of the wood vapors that have been formed
there by the steam. There is also a surprising quantity of half coag-
ulated impurity that bears witness to the necessity of some such cleans-
ing process. The results of vacuum applied to recently steamed green
wood have been described by Andrews as follows:1 "There is at this
time no appreciable amount of moisture within the cylinder. The vac-
uum pump has worked a very few minutes, however, when the vapors,
partly condensed in the pump, begin to pour from the nose of the pump,
and they continue to come for hours, filling, if the wood is green, many
barrels with sap."

The so-called "full-cell" and "empty-cell" processes should be dis-
tinguished from one another. A full-cell creosote process is based
upon the assumption that, besides acting as an antiseptic, creo-
sote coats or fills the woody cells and keeps them dry; a relatively
large amount of oil is here required. An empty-cell creosote proc-
ess is based upon the assumption that the creosote acts princi-
pally as an antiseptic, and that more or less prolonged contact
with it is sufficient; in this case much of the creosote forced into
the wood is withdrawn and saved so that this process is less
expensive.

These terms are also used where other preservatives, besides
creosote, are employed. General definitions would b6 as follows :

A full-cell process is one which fills the walls and the cavities
of the wood cells with the preservative. A maximum quantity
of the preservative is received in, and is retained by, the wood.

Hayford Process and Apparatus for Preserving Timber," E. R.
Andrews (Journal of the Franklin Institute, February and March, 1878).

PLATE XVIII. STEEL CYLINDERS DESIGNED FOR TREATING

WOOD

(Photographs by Vulcan Iron Works.)

(Facing page 362.)

PRESERVATIVES APPLIED WITHIN WOODS 363

An empty-cell process is one by which the walls of the cells
of the wood are treated with preservative. The cell cavities
are not left filled. The preservative is forced into the wood,
but much of it is then withdrawn. The amount retained is
much less than in the case of the full-cell process.

THE FULL-CELL PROCESSES. The Bethell Process.— The
Bethell Process of impregnation has always been associated
with the use of creosote. The original patent taken out in
England in 1838 did not include the word " creosote," but, in-
stead, referred to a method by which any one of eighteen sub-
stances or mixtures might be introduced into wood. Creosote
was an ingredient in one of the mixtures mentioned, and is yet
the preservative associated with this process. A distinct feature
of the Bethell Process as first practised in Europe was that the
woods to be treated were not steamed, and this detail is yet prac-
tised where the process is exactly followed.

More or less completely seasoned woods are placed in cylinders,
a vacuum is drawn by air pumps after which warm creosote is
directed into the cylinder and held under a pressure of from one
hundred to one hundred and eighty pounds until the required
absorption has taken place. It is amusing to note than an early
objection to this process was founded upon the fact that it forced
"too much creosote" into the wood.

The Bethell Process was not at first accepted in the United
States because it was costly, and because it was not designed to
treat unseasoned woods. Andrews, writing in 1878, stated that
this "defect" of the Bethell system had always been recognized
in Europe, where ties and timbers intended for creosoting were
stacked up for nine to ten months to season.

The Bethell was the original creosote process and it is yet the
standard. The best results have been obtained through its
instrumentality. But the fact that the process as first detailed
abroad is suitable only for the treatment of seasoned woods, and
the further fact that large amounts of oil are required, have led
to some modifications.

In the United States the principal demand is for the treatment
of green or imperfectly seasoned woods and with this in mind,

REFERENCES. — "Antiseptic Treatment of Timber," Boulton (Proceed-
ings Institution Civil Engineers, London, 1884); "Preservation of Timber,"
Report of Committee (American Society of Civil Engineers, 1885); "Pres-
ervation of Structural Timber," Weiss (1915); etc., etc.

364 ORGANIC STRUCTURAL MATERIALS

in 1872, Hayford suggested that woods be prepared by steam
instead of by drying. With the difference noted the Bethell and
Hayford processes are alike. The latter title is now seldom used,
while the title " Bethell Process " has been extended in the United
States to include the preliminary steaming of green woods, as
well as the preliminary drying of seasoned woods.1

The London, Brighton & South Coast Railway Company
apply creosote under a specification as follows:2

"The sleepers, when sufficiently dry, are to be placed in a wrought-
iron cylinder, and, when closed, a vacuum is to be created by air pumps.
The creosote, at a temperature of not less than 120 degrees Fahr., and
not more than 150 degrees, is to be allowed to enter the exhausted cylin-
der, and afterwards is maintained there by pumping at a pressure of
not less than 120 pounds to the square inch. The sleepers are to be kept
under this pressure until each sleeper has absorbed at least three gallons
of creosote on the average, the quantity to be ascertained by weighing.
Any charge of sleepers not giving the average impregnation of at least
three gallons is to be returned to the cylinder for further treatment."

The Eppinger & Russell Company employ details as follows:
Wood is steamed at about twenty-five pounds pressure. The
steam is succeeded by vacuum of about twenty-eight inches; the
oil is then admitted and held under a pressure of from fifty to two
hundred pounds, as the quality of the wood may indicate. Such
minor changes are made from time to time as appear to be sug-
gested from experience.3

A specification prepared by the Southern Creosoting Company
of Slidell, Louisiana, is as follows:4

"Steaming Process. — The seasoning of the timber shall be accom-
plished by the direct application of live steam admitted into the treating
cylinders. The steam gauge pressure in the cylinders shall be regulated
according to the dimensions of the timber. During the process of steam-
ing the cylinder must be frequently drained by a valve located at the
lowest possible point. The steaming must continue from three to fif-
teen hours, according to the size of the lumber and the quantity of oil
to be injected into it. At the end of the steaming period a vacuum shall
be created in the cylinder, the temperature being at all times maintained

1 "The Hayford Process and Apparatus for Preserving Timber," Andrews
(Journal of the Franklin Institute, February and March, 1878).

2 In force February, 1916.

3 In force December, 1915.

4 In force January, 1916.

PRESERVATIVES APPLIED WITHIN WOODS 365

above the boiling point. The vacuum must continue until the gauge
shows a reading of from twenty-two to twenty-six inches, and to be kept
at that reading until no moisture comes from the bottom of the cylinder.

"After the material has been thoroughly seasoned and it has been
ascertained that no sap or moisture remains in the cylinder, the oil shall
be admitted at a temperature of not less than 120 degrees Fahr., which
temperature shall be raised to not less than 185 degrees Fahr. under a
pressure of not less than 125 pounds per square inch. The force pump
producing this pressure shall be kept in operation until the established
system of measurement shows the wood to have absorbed the desired
quantity of oil.

"The pressure shall then be released and the timber completely
treated shall be immediately removed from the cylinders."

The American Telephone and Telegraph Company applies
creosote to timber other than Douglas fir under the very complete
specification that follows.1 The specifications do not cover the
treatment of crossarms:

''General. — These specifications describe the processes to be used in
impregnating timber, except crossarms, with dead oil of coal-tar and are
intended to include all instructions necessary for the proper performance
of the work.

" Testing Facilities. — The manufacturer shall provide and install such
apparatus as is necessary to enable the inspector to determine that the
requirements of these specifications are fulfilled. It is suggested that
recording temperature and pressure instruments be provided.

" Workmanship. — All material shall be of the best quality unless other-
wise specified herein and all workmanship shall be sound and reliable in
character and of the best grade.

Materials

"Timber. — The timber subjected to the creosoting treatment shall
conform to the requirements of the specifications and drawings furnished
by the telephone company. All timber shall be framed, shaped, and
bored before treatment.

"The material in each charge shall be in approximately the same con-
dition so far as air-seasoning is concerned, and under no circumstances
shall green, partially seasoned, or seasoned timber be treated together
in the same charge.

"Two kinds of timber, for example yellow pine and black gum, shall
not be treated together. When the southern yellow pines are treated,
longleaf and Cuban pine shall not be included in charges with shortleaf
and loblolly pines.

1 Specification 3,156, April 3, 1909 (in force April, 1912).

366

ORGANIC STRUCTURAL MATERIALS

"Only one class of material shall be treated in any one charge, for
example, poles and ducts shall not be treated together.

Dead Oil of Coal-tar. — The dead oil of coal-tar used in impregnating
the timber shall conform to the requirement of the American Telephone
and Telegraph Company's Specifications for Dead Oil of Coal-tar or
Coal-tar Creosote. The telephone company shall have the right to take
samples of the oil whenever its inspector shall elect. The sample of oil
so collected shall be tested wherever the telephone company shall elect.

"Quantity of Oil. — All timber shall be so impregnated with dead oil
of coal-tar that the average impregnation of the material in each cylinder
load shall not be less than the quantity of oil called for in the specifica-
tions for the material or in the contract. The volume of timber and
the quantity of oil absorbed shall be determined by the inspector. The
inspector shall have access to all records of treatment.

" Excess of oil in one charge shall not be offset against a shortage of
oil in another charge.

"The treating plant shall be equipped, to the satisfaction of the tele-
phone company, so as to allow a close determination of the amount of
oil injected into the timber.

"The quantity of oil injected into the timber, as determined by the
volume of oil withdrawn from the measuring tanks, shall be based on
the standard temperature of 100°F., and the quantity increased by an
amount equal to 0.00044 of the required volume at 100°F. for each
degree Fahrenheit of oil temperature above the standard temperature
of 100°F.

11 Treatment

"General. — The treating cylinder shall not be opened during the proc-
ess of treatment.

"Classification. — For the treating process timber shall be classified as
heavy or small.

"Heavy timber shall be understood to include poles and stubs; small
timber shall, unless otherwise specified, include all other timber, except
crossarms, ordered by the telephone company.

"Steaming and Heating Process. — Steam when used shall be main-
tained at a uniform pressure and temperature in the treating cylinder
as indicated in the following table :

Steam i

pressure

Steam tempera-
ture

Not less than

Not greater than

Not greater than

For heavy timber.

17 pounds

20 pounds

259°F.

For small timber. . .

12 pounds

15 pounds

250°F.

PRESERVATIVES APPLIED WITHIN WOODS

367

"The temperature readings shall be taken by means of standard ther-
mometers placed in the treating cylinder so that the bulbs thereof are
within the shell.

"At the beginning of the steaming process the exhaust valve shall be
open and shall not be closed until a steady flow of steam escapes through
the valve. The duration of the steaming process shall be timed from
the closing of the exhaust valve. The exhaust valve shall be opened
and the condensation blown off at intervals during the steaming process.

"The duration of the steaming process shall be as directed by the
inspector and shall depend upon the condition and character of the tim-
ber, but shall in no case be carried to such an extent as to injure the
timber. The timber shall not be steamed in excess of the interval given
in the following table:

Green or very
wet timber

Partially
seasoned
timber

Seasoned
timber

For heavy timber

8 hours

5 hours

0 hours

For small timber

5 hours

3 hours

0 hours

"Seasoned timber shall not be steamed, but shall be heated in the
treating cylinder. The temperature within the cylinder shall be main-
tained by means of the closed heating coils at a temperature of about
150°F.

For heavy timber for at least 2 hours.

For small timber for at least 1 hour.

"Exhaustion Process. Green and Partially Seasoned Timber. — When
the steaming process shall have been completed the steam shall be blown
off and the treating cylinder exhausted to a vacuum of at least twenty-
four (24) inches at or near sea level, or proportionately less at higher
altitudes. The vacuum shall be maintained at the above minimum for
a period: for heavy timber, of not less than 2 hours; for small timber,
of not less than 1 hour; and if necessary thereafter until the condenser
discharge is clear. During the exhaustion process the temperature
within the treating cylinder shall be maintained, by means of saturated
steam in the closed heating coils, above that at which water would boil
at that degree of vacuum.

"Exhaustion Process. Seasoned Timber. — With seasoned timber it is
not required that a vacuum shall be drawn after the heating process
and before' the filling process, provided that the specified amount of
dead oil of coal-tar is in the timber on its removal from the treating
cylinder.

"Filling Process. — After the exhaustion process, the cylinder shall be
completely filled, as rapidly as possible, with dead oil of coal-tar and
in no case shall the flow of oil into the treating cylinder be stopped

368 ORGANIC STRUCTURAL MATERIALS

before the overflow of the cylinder. Pressure shall then be applied
until the specified amount of oil has been forced into the timber.

"The total amount of oil forced into the timber shall be determined
from the initial reading on the measuring tanks and the readings on the
measuring tanks after the oil in the cylinder at the conclusion of the
pressure process, including all drip from the timber, has been returned to
the measuring tanks.

"The oil at introduction into the cylinder shall have a temperature
of not less than 140°F. and not more than 175°F. The oil in the meas-
uring tanks shall be maintained at a uniform temperature during the
filling process.

''Subsidiary Specifications. — The following specifications of the
American Telephone and Telegraph Company form a part of these
specifications :

" Specifications for Dead Oil of Coal-tar, or Coal-tar Creosote.

"Specifications for Analysis of Dead Oil of Coal-tar, or Coal-tar
Creosote."

The specification adopted by the American Railway Engineering
Association is given on page 448 of the 1911 Manual published by that
organization.

The Burnett Process. — This process, which was patented by
Burnett in 1838, depends upon the use of zinc chloride. The
immediate value of this salt as an enemy of wood-destroying
fungi is about equal to that of creosote, but because the salt
dissolves readily in water, the results are not as lasting. Neither
is it known that zinc chloride repels the attacks of teredos and
other shipworms.

The method of impregnation is similar to that employed in the
Full-cell Creosote Process. The wood is steamed, partly dried in
a vacuum of from twenty to twenty-five inches, and then treated
with warm zinc chloride solution which is held under pressure
until the required absorption has taken place. Here as elsewhere,
results are influenced by attention paid to details. The object is
to transfer the required quantity of antiseptic to the interior of
the wood, and to secure the greatest practicable uniformity of
distribution without injuring the wood.

REFERENCES. — "The Artificial Preservation of Railroad Ties by the Use
of Zinc Chloride," Curtis (Transactions American Society Civil Engineers,
Vol. XLII, 1899); "Handbook of Timber Preservation," Rowe (Author's
Edition, 1900); "On the Determination of Zinc in Treated Timbers,"
Fulks (American Railway Engineering Association, Bulletin No. 65, 1905);
"Visual Method for Determining the Penetration of Inorganic Salts in
Treated Wood," Bateman (United States Forest Service, Circular No.
190) ; etc., etc.

PRESERVATIVES APPLIED WITHIN WOODS 369

The Burnett Process is essentially a tie-preserving process and
is not suitable for timbers that are to be exposed in marine
positions. It is cheaper than creosoting, and particularly useful
with ties which are to be exposed in climates and surroundings
that are not too wet. Under such conditions the life of the ties is
frequently doubled. A field of usefulness is with inferior woods
that must now, with the scarcity of better kinds, be employed.
It is needless to urge that prevention of decay should be adjusted
as far as possible to the natural mechanical life of the tie and that
expensive treatments are not warranted with ties that wear out
before they rot. The Burnett and Full-cell Creosote Processes
were compared by Chanute as follows:1

"An average life of ten to twelve years is being obtained by the use
of zinc chloride in this country. It would be possible to obtain a life
of fifteen to thirty years by the use of creosote, but it will be seen from
the figures given2 that this would cost three to four times as much as
zinc chloride.

" We must be content, therefore, either to allow our cheap ties to decay
in the good old way, or to adopt for the present some of the cheaper
and inferior methods which will produce shorter lives than obtained in
Europe."

The Burnett method is much used in the United States and
Europe.

THE EMPTY-CELL CREOSOTE PROCESSES.— The Riiep-
ing and Lowry processes have for their object the wide diffusion
throughout the wood of limited quantities of creosote. In both
cases air-seasoned wood is preferred, although in the Riieping
Process green woods can be and frequently are treated after they
have been prepared by steaming and vacuum as in the Hayford
Process.

The Riieping Process. — This process is characterized by the
use of compressed air, which is admitted to the cylinder and held
there until the fabric of the wood is thoroughly penetrated. At

1 "The Preservation of Railway Ties in Europe," Chanute (Transactions
American Society of Civil Engineers, Vol. XLV, p. 509).

2 "The Artificial Preservation of Railroad Ties by the Use of Zinc Chlo-
ride," Curtis (Transactions American Society of Civil Engineers, Vol. XLII,
pp. 288-374).

370 ORGANIC STRUCTURAL MATERIALS

this stage the wood is sometimes described as being " filled with
compressed air." Creosote is then admitted under a slightly
higher pressure, the air in the cylinder gradually escaping. The
pressure is then raised to about one hundred and fifty or more
pounds, at which point it is made to remain for a sufficient time.

Finally, the pressure is released when the air which was first
introduced within the wood expands and drives out much creo-
sote. A vacuum which follows assists in this result. Consider-
able oil thus recovered is referred to as "kick-back." The pene-
tration obtained during the Rtieping Process may be as deep as
that secured during the Bethell Process, while at the same time
much less creosote is required. The Riieping Process is used
extensively in the United States and in Europe.

The Riieping Process is detailed by a railway company1
located in the southeastern part of the United States, as follows :

"Compressed air is pumped into the main cylinder which is filled
with timber, and into the Riieping cylinder which is filled with creosote.
This integral air pressure, which amounts to from twenty-five to seventy-
five pounds per square inch, is the means by which the final amount of
oil to be retained in the wood is regulated.

"The cylinder containing the timber and the Riieping cylinder con-
taining the creosote being under the same pressure, the oil in the Riieping
cylinder is directed into the main cylinder without decreasing the pres-
sure in the latter cylinder. Additional pressure, amounting to about
one hundred pounds, is now applied to the contents of the main or heat-
ing cylinder by means of pressure pumps. If the initial pressure was
sixty-five pounds, the pressure would now be about one hundred and
sixty-five pounds to the square inch. The amount of the pressure and
the duration of the period during which it is applied are determined by
experience.

"On the completion of the pressure period a valve is opened and the
pressure released. The one hundred pounds of pressure last applied is
itself first released after which the initial pressure escapes. The initial
pressure coming from the interior of the timber drives out the loose creo-
sote and leaves only the walls of the cells coated. A vacuum is drawn
and the charge is released."

The Lowry Process. — This process differs from that just
described in that compressed air is not employed. The wood
is first air-seasoned and the air present naturally in wood thus
dried is assumed to be sufficient to drive out superfluous creosote

1 The Charlotte Harbor and Northern Railway Company at Hull, Florida.

PLATE XIX. PLANT FOR CREOSOTING LUMBER

(Photographs by Eppinger & Russell Company.)

(Facing page 370.)

PRESERVATIVES APPLIED WITHIN WOODS 371

after the antiseptic has been introduced by methods similar to
those used in the Riieping Process. The Lowry Process also
aims to secure a deep penetration of creosote with less oil than is
required by the Bethell or Full-cell Process. The Lowry Process
is extensively used throughout the United States.1

THE ZINC-CREOSOTE PROCESSES.— The Rutgers, Card,
and Allardyce Processes make use of zinc chloride and creosote.
The first-named antiseptic is used because it is cheap, and the
last is used because, in addition to its intrinsic value, it retards
the escape of the zinc chloride. The two preservatives are forced
into the wood while mixed together in the form of an emulsion,
or they are introduced separately one after the other.

In the Rutgers Process, the zinc and creosote are introduced
while mixed together by means that resemble those employed to
introduce pure creosote during the Bethell Process. In Ger-
many, where every attention is paid to detail, the Rutgers Pro-
cess has caused pine ties to last for from fifteen to eighteen years.
The process has been practised successfully for about forty years.

The Card Process differs from the Rutgers Process in the means
used to mingle the antiseptic liquids. These are first mixed
together by forcing air through perforated pipes located at the
bottoms of the mixing tanks; the agitation is then continued by
means of centrifugal pumps. Further details resemble those
followed in the Bethell Process. The best results are obtained
with air-seasoned woods.

The Allardyce Process is planned so that the preservatives are
introduced separately one after the other. First, a solution of
zinc chloride is introduced into the wood by an air pressure of
about 130 pounds per square inch. The cylinder is then drained
and is refilled with creosote which is finally subjected to a pres-
sure of about 180 pounds per square inch. The penetration of
creosote is not great and the process itself is not extensively used
at the present time.

THE ZINC-TANNIN PROCESS.— In the Wellhouse Process
glue and tannin are used in attempts to retard the escape of
zinc chloride. Otherwise, the Wellhouse and Burnett prac-
tices resemble one another. Both depend upon the preservative
properties of zinc chloride; but in the Wellhouse Process glue and
tannin, acting upon one another, form inert solids which obstruct
the escape of the soluble zinc chloride. The Wellhouse Process is

1 " Preservation of Structural Timber," Weiss (1915, pp. 59-60).

372 ORGANIC STRUCTURAL MATERIALS

comparatively cheap and has succeeded in greatly increasing the
length of life of some perishable woods. On the whole, however,
the results secured from this process have not been as satisfactory
as were at first hoped for.

THE BOILING PROCESS. — This process is largely used for
the treatment of Douglas Fir. Either green or seasoned woods
can be treated. The Boiling Process is described by Sherfesee as
follows:1

"This process is used principally on the Pacific Coast, and for Douglas
Fir, an exceedingly difficult wood to treat. The timber, usually green,
is placed in the treating cylinder, which is then filled with creosote
heated to a temperature slightly above the boiling point of water. This
hot bath is continued for from several hours to more than two days, de-
pending upon the size and condition of the timber. During the bath
much of the water in the sap is driven off, together with the volatilized
light oils. These vapors are caught in a condenser, the water is decanted
off, and the oil is run back into the receiving tank to be used over again.
Finally, an oil pressure of 100 to 125 pounds is applied, and, at the same
time, the temperature of the oil is allowed to fall, thus forcing the pre-
servative into the timber."

THE CREO-RESINATE PROCESS.— As first detailed, wood
was subjected to dry heat, after which a vacuum was drawn.
Creosote, resin and formaldehyde were then applied while mixed
together. It is said that woods were hardened as well as pre-
served by this process, which has been extensively employed in
the preparation of paving blocks.2

The Boucherie Process. — Cylinders were not employed in this process.
The inventor first attempted to distribute preservative substances
through the wood of standing trees by introducing the substances into
the sap of the trees, and the process as patented called for the presence
of sap or other moisture within the wood that was to be treated.

Several methods were ultimately suggested by Boucherie for forcing
solutions into the woods after the trees had been cut down.3 In the
principal one, pressure was obtained by elevating the tank that contained
the solution. The tank thus elevated was connected with a cap designed
to fit over one end of the timber, and the antiseptic solution was passed

1 "Wood Preservation in the United States" (United States Forest Ser-
vice, Bulletin No. 78, p. 15).

2 Transactions of the American Society of Civil Engineers, Vol. XLIV.

3 "Wood Preservation," Flad (United States Forestry Bulletin No. 1,
p. 69).

PRESERVATIVES APPLIED WITHIN WOODS 373

from the tank through the timber until the moisture that emerged from
the opposite end of the timber was proved by tests to be nearly pure.

The introduction of better methods led to the practical abandonment
of the Boucherie Process even in France, where it was most practised.
Criticisms were that the work had to be done in the forest, and that
every stick of timber had to be handled separately. This would have
prevented the method from being used upon a large scale, even if the
results accomplished by it had been more satisfactory.

Experiments made more recently to determine whether zinc chloride
solution and creosote could be forced into single pieces of wood by pres-
sure obtained by the use of ordinary hand pumps, yielded results that
were neither uniform nor satisfactory.1 In this case, a steel cap was
made to fit over the butt of the timber. The cap was connected with
the pump and with the reservoir containing the hot preservative.

Although the Boucherie process can be used with other antiseptics,
it is generally associated with copper sulphate.

SOME MISCELLANEOUS PROCESSES.

Charring. — Charring is an internal as well as an external process.
Not only does the shell of charcoal protect from bacteria, but the wood
beneath is more or less sterilized. Charring is defective because its
field of application is limited, and because so much of the wood is
destroyed.

Vulcanizing. — Destructive heat was not concentrated as in charring,
but less heat was diffused throughout the wood by means of compressed
air. The result was accomplished by placing the wood in cylinders and
then subjecting it to dry heat with pressure. Chandler reported favor-
ably upon this process, which is no longer practised upon a large scale.
Vulcanized ties were used for some time on the New York elevated
railways.

The Bobbins Process. — This now historic method, from which much
was expected, was designed to use a minimum of creosote in the form
of vapor. The high temperature necessary to volatilize good creosote
injures wood, and the process, which failed in practical tests, was long
since abandoned. The Robbins Company was highly capitalized. A
convention held in ttye Astor House in New York in 1869 was attended
by delegates from Maine to California who referred to the inventor as
a " great public benefactor." The expectations of those interested in
this process were not realized.

The Seeley Process. — The charge was placed in a bath of hot creosote
which was then more or less abruptly replaced by cold creosote. It was
believed that the heat volatilized the sap in the wood, and that the

l" Prolonging the Life of Telephone Poles," Grinnell (United States
Department of Agriculture, Year Book, 1905).

374 ORGANIC STRUCTURAL MATERIALS

vacuum caused by the condensation of the vaporized sap when the cold
creosote was introduced would draw quantities of creosote into the wood.
The process was conducted in closed cylinders. It is interesting to com-
pare it with the open-tank process.

The Powell Process. — Timber is boiled in a strong solution of sugar.
It is claimed that seasoned woods are cured and the toughness is
increased.

The Thilmany Process. — An injection of copper sulphate was followed
by a bath of chloride of barium. An interchange of the constituents
of these two salts, if brought together in the proper proportions, left
the timber impregnated with chloride of copper and sulphate of barium.
The insoluble sulphate of barium was relied upon to prevent the removal
of the soluble chloride of copper.

The Hasselmann Process. — The wood was boiled in a solution of cop-
per sulphate, iron sulphate, aluminum sulphate, and a small quantity
of kainit. This method was first used by the Bavarian Government.

The Ferrell Process. — The salts selected recombine in the wood as in
the Thilmany Process. The impregnation is manipulated from the ends
of the pieces as in the Boucherie Method.

The Creoaire Creosote Process. — This process, which is designed to
overcome the tendency of creosote to lodge near the surfaces of timbers,
consists in subjecting woods, that have been creosoted, to a final air
pressure, by means of which the creosote is driven in from the surface
and deposited more evenly throughout the mass.1

WOODS THAT ARE TO RECEIVE TREATMENT

Some woods last naturally without treatment longer than other
woods will last after they have been treated.

It is often well to consider the economy of treating non-durable
woods that are tough and strong and that respond to treatment.
For example, beech is desirable structurally save for the fact that
it rots quickly in exposed places; yet it receives antiseptic solu-
tions better than white oak receives them and, after being suit-
ably processed, will last for a long time.

The results obtained with beech by the French are often quoted.
Beech ties are seasoned for at least six months and are then kiln-dried
for from sixty to eighty hours to expel the remaining moisture and to
warm the pieces so that they will not chill the creosote. Each tie then
receives an average of sixty pounds of creosote. Experience has led to

1 Yet occasionally practised by the International Creosoting and Con-
struction Company, Galveston, Texas.

PRESERVATIVES APPLIED WITHIN WOODS 375

the belief that such ties will last in the track for at least thirty years,
and that they will finally fail by wear rather than by rot.1

The ability of wood to receive preservative treatment is influ-
enced by the character and arrangement of its cell-elements.
The presence of tyloses in the large vessels or pores of such woods
as white oak and black locust interferes correspondingly with the
treatment of these woods. As a rule, sapwood is more open to
the passage of preservatives than is heartwood. Large quantities
of yellow pine are now treated with preservative, while von
Schrenk suggests, beech, maple, birch, red and swamp oaks, gum,
hemlock, and even cottonwood as American species that should
receive consideration in this connection.2

Individual pieces, as well as species, vary from one another in
receptivity. For this reason, as far as possible, charges should
be made up of pieces that are nearly similar to one another. Re-
fractory pieces should receive such special attention as is neces-
sary to overcome extra resistance.

The tendency of preservatives to lodge near the surface of
pieces should be recognized, and, whenever possible, timber
should be cut, shaped, or fitted before it is treated.

CONCLUSIONS

1. Cheap woods, or those used in inexpensive or unimportant
constructions, are seldom treated with preservatives at the present
time in the United States. Woods are now treated only when
they become costly, or when they are to be used in works that
do not permit renewals or repairs at reasonable prices.

2. Zinc chloride and creosote are used more than all other
wood preservatives.

3. Zinc chloride is soluble in water, and therefore cannot be
used with woods that are to be exposed in marine positions.
Neither is it known that it protects woods against marine and
terrestrial woodborers. The principal field of zinc chloride as a
wood preservative is with railway ties that cannot be economically
treated with the more expensive creosote.

4. Experience has shown that wood can be protected against
rot, and against marine and terrestrial woodborers, by the intel-
ligent use of sufficient quantities of good creosote.

1 " Preservation of Railway Ties in Europe," Chanute (Transactions
American Society of Civil Engineers, Vol. XLV, 1901).

2 United States Department of Agriculture, Yearbook, 1903 (p. 42).

376 ORGANIC STRUCTURAL MATERIALS

5. Creosote is complex and variable. It should therefore be
purchased from reputable dealers, and its properties should be
controlled by specifications.

6. The details of wood-preserving processes call for knowledge,
skill, and integrity on the part of the operator. A poor method
well detailed may afford better results than a better method
poorly detailed.

CHAPTER XV

PROTECTIVE METHODS — EXTERNAL TREATMENT. OILS,

PAINTS, VARNISHES, AND OTHER COATINGS. THEIR

APPLICATION TO SURFACES OF WOOD

Outside coatings not only protect from outside conditions, but
at the same time seal up any moisture that may be present within
the wood. Moisture thus enclosed makes rotting possible.
Furthermore, since oil and water do not mix, paints will not be-
have in a satisfactory manner if applied to woods that are wet.
It therefore follows that no coating of any kind should be ap-
plied to wood that is not dry and well seasoned.

External coatings, which are of many kinds, are employed both
to beautify woods and to protect them against marine life and
abrasion, as well as moisture and the decay caused by bacteria
and fungi. Woods may be enclosed by metal, plaster, masonry,
and charcoal, as well as by paints and varnishes.

A protective coating is not always decorative, but a decora-
tive coating always affords protection. Paint is a Material of
Construction, and its behavior in construction is quite as impor-
tant as its color or appearance. The durability of any coating
must generally influence that of the substance which it covers.

The cost of the most expensive coating is generally less than
the present cost of the labor required to apply it, and the more
intricate the surface, the greater the disproportion between the
bill for labor and the bill for material. True economy consists

REFERENCES. — "White Lead and Zinc Paints," Petit (Scott, Greenwood
& Sons, London, 1907); "Lead and Zinc Pigments," Holley (Wiley & Sons,
1909); "Linseed Oil," Ennis (Van Nostrand, 1910); "Chemistry of Paints,"
Friend (Longmans, Green & Company, 1910); "Materials of the Painters'
Craft," Laurie (Foulis, London and Edinburgh, 1910); "German and
American Varnish-Making," Bottler and Sabin (Wiley & Sons, 1912);
"Technology of Paint and Varnish," Sabin (John Wiley & Sons, 1917);
Files of Painters' Magazine; Oil and Color Trades Journal; Proceedings of
the Paint and Varnish Society (London); Farben-Zeitung (Berlin); Engineer-
ing News; Engineering Record; Railway Gazette; Transactions American
Society for Testing Materials; Journal Industrial and Engineering Chemistry
(American Chemical Society).

377

378 ORGANIC STRUCTURAL MATERIALS

in selecting the paints and other materials that last longest, so
that there will be the longest possible intervals between renewals.

Woods that are to be coated may be within doors, protected
from the weather, or out of doors, exposed to the weather.
Polished surfaces, enamels, fine varnishes, and ordinary oil
paints are common in the case of interior surfaces, while oil paints
predominate in connection with exteriors, which are much simpler
in their requirements. Ships, passenger cars, carriages, furni-
ture, and some other constructions require special methods, that
are distinct from the simple protection of ordinary woodwork
by paint.

The behavior of a paint when applied to unpainted wood
differs from its behavior when applied to unpainted metal.
Paint sinks into the pores of clean, dry wood to an extent that is
not possible with metal. Woods themselves differ in receptivity,
the loose-grained species absorbing the paint more readily than
do those with the closer grain.

PAINT. — A paint is a mixture of a vehicle and a pigment.
Although oil, varnish, glue, or any other fluid that will cement
solid particles together in a satisfactory manner, may be em-
ployed as a vehicle, linseed oil is the common vehicle in the
paints that are used in construction.

A pigment is a more or less inert base that will join with oil
to form a paint. The function of the vehicle is to cement and
give strength, while the pigment serves to afford solidity, color,
and hardness. White lead, zinc white, and the iron oxides are
among the basic pigments that are commonly applied to woods.

A paint is a mechanical mixture or suspension, rather than a
chemical combination. Paint, as a substance, fails when changes
take place in the dried vehicle or binding material. As a coating,
paint may fail by abrasion, as by rain or dust, by contraction,
expansion, and cracking, or because it has been applied to surfaces
that were not clean and dry.

VARNISH. — Varnish is obtained by dissolving resins in oil or
spirit. Oil varnish differs from spirit varnish, in that oil takes
a permanent place as part of the dried film; whereas spirit simply
dissolves the varnish resins and then evaporates from them.
The mixture that results, when pigment is added to varnish, is
known as an enamel or varnish paint. In such paints, varnish,
instead of oil, is the vehicle.

Varnishes are solutions, and thus differ from paints, which

OILS PAINTS VARNISHES AND OTHER COATINGS 379

are mechanical mixtures. A paint may or may not be prepared
by the consumer, but a high-grade varnish, which can be manu-
factured only by a chemical process, can seldom be prepared by
the consumer.

The subject is one that must be considered in three parts,
namely: the materials of which paints and varnishes are com-
posed; the methods used to apply paints and varnishes; with the
influence of such methods upon durability; and the preparation
of woods to receive paints and varnishes.

MATERIALS USED IN PAINTS AND VARNISHES

OILS. — All oils used in constructions may be divided into
three groups; solidifying oils, that can be used in paints because
they change, upon exposure, into tough, leathery solids; non-
solidifying oils, that are not used in paints and that are men-
tioned in this place only for completeness; and volatile oils or
spirits, that serve to dissolve or to dilute paints.

Solidifying Oils and Driers. — Solidifying oils do not dry in
the ordinary sense of the word, because of loss of water, but
because of chemical changes which they undergo when they are
exposed to the air at ordinary temperatures and in thin sheets.
Oil from walnuts and oils from other sources possess this property,
but oil from common flaxseed is preferred for ordinary condi-
tions, both because it affords good results, and because it can be
obtained in commercial quantities at reasonable cost. The
Chinese Tung Oil is also very valuable.

Linseed Oil. — Linseed oil is drawn from the seed of the flax plant by
hot or cold pressure, or by solvents, and is then treated to a process of
purification. The tough, elastic, semi-translucent solid, into which this
oil changes upon exposure, is known as linoxyn or oil-rubber.1 This
solidified or " dried" compound, although occupying smaller space, has
increased in weight from ten to eighteen per cent., because of oxidation
or other changes that have taken place.

Pure, raw linseed oil requires some days to solidify. This time may
be reduced by boiling the raw oil with certain metallic salts, or by adding
compounds, known as driers, to the raw oil. In each case the object

1 Although linoxyn or oil-rubber is not nearly as elastic as true rubber, it
has been used with true rubber. The "drying" or solidification of linseed
oil has presented many problems and is described in "Some New Points in
Paint Technology," Sabin (Laboratory Bulletin, January 31, 1911). See
also "Linseed Oil," Ennis (D. Van Nostrand Company). ,

380 ORGANIC STRUCTURAL MATERIALS

of the metallic salt, or other drier, is to act, as a catalyzer, by transferring
oxygen from the air to the oil. Raw oil with added drier is often referred
to as boiled oil, even although it has not been boiled.

Raw linseed oil penetrates better and is more durable than boiled oil,
or oil to which a drier has been added; but, since the weather cannot be
relied upon to remain clear long enough for raw oil to dry, drying should
be hastened by adding the smallest possible quantity of drier to the
raw oil.

A product prepared by heating refined linseed oil, without driers,
until it has become thick and viscous, but not jelly-like, is known as
lithographic oil. This product, the use of which is rapidly increasing,
is employed in varnishes as well as in printers' ink.

Tung Oil, China Wood Oil, Elaeococca Oil— This oil, which is de-
rived from the seeds of the Tung Oil tree (Akurites fordii},1 has long
been employed in the Orient, for waterproofing and other purposes.
The Chinese have used it to waterproof their umbrellas, and to prepare
paper so it could be used for glazing.

Tung Oil is a drying oil of the very first value; and its position as a
Material of Construction is more and more realized in the United States,
to which country large quantities are now brought every year. Within
a few years it has largely displaced the use of linseed oil in the manu-
facture of certain varnishes, that are valued because they dry more
rapidly than linseed oil varnishes, because they are not liable to crack,
and because they ultimately present tough, durable, alkali-resisting,
flat, that is not glossy, surfaces. Tung Oil. is used in flat wall finishes
and, in mixtures, to waterproof cements. The oil possesses a strong,
characteristic odor which is largely removed during the cooking and
manipulating that it receives while being manufactured into varnish.
Sandalwood oil, cedar oil, citronella, and other chemical compounds
are sometimes used in the attempt to smother this odor, but they do
not succeed because they so largely evaporate.

Driers. — Driers should be purchased from reputable dealers, and
should be used in the smallest possible quantities. Sabin states that
although drier injures paint, yet "the lack of it is fatal, for paint must
dry within a reasonable time." Driers carry oxygen throughout the
depth of the coat. Oxides of lead and manganese are fundamental
driers. Chemically, driers are catalytic agents.

A japan drier cannot be definitely distinguished from other driers,
although the name japan usually refers to driers that, with other proper-

1 "The China Wood Oil Tree," Fairchild (United States Bureau of Plant
Industry, Circular No. 108); Files of Oil, Paint and Drug Reporter; "Index
of Patents, Technology, and Bibliography of China Wood Oil (Tung Oil),"
George H. Stevens and J. Warren Armitage (Published by Authors at
Irvington and Newark, New Jersey, 1914).

OILS PAINTS VARNISHES AND OTHER COATINGS 381

ties, are characterized by the fact that they will harden into varnish-like
films. Japan varnishes are called after the country in which they orig-
inated. The name japan may apply to a drier or to a varnish. Most
driers are " proprietary mixtures."

Non-solidifying Oils. — Oils of this class are mentioned for
completeness. These oils are not used in paints, but some semi-
solidifying oils — that respond to the action of driers — are used
for this purpose, particularly in prepared paint mixtures. Non-
solidifying oils are used as lubricants which serve to fill the minute
inequalities that exist on the surfaces of all machine materials
and, therefore, should not under any circumstance solidify
or "gum." Although lubricating oils are manufactured princi-
pally from petroleum, the group also includes whale, olive, lard,
and many other oils.

Volatile Oils and Spirits. — Turpentine, benzine, benzole, and
alcohol are the volatile oils and spirits most used with paints
and varnishes. Turpentine contains a small proportion of
gummy cementing substance that eventually becomes part of
the finish. Benzine and alcohol vaporize completely without
leaving residues.

The excessive use of volatile solvents injures paints because
they thin the oils upon which paints depend for their strength.
A thinned paint spreads easily and covers a greater surface, but
the dried film is correspondingly thinner. A thinned paint dries
rapidly, but is less durable. Turpentine may cause direct injury
to exactly prepared paint mixtures, and should seldom normally
be employed in any outside or weather coat.

Volatile solvents are of advantage when paints are to be
applied to close-grained woods or to already existing hardened
paint. Pure oil is too thick to sink sufficiently into many woods,
while old paint is often so hard that paint without turpentine
will not adhere.

PIGMENTS. — A pigment contributes thickness, opacity,
hardness, solidity, and color. Oil binds the particles of pigment
together, as stones are bound in concrete, and pigment thickens
the oil. The hard particles of pigment assist the paint in
resisting abrasion.

Oil shrinks in drying; and the minute openings that are formed
would cause the coating to become porous, if it were not for the
particles of pigment used to fill them. The openings are very
small, and the pigment should be in correspondingly fine pow-

382 ORGANIC STRUCTURAL MATERIALS

der. Pigments are also relied upon to produce exact colors. ] The
principal pigments used in paints that are applied to woods are
white lead, zinc white, the iron oxides, and carbon.

White Lead.— Approximately 2PbC03.Pb(OH)2. This opaque,
heavy, white pigment is usually ground in a small quantity of oil and
sold as a paste, with which the necessary additional quantities of oil are
later mixed. White lead mixes well, works easily under the brush, and
is in every way the most satisfactory of the white pigments, although
less durable than some that are not white. Any tint may be produced
by adding the proper pigment to a body paint of white lead.

White lead ultimately degenerates into a form that permits a chemical
union to take place between it and the oil. This change takes place
much more rapidly in some cases than in others. White lead lasts longer
within houses, or in the country, than upon the outside of houses, or
in the city. White lead " chalks" very rapidly near the seashore.

White lead as a coat fails, as other coats do, by contraction and ex-
pansion, with resulting cracking and peeling, much of which can be
postponed by judicious mixing and application. In spite of defects, no
other white base has as yet been discovered that presents many of the
properties that render white lead so desirable.

Zinc White (ZnO). — Oxide of zinc is prepared by roasting metallic
zinc, 01; non-sulphurous zinc ores, and by permitting the vapors that
result in either case to combine with atmospheric oxygen. Zinc white
is lighter, harder, whiter, and less changeable than white lead; but it
requires more oil and does not spread as well as white lead; neither does
it adhere as well as that pigment. Three coats of white lead are usually
equal to five coats of zinc white. Zinc white and white lead may be
mixed together with advantage.

Barium Sulphate (BaS04). —Barium sulphate, barytes, or heavy spar,
is a heavy, brittle, white or light-tinted mineral that is capable of being
ground to a smooth, colorless, and chemically inert powder. It is often
affirmed that this substance is used as an adulterant; but, if this is so,
it does not greatly injure the paint. It is a cheaper base than are lead
or zinc pigments, but more coats are needed if the work is to present as
solid and opaque an appearance. The field for pure barium paints has
been limited.

1 The principal colors are produced by the following pigments :

White White lead, zinc white.

Black Lamp black.

Red Red lead.

Blue Ultramarine and Prussian blue.

Yellow Chrome yellow (lead chromate PbCrO4).

Green Chrome green (chromium sesquioxide).

Brown, red-brown, etc The siennas, umbers, etc.

OILS PAINTS VARNISHES AND OTHER COATINGS 383

A pigment should be opaque when it is wet. Even ground glass is
white and opaque as long as it is dry, but loses much of its opacity when
water is added. Barium sulphate, silica, and some other pigments
otherwise satisfactory lose much in this connection when compared with
white lead or zinc white, although otherwise some of them compare
favorably with those pigments.

There are other white pigments. As some clays are used for making
bricks, and others are used for making porcelains, so certain fine white
clays, known as china clays, are dried, ground and used as pigments.
Painters' silica and ground quartz are the same. Infusorial earth is
too fine to serve as a pigment, but has been used with more or less success
in fillers.

Red Lead (Pb304). — Red lead is made by oxidizing litharge (PbO),
and often contains from one per cent, to as much as twenty-five per cent,
of residual litharge. If much litharge is present, the linseed oil used in
mixing does not change to linoxyn; but, in this case, a lead compound
is apparently formed, and the oil and pigment harden, even although
shut in from the air. True red lead, that is, red lead without residual
litharge, and oil remain mixed for years without reaction. The United
States Government now specifies that the product known as "red lead"
must contain at least ninety-four per cent, of true red lead (Pb304),
and, for some uses, specifies ninety-eight per cent, or even a larger pro-
portion of true red lead. For under- water use red lead paints should
be mixed with genuine boiled oil. Red lead paints usually adhere to
iron with great tenacity. In the United States they are seldom used
on wood, except as it contains pitch; but in foreign countries red lead,
paints are often used, as other paints are used, to prime woods.1

Iron Oxides (Fe203 and variously hydrated oxides) . — Iron oxides may
be natural or artificial. Natural oxides result from hematites and limon-
ites. Those from the former mineral are harder, more costly to grind
and have more or less dull, brownish-red colors; while the softer limon-
ites present a series of somewhat lifeless yellows. Natural ores vary
greatly in their adaptability for use as pigments, chemical and physical
peculiarities being responsible for many grades and colors. Sienna is one
of the most brilliant of these ferruginous earth colors. The ochres and
umbers are also among them. Many natural ores are roasted before
they are ground. Umber when thus roasted is known as burnt umber.

Ordinary iron oxide paints are applied to both woods and metals.
They spread well, adhere firmly to wood and are very durable. They
are often preferred for large surfaces of wood that are to be covered
without much regard to color. Natural oxide paints are thus used on
freight cars, sheds and barns; while the finer, more attractive grades,
with some of those that are manufactured artificially, such as Tuscan

'See also "Red Lead," Sabin (Author's Edition).

384 ORGANIC STRUCTURAL MATERIALS

and Indian reds, are used upon residences and passenger coaches. The
field is a large one, and covers many grades or kinds of paint. Consider-
able quantities of oxide paints are used on steel structures, but such
paints for this purpose are giving place in many sections to carbon paints.

Carbon (C). — Carbon is a chemically inert substance, and is, therefore,
well adapted for use on iron. Lamp black, bone black, ivory black,
and graphite are the forms most used in paint. Carbon is seldom used
for the body of a paint to be applied to wood, but rather to tint such a
paint. It is largely used on metal. Lamp black, obtained from the
imperfect combustion of oil, is so bulky that a barrelful may weigh less
than twenty pounds. It requires more oil than other pigments, and
causes the paint to dry slowly, because of a small proportion of non-
drying oil which it frequently contains; pure lamp black is neutral, and
neither retards nor assists in the drying of the oil. A paint of lamp
black is one of the most durable of all paints.

Common graphite is laminated even after it has been ground into
small particles; and the manufacturers who use it state that the minute
particles arrange themselves when in paint, overlapping one another*
much as scales do upon the sides of a fish. Certainly, the particles are
very fine, and, regardless of their arrangement, the fact exists that some
paints of this class are very durable when laid upon iron. Most Ameri-
can graphite is mixed so intimately with the rock in which it occurs
that all of the rock cannot be removed. The silica present does not
appear to exert an injurious influence, however. Personal preference
must be exercised in choosing between the several forms of graphite
and lamp black paints.1

FILLERS. — Woods are more or less porous, and should be
primed before ordinary paints are applied to them, not only be-
cause paints of normal thickness cannot penetrate sufficiently to
attach themselves to woods, but also because a porous wood tends
to separate oil from pigment. The materials or mixtures used for
priming woods should accord with the coatings that are to be
applied later. Some mixtures will not adhere to others. Some-
times treatment that prepares for paint does not prepare equally
for varnish, and sometimes the same treatment does for both.
Oils, varnishes, thin paints, and prepared fillers are all used to
prime or to fill woods that are to be painted or varnished.

Woods that are to be painted should be primed or filled with thin
paint or pure linseed oil. Sabin states that "the best filler for wood
that is to receive ordinary oil paint is a coat of linseed oil." This sinks
into the wood and fills pores that might otherwise separate the oil from

1 An interesting material, in the nature of an amorphous graphite, which
is known as Acheson graphite, is manufactured from coal in electric furnaces
by the Sherwin-Williams Company.

OILS PAINTS VARNISHES AND OTHER COATINGS 385

the pigment when the full paint is later applied. It affords a base to
which the paint will adhere, and reduces the tendency to scale. Even
pure oil is sometimes too thick and heavy to sink into some woods, and
must be thinned by turpentine, in order to secure the proper degree of
penetration. When pure oil is used for priming, it often becomes hard
to determine whether some portion of the work has not been overlooked,
since there is but little difference in the appearance of unprimed parts
and parts primed with pure oil. The small quantity of pigment which
is commonly added to the oil gives color to the wood and removes this,
danger. Moreover, a little pigment assists by penetrating and filling
the pores of the wood.

A filler must be of such a nature that it will enter the wood, and then,
like the cement used by dentists, dry without shrinking. Proprietary
fillers are manufactured from silica, powdered bark, white lead, or other
substances combined with oil or varnish. Paste fillers are better than
liquid fillers, although the latter are more convenient.

Varnish itself is often used to fill woods that are to be varnished or
polished, and is an excellent, although expensive, filler. A priming
varnish should be thin, so that it will sink into the wood. Spar varnish
is often thus laid directly upon wood that is to be exposed to the weather.
Other coats of varnish are added until a firm and durable case is built up.

GUMS, RESINS AND VARNISHES.— True gums dissolve
in water, while true resins dissolve in oil or spirit. There are
also gum- resins, parts of which* dissolve in oil and parts in water;
and yet other exceptions, as india rubber, that dissolve in special
solvents, such as carbon bisulphide.

The name resin is seldom heard among varnish-makers, and,
commercially, the name gum is applied to many substances that
are really resins. True gums, such as gum-arabic, are not em-
ployed in the manufacture of varnishes that are to be used on
woods. A solution of true gum in water is called a mucilage.

Varnish resins have been roughly divided into fossil, semi-
fossil, and fresh-product resins. The origin of many fossil and
semi-fossil resins is uncertain. Amber is a fossil resin, while
dammar, mastic, and pine resins are among the fresh-product
resins.

Varnish resins may also be roughly divided into those used
with oil and those used with spirit. Kauri resin is thus preferred
in oil varnish, while shellac, dammar, and mastic are among
those used in spirit varnishes. The distinction between oil and
spirit as solvents has been noted in the section devoted to oils.

Most varnish resins are classified from the geographical or

386 ORGANIC STRUCTURAL MATERIALS

physical standpoint rather than from that of exact botanical
origin. As the wood known in trade as " cedar" may come from
several species, so varnish resins may be grouped by experts
without reference to the trees from which they came. Amber is
said to represent about fifty extinct botanical species. Time and
the process of mineralization have doubtless obliterated many
minor distinctions due to species.

Statements found in the literature of this subject are often
contradictory and misleading, but it is certain that characteristics
do exist that enable experts to classify these products and to
estimate their value for varnishes. Resins are often called by
different names in different places, but reputable manufacturers,
guided by their own standards, make selections that enable
them to present uniform and reliable varnishes.

Most fossil resins must be heated before the changes take
place that enable them to yield to the solvents employed by
varnish makers. Temperature, the proportions of resins and
solvents, the combinations of resins with one another, and other
details are important in the formation of tough, hard, durable,
and otherwise desirable mixtures.

Amber. — This hard and costly mineralized resin is found in small,
detached masses, in a few alluvial deposits. The total annual yield of
the important Baltic field is said to be less than one hundred and fifty
tons. The best pieces are used for ornamentation, beads, and the mouth-
pieces of pipes, while refuse, or black amber, is said to be manufactured
into special varnishes that can be used for the protection of oil paintings.

Copal. — This name is applied, without regard to botanical or geo-
graphical origin, to a wide range of resins used in the manufacture of
varnishes. When classified geographically, copals take name from ports
of shipment, and are described as Manila, Zanzibar, Sierra Leone, South
American, or other copals. They are also sometimes divided into true
and false copals, the 'former including the harder, more lustrous, and
refractory products, and the other, those that are softer, more variable,
and more easily dissolved. It will be seen that the name copal is a
general one, the value of which cannot be exactly told save from its
context.

Anime. — This is also a general name, which, although often seen,
means very little to modern varnish makers.

Zanzibar. — This is one of the hardest, most brilliant, and most per-
manent resins available to varnish-makers. With other resins, it enters
into the durable mixture known as "spar varnish;" and also into most
of the good varnishes designed for interiors. It is an ingredient of some

OILS PAINTS VARNISHES AND OTHER COATINGS 387

of the most satisfactory piano varnishes. Zanzibar resin is considered
wherever a high degree of hardness, brilliancy, and permanence is
desired.

Kauri. — Fossil kauri is collected by digging over fruitful areas from
which parent trees have disappeared, while fresh kauri is obtained from
the living Kauri Pine (Dammara australis}. The best fossil-kauri is
one of the most valuable constituents of good oil varnish, since it pos-
sesses the property of uniting with linseed oil more perfectly, and at
lower temperatures, than most of the resins now employed in the manu-
facture of varnish.

Shellac. — This valuable fresh-product resin is obtained from deposits
found upon twigs and small branches of certain East Indian trees (such
as Croton lacciferus). The crude exudations known as lac are believed
to have resulted from the stings of peculiar insects often found imbedded
in the twigs and branches.

The exudations, which are divided, according to form, into stick lac
and seed lac, are purified, melted, and finally spread upon flat surfaces
to cool. The resulting sheets or shells are known as "shellac." Shellac
is the principal constituent of sealing wax; and it is used for other pur-
poses, but principally in spirit varnish.

Shellac is valued in construction because, when applied with alcohol,
it is not influenced by any resins that may be within the wood. Oil
paints should not be applied directly to resinous woods; and knots should
always be coated with shellac before they are painted. Shellac varnish
is valued in this field because it dries so rapidly that resins do not have
time to mix with it. Shellac varnish is more or less influenced by water
which leaves white spots wherever it is permitted to stand long upon the
coat. Shellac is prepared by dissolving four or five pounds of shellac
in a gallon of alcohol, and should be thinned whenever necessary.

Sandarack. — This fresh product resin is obtained from trees (Callitris
quadrivalvis) which are native in Morocco and other districts along the
north African coast. There are also independent Australian and
Tasmanian sandaracks. It is a rather brittle and transparent product,
and is used to some extent in the preparation of a fairly hard, pale,
spirit varnish, suitable for light-colored woods. The resin is one of
those used in finishing pianos.

Sandarack was known to, and was used by, the ancients in their
ointments and incense. In powdered form it was once dusted over
mural decorations, to which it was later fixed by the application of
heated irons. Powdered sandarack was the English " pounce" that
was applied from pounce or poncet boxes to paper from which erasures
had been made.

Dammar. — Some of the rather soft, friable, white resins, classed under
this name are said to be obtained from the species Dammara orientalis.
As shellac is a type of the resins that serve with alcohol, so dammar is

388 ORGANIC STRUCTURAL MATERIALS

a type of those that serve with turpentine. Dammar is popular because
of the ease with which it can be dissolved. It enters the whitest varn-
ishes and is a medium in some white enameled paints. It is often hard-
ened by the addition of other substances.

Mastic. — This fresh product resin is obtained, in part at least, from
the species Pistacia lentiscus, which grows in many Mediterranean
countries. It is fairly clear and brittle, but becomes white and plastic
when masticated, hence the name mastic. It dissolves in volatile solv-
ents and serves in spirit varnishes, some of which are used to protect
oil paintings.

Rosin. — Common pine-rosin, or colophony, known as rosin, is one of
the poorest and cheapest of fresh-product resins, and is obtained by
distillation from crude turpentine. Rosin when hardened artificially
serves as a base in most cheap varnishes. Rosin varnish, when first
applied, appears brilliant and glassy, but soon fades; cracks appear,
and the varnish eventually scales from, the wood. The addition of oil
will postpone this result.

The manufacture of varnish calls for strict integrity, as well
as much skill, on the part of the manufacturer. A varnish of
cheap pine-resin can be made to resemble, in appearance, one
prepared from high-priced kauri. The proportions of oil and
other solvents, and the uses to which the mixture is to be put,
are also important. It is usually better to refer the use to which
the varnish is to be put, to the manufacturer, who, upon receiv-
ing such a statement, will submit the mixture that is most likely
to succeed.

Some Miscellaneous Materials. — Stains are dyes employed to change
the natural color of woods. They do not conceal the woods as paints
do, and differ from both paints and varnishes in that they do not form
coatings. Stains influence durability only when their constituents pos-
sess preservative properties. They are of many kinds, but may be
roughly divided as they are mixed with water or with oil. Stains are
sometimes prepared by adding a little dry pigment, such as bismark
brown, to shellac. The tints presented by most finished hardwoods
depend upon the properties of the stains that are almost invariably
used in finishing them.

Avenarius Carbolineum is an antiseptic wash or coating, the use of
which has been attended with considerable success, particularly in the
case of timbers that, after having been treated with creosote or some
other preservative, must then be cut or fitted upon the ground. The
manufacturers recommend the use of at least two coats of this pro-
prietary mixture, which is said to consist of a " coal-tar distillate" with
zinc chloride and other preservatives. It should be applied to dry and

OILS PAINTS VARNISHES AND OTHER COATINGS 389

seasoned wood. Avenarius Carbolineum stains clean wood a nut-brown
color.1

Whitewash, often used to whiten or to disinfect woodwork, is pre-
pared by digesting fresh lime in water until the lime has thoroughly
slaked; after the mixture has been strained into a clean vessel, it is
ready for use. The addition of glue, salt, linseed oil, and some other
materials, will render the coating more permanent, so that when dry,
it will not rub off on objects that come into contact with it.

Kalsomine is a mixture of fine calcium carbonate of the grade known
as Paris white, with glue, coloring matter, and water. Crude chalk,
that is, calcium carbonate, in fine powder, is agitated in water. The
coarsest particles settle first, while those that are finer remain longer in
suspension. Paris white is one of the finest of the grades thus separated.
Whiting is another grade.

Most " cold- water paint" contains small quantities of zinc oxide,
combined with larger quantities of china clay and casein. As used, the
latter substance dissolves in water but upon drying does not dissolve
a second time. " Cold-water paints," which are more or less waterproof,
are comparable with, although in many ways superior to, whitewash
and kalsomine. They are not so smooth as kalsomine and differ from
whitewash, in that they sometimes become mouldy when applied in
damp places. For this reason, they should not be used in cellars.

METHODS OF APPLICATION

METHODS USED TO APPLY PAINTS.— The methods
employed to apply paint to wood have a fundamental influence
upon the durability of the coatings. The paint should be
thoroughly mixed until it reaches an even, creamy consistency.
Portions from the top and bottom of the same pail have less
tendency to differ from one another if the paint is poured from
pail to pail, back and forth, just before using.

Exposed woodwork should be painted in dry weather, when
it is neither dusty nor very cold. It is important that the wood
should be dry. A large proportion of all failures is due to the
fact that paint is so often laid upon wood that contains some
moisture. Paint should not be applied when the weather is
foggy, nor should it be applied on frost crystals. Dry cold
weather prevents paint from spreading evenly. Dust and grease
also interfere with results in proportion to their quantities.
Painting should always begin at the top of a building and should
then progress downward.

1 Carbolineum Wood Preserving Company, New York City.

390 ORGANIC STRUCTURAL MATERIALS

Direct sunlight, particularly during the summer, is detrimental.
The heat of the sun is likely to cause the paint to form in drops
or " tears," while its reflected light will influence the vision and
judgment of the painters, who should be shifted backward and
forward, morning and afternoon, with the intention of keeping
them in the shade as much as possible.

The treatment required by new, clean wood that has never
been painted, differs from that required by a surface that has
been painted before. It is also well to distinguish between fine-
grained and non-receptive woods, and coarse-grained and recep-
tive woods. Such distinctions cause details to vary; but, in a
general way, the practice of painting may be outlined as follows:

A surface of wood that is to be painted for the first time should
be planed, sandpapered, or otherwise cleaned. The knots and
other pitch wood that may be present are next covered with
shellac; and if large knots, or other imperfections, exist, ample
squares should be drawn around them and all material within
the squares removed. The spaces left vacant should then be
filled with matched squares of good wood. It would be imprac-
ticable to attempt to fill the irregular spaces left by imperfections
with good wood.

The first or priming coat is now applied, after which all nail
holes, and other depressions, are filled with white lead putty,
which may be tinted so as to accord with the shade of the sur-
rounding surface. Ample time is allowed for the work to dry,
after which the first full coat of paint is laid on. This is succeeded
by one or more final coats as desired. It is important that every
coat should be thoroughly dry before the next one is applied.
Paint shrinks in drying and every coat should have an opportunity
to adjust itself.

Painting upon old paint is to be distinguished from painting
upon new, clean wood. Two cases present themselves: first,
the old paint, although on the whole firmly and solidly attached
to the wood, must be removed for the sake of appearance, or
because it is worn down or has failed in places; or, second, the
old paint has chalked, cracked, blistered, or become loose.

It is always better to remove old paint; yet, if the paint
adheres well, is solid, and in good condition, the cost of removing
it is not warranted, and the new coats may then be laid over the
existing work, as already noted. As distinct from this, however,
old paint that has chalked, blistered, or otherwise failed, should

OILS PAINTS VARNISHES AND OTHER COATINGS 391

invariably be removed, as it may be by scrapers, steel brushes,
burning, or by paint-removing solutions. After the old paint is
removed the cleaned surface is painted as though for the first time.

A failure occurring shortly after the application of new paint
is often attributed to some defect in that paint; whereas, in many
instances, it is the priming or old paint that is at fault. Paint
shrinks in drying, and, if the older material is not firmly anchored,
the new material is liable to pull it loose. The removal of old
paint is very costly, yet it is cheaper to remove it if it is not in a
fairly good condition.

The brush should be held at right angles to the surface so that
the extremities of the bristles will force the paint into the pores
of the wood. The strokes should be applied with the grain, and
should be drawn out as far as possible so as to reduce the breaks
in the lines of application. Paint is not distributed as evenly,
nor will it adhere as well, unless these matters are attended to.

Paint is sometimes applied in the form of spray. Thin mix-
tures, water paints, and whitewash have been successfully
applied over large surfaces in this manner. But, as distinct
from thin mixtures, the attempts that have been made to apply
thick paints by means of spray have often failed. Thick paints
seem to require a different kind of handling, and are usually
so much more costly that less waste is permissible. A machine
for spraying paint that was perfected by the Pennsylvania Rail-
road Company was once described as being " economical as a
labor-saving device as well as in saving of paint to a limited ex-
tent over brush work." This machine is still in service and giving
satisfactory results.1

It is said that spray work compares best with hand work
where there are corners or complicated surfaces. As against
this, spray sometimes encloses air which interferes with solidity
and adhesion. Experience is not sufficient to enable comparisons
to be made between these two methods.

A general specification is as follows:

Stir the paint thoroughly. Do not attempt to stir through the bung'
hole of the package, but take out the head and stir with a stick that will
reach the bottom. Finally, pour the paint backward and forward from
pail to pail.

1 July, 1915. See also general index Engineering News, 1890-1899,
p. 174.

392 ORGANIC STRUCTURAL MATERIALS

After a storm do not apply paint until the wood has had time to dry.
Never apply paint in damp, foggy, or frosty weather.

It is often advantageous to expose surfaces of smooth lumber to the
weather for a little before painting. After the side of a house has re-
ceived rain several times, the grain of the wood will rise a little; and then,
after it has become dry, the paint will adhere better.

In painting begin at the top of the building and then progress
downwards.

Knots and resinous places should be covered with shellac varnish.
After which, to wood that has not been painted before, the compara-
tively thin priming coat should be applied. The priming coat may be
prepared by adding raw linseed oil to some of the paint prepared for
the later coats.

Seams and nail holes should be puttied after the priming has been
applied. Every coat should be thoroughly dry before the coat that
follows is applied. The paint should be rubbed out well in the brush.
It should not be permitted to flow over the surface. A coat that is not
brushed out thin will blister and peel away.

Judgment is required when painting a house that has already been
painted, since different parts of such a surface may require different
treatment. Cracked and loosened paint should be scraped away. Sur-
faces that are entirely bare should be primed as already noted. Exist-
ing paint that is hard, smooth, and firm should often be roughened with
coarse sandpaper, since otherwise the new coat may not penetrate and
adhere well to it.

A specification for somewhat finer work is as follows : 1

General Conditions. Bids. — The owner reserves the right to reject
any or all bids.

No Alterations. — No interlineations, erasures or alterations of any
sort will be allowed unless duly noted and initialed by the architect.

Expert Work. — All work must be executed and completed according
to the plans and specifications, under the supervision and to the entire
satisfaction of the architect. All workmanship must be expert and
thorough in every respect.

Extra Work. — No extra work will be accepted or paid for unless or-
dered in writing by the architect before it is done.

Surfaces Before Beginning. — No wood, metal, plaster, or other work
can be painted or varnished until inspected and approved by the archi-
tect. No painting or varnishing of any kind is to be done on wet or
damp surfaces. All work must be thoroughly dry, smooth and clean,
and all scratches, bruises, cuts, pencil or finger marks or other imperfec-
tions must be obliterated before the first coat is applied. Metal sur-

1 Slightly abridged from specifications prepared by Edward Smith &
Company.

OILS PAINTS VARNISHES AND OTHER COATINGS 393

faces must be entirely free from rust, scale and oxidation as well as all
other defects.

Woodwork Before Beginning. — All woodwork must be thoroughly
seasoned, the surface must be even and thoroughly sandpapered before
the first coat is applied.

Before Beginning Work. — The painter must inspect all the surfaces
on which he is to work, before beginning, and if any of them are unsuit-
able he must immediately notify the architect. He must not begin
until the surface is in proper condition.

Sandpapering. — All sandpapering must be done with the grain and
dusted clean before applying any material over the sanded surface.

Priming Back of Woodwork. — Before bringing on the premises or im-
mediately after, the back of all fine woodwork must be thoroughly
painted.

Priming on Woodwork. — Dampness. No fine woodwork must remain
on the premises over night without receiving the first priming or filling
coat. Unless this coat is applied before delivery it must be done im-
mediately after (to prevent absorption of moisture from new plaster
or masonry, which causes warping, raising of the grain of the wood, etc.).

Second Coat Priming when Necessary. — If the first or priming coat has
been removed by accident, sandpapering or otherwise, another must be
applied to such places exactly the same as to new bare surfaces. No
succeeding coat may be applied until all such defects have been corrected
in the first or priming coat.

Puttying. — All nail holes and other depressions must be filled up level
and smooth with white lead putty, after the priming or filling coat has
been applied and is thoroughly dry. If the first coat has been removed
or broken another priming or filling coat must be applied before puttying.
All putty must be tinted with oil colors to the shade of the surrounding
surface and subject to the approval of the architect.

Puttying on Filled Woodwork. — No steel putty knife must be used on
filled woodwork. Only a hardwood stick, properly shaped, must be
used on such surfaces.

Knots and Sappy Places. — All knots, sappy, or resinous places, if they
are to be painted or enameled, must first receive one coat of the best
shellac varnish, reduced to the proper consistency, before the first or
priming coat is applied.

Each Coat to be Inspected. — Every coat must be thoroughly dry and
approved by the architect before the next is applied. No coat will be
counted or paid for without the approval of the architect.

No "Oil Rub" on Undercoats. — No oil of any kind will be allowed in
rubbing undercoats. (A portion of the oil will remain on the surface
or in the surface, no matter how carefully it is cleaned, and this is sure
to injure anything applied over it.)

Seals and Labels. — All materials to be used must be on the premises

394 ORGANIC STRUCTURAL MATERIALS

when ordered, in original packages with seals unbroken and labels at-
tached; and must be approved by the architect before they are used.

No Substitutes on Premises. Thinners. — No other materials of a simi-
lar nature will be allowed on the premises at any time. No turpentine
or other thinners may be used except as per printed directions. All
varnishes, enamels and other materials ready for use must be used
exactly as received in sealed packages from the makers.

Invoices for All Supplies. — Invoices for full quantities of all materials
needed for the work must be shown to the architect and approved by
him before the work is paid for.

Quantities Required. — At least one gallon of material must be used for
one coat on five hundred square feet of surface, except on bare wood.
First coat on bare wood, plaster or cement, etc., requires at least one
gallon of material to each three hundred square feet of surface.

Weights per Gallon. — White lead thinned down ready for use weighs
about twenty pounds to the gallon. Paste wood fillers thinned down
ready for use weigh about twelve pounds to the gallon.

Temperatures for Varnishing and Enameling. — All varnish and enamel
coats must be applied and dry dust free between 60 degrees and 80
degrees Fahrenheit. (About 70 degrees Fahrenheit is the best tempera-
ture. Fifty degrees Fahrenheit, or even lower, is not always injurious,
but the danger increases with the cold and the risk of poor results at
low temperatures should be clearly defined and the responsibility for
them placed beforehand. The danger continues until the coat is well
out of "tack.")

Materials Required. — All varnishes, enamels, japans, dryers, fillers,
stains, colors in oil, tinting colors, graining colors and similar materials
must be those manufactured by — — . All linseed oil,

white lead, white zinc and turpentine must be absolutely pure and of
the best qualities.

Danger. — Oil, lead, zinc and turpentine are exceedingly important,
and great care and vigilance are required to prevent the use of inferior
or adulterated qualities of these articles.

Covering Capacity of Paints. — Paints vary in covering capacity.
Results are influenced by the properties of the paints themselves,
by the condition of the wood to which the paints are applied, and
by the methods and personality of the painter. It is well to
allow one gallon of thin, priming paint for every two hundred
square feet of surface of open-grained wood, although it can be
made to cover twice that amount, particularly if applied to close-
grained wood. One gallon of ordinary paint should cover from
three hundred square feet to five hundred square feet of plain
surface that has already been primed. There are many excep-
tions to these general figures.

OILS PAINTS VARNISHES AND OTHER COATINGS 395

A certain amount of paint may be spread so that it will cover
a very large surface; but, in this case, the coat is likely to be too
thin. On the other hand, a coat of paint should not be too thick
because a thick coat of paint is liable to peel. As a matter of
fact, the thickest coat of paint that may be applied without
danger of peeling is actually very thin, and the saving of a small
quantity of material is less important than the length of time
during which the coat can be made to last. With charges for
labor as they are, paint should not only be selected with the idea
of obtaining the longest possible term of service, but it should be
applied with that object first in view.

Time Required to Apply Paint. — The time required to apply
paint is influenced by the paint itself, the surface that is to be
covered, and the habits of the painter. An intricate surface
requires longer than one that is plain and flat. It takes longer
to apply paint overhead than to apply it on a level with the body;
and it is easier to work from a scaffold than from a ladder.
Fine interiors call for more attention than ordinary exteriors.

Inquiries addressed to several railway companies brought replies indi-
cating that a good workman should cover from fourteen hundred square
feet to two thousand square feet of plain, flat, primed surface in a day
of eight hours. Priming requires longer. At least ten per cent, of the
time devoted to painting should be allowed for cleaning, sandpapering,
puttying, and mixing. These figures, although based upon actual work,
cannot be applied too literally, particularly to small pieces of work, or
when fine surfaces are to be prepared.

Durability of Paints. — This varies greatly with materials,
methods of application, use, and exposure. The need of judgment
and integrity on the part of the painter is very great. Sunlight
and rain are the common enemies of paint. White lead will last a
century under cover, but fail in a few years when out of doors.
Impure air, and moist gases such as come from locomotives,
destroy paints more or less rapidly. The life of a coat of paint
cannot be predicted, even when it has received the most intelli-
gent attention. When the coat fails it must be renewed.

THE APPLICATION OF VARNISH.— Varnish may be used
as paint is used, or it may serve in connection with the more
complicated surfacing included within the meaning of the word
polish. Although varnish is used in polishing wood, a varnished
surface is to be distinguished from a polished surface.

396 ORGANIC STRUCTURAL MATERIALS

Many of the details connected with wood finishing in which
varnishes are employed are specially associated with certain kinds
of work. The protection of a porch or mast differs from the re-
quirements of a piano or a coach. Appearance is of much im-
portance with most woodwork upon which varnish is employed.

The appearance of cabinet woods is influenced by fashion, and
fashion changes so that the same wood is often finished in differ-
ent ways at different times, even although the wood is to be em-
ployed for the same purpose. Mahogany may 'thus be finished
with a bright luster; or it may be dull. Sometimes it is of a rich
mahogany red, and at others it is yellow or dark brown. Oak
is finished in many colors such as natural yellows, grays, greens,
browns, and blacks. These results are obtained by the use of
stains, varnishes, wax, and other materials, and by differences in
methods of application.

The principal difference between a plain varnished surface
and one that is polished is due to a distinction between the
amounts and kinds of labor that are employed.

It will be remembered that woods are divided according as
they are porous, like mahogany, or close grained, like maple.
All woods must be dry, and all must be brought to a smooth,
clean, even finish before they are treated in any way.

Plain Varnished Surfaces. — Varnish may be used as paint is
used. It may be applied directly to filled or unfilled woods.
The varnish need not be rubbed down and polished.

Filler may be used upon a surface that is to be varnished.
The procedure resembles that associated with the preparation of
surfaces for polishing, but is distinct in that, as stated, the var-
nish is not rubbed down and polished after it has been applied.

Varnish is often applied to otherwise unfilled wood, in which
case the varnish itself acts as a filler.1 The very durable and

1 From correspondence with William H. Oliver: "In years past many of
the wood polishers made their own filler, but it was even then thought that
the better way to treat hard woods was to give them all the oil or varnish
they would take. Each coat was sandpapered to the surface of the wood,
and it was necessary to repeat the coats and the sand papering until the
pores were thoroughly filled. Afterward, the necessary coats to preserve
the wood and permit polishing and rubbing were added. I have always
been of the opinion that if this course was generally followed at the present
time better results would be obtained. I hold that in this way not only
are pores filled, but the wood is better protected. It seems to me that
wood thus treated is brighter and clearer than when ordinary paste filler

OILS PAINTS VARNISHES AND OTHER COATINGS 397

elastic mixture known as spar varnish is often used in this way
upon masts, doors, porches and other exposed woodwork.
When thus used, applications of this varnish are repeated until a
sufficient body has been built upon the wood. A coat prepared
in this way will not separate from the wood even when exposed
to the most severe weather1.

Polished Surfaces. — Although the engineer has less to do with
polishing than with painting, the subject deserves attention suffi-
cient to enable him to specify such fundamental factors as are
necessary to secure the results he desires.

Close-grained woods are first treated with appropriate fillers.
The unabsorbed portions of the fillers are rubbed away with rags
or excelsior as soon as they have had time to dry, the movement
being across the grain. The cracks and nail holes are next
puttied; the surface is sandpapered, andj if a stain is desired, it
is applied at this stage. Afterward, a thin coat of light-tinted
or orange shellac is brushed on and the surface is again sand-
papered. A coat of varnish is spread evenly over the surface,
and is allowed to dry for two or three days. The surface is
then attacked by powdered pumice, with oil or water, and rubbed
with the grain, until, to all appearances, it is removed. Felt or
haircloth is used in this operation.

Other coats of varnish are added in the same manner. Each
one is allowed to dry thoroughly, and is then rubbed down to a
smooth surface with powdered pumice. The polish is brought
out by rubbing the last coat with rotten-stone instead of with
pumice.

Details vary with fashions, finishers, and the necessities of the
wood. Very smooth surfaces, such as those seen on pianos, are
obtained by finally rubbing the surface with the palm of the
hand. Oil and pumice give what is known as " oil-finish,"
while water and pumice give what is known as " water-finish."
The appearance and wearing qualities of polished surfaces vary
greatly. Some surfaces appear to be thick and glassy, while
others are more solid, and subdued.

is employed, and that it is better, also, for the life of the wood than a
material is which simply coats the surface, but has no real penetrating
power. ... I have thought for some time that the filler generally used
not only darkens light wood in time, but that it has some chemical action
upon the varnish or shellac ; but whether this is so I must leave for others
to determine."

1 See "Technology of Paint and Varnish," Sabin (First Edition, p. 299).

398 ORGANIC STRUCTURAL MATERIALS

In the best work, the varnish penetrates deep into the wood.
Such a surface is " case-hardened;" it wears evenly because the
wood elements of the surface are filled and rendered compact by
the tough hard varnish. In this case very little varnish remains
on the outside of the wood, and, with ordinary use, the appear-
ance of such a surface may improve with age. Where the work
is inferior very little labor is bestowed upon the varnish. The
superfluous varnish is not rubbed away, and no attempt is made
to work the first coats into the fabric of the wood. In this case
most of the varnish remains upon the surface of the wood;
such a surface may be more or less attractive when new, but
shortly scratches, chips and wears away.

As already stated, the appearance of a surface is influenced
by its color as well as by its texture. The tints presented by
most finished hardwoods are secured by the use of stains, and,
in the best work, these stains are selected so as to accord with
and emphasize such beauty as is due to the cellular structure or
" grain" of the wood.

It is fundamental that stains shall be spread evenly. This is
often hard to accomplish because different parts of a piece of
wood are liable to vary in their density and ability to absorb.
It is often necessary to retouch the wood here and there so as
to offset such differences. Many stains darken with age, and it
is usually easier to correct a tint that is too light than to correct
one that is too dark.

The summary that follows was prepared by the foreman of a
noted firm of cabinet makers.

"In order to secure a good piece of work: (1) Fill with the best
filler; (2) color if necessary; (3) apply a thin coat of the best shellac;
(4) apply three coats of the best varnish — allow each coat to dry for
two days at least; (5) rub down each coat until a smooth surface is ob-
tained with pumice stone and felt — allow one day to dry perfectly, then
finish with rotten-stone, and, if a very fine surface is required, rub with
the palm of the hand; (6) clean entire surface of work with a mixture
of raw linseed oil and turpentine (equal parts), then take cheesecloth
and rub perfectly dry. To obtain the best of work, it is absolutely
necessary that the woodwork be perfectly smooth and well filled before
the work is varnished."

Enameled Surfaces. — Varnish or enamel paint has been de-
scribed as a mixture of varnish and pigment. In such a paint,
.varnish takes the place of the usual linseed oil, with the result

OILS PAINTS VARNISHES AND OTHER COATINGS 399

that the paint, although more costly, is harder and more durable.
A little varnish is often added to ordinary oil paint, the luster of
which is thus increased. Enamel paint may be applied on wood
or metal either indoors or out of doors. The paint may be laid
on as described in the preparation of " plain varnished sur-
faces;" or, a real enamel may be built up by methods described
in connection with " polished surfaces."

In the latter case, the wood, having been prepared and primed in the
ordinary manner, is treated to two or three coats of flat white lead paint
each one of which is permitted to dry thoroughly, and is then lightly
sandpapered. One coat of zinc white paint is then applied, and, after
it has become dry, is also sandpapered. The base thus prepared is
covered with a coat of enamel paint which is later rubbed down with
pumice stone and water, on felt, to a uniform and level surface. This is
carefully washed free of all pumice with cold water, and is then wiped
dry with chamois. One or two other coats of enamel paint are then
applied in the same way. A surface built up in this manner is very
beautiful, smooth, easily cleaned, neutral, and permanent. A base of
birch or cherry thus enameled is usually more costly than a base of
quartered oak or even mahogany that has been polished. The differ-
ence in cost is due to the excessive amount of labor required to build
up good enamel.

Varnish is sometimes replaced by wax which causes an old,
or " antique" appearance. The wood is first leveled, sand-
papered, cleansed, or otherwise prepared; and is then stained and
treated with shellac, varnish, or with both of these mixtures.
Wax is applied and time is allowed for it to dry. The whole
surface is then carefully rubbed with cheesecloth or some similar
material. The shellac and varnish are sometimes omitted.
Appearance is governed by these and other details.

MISCELLANEOUS. — Ships, cars, coaches and some other
constructions, require special methods that are distinct from
those by which ordinary woods are commonly protected.

Ship Painting. — Ordinary wooden hulls are protected much as
wooden houses are protected. But, as distinct from these, many
pleasure boats and war ships require special treatment. The
vessels now referred to are those that are painted so frequently
that excessively thick coats of paint would accumulate if ordinary
methods were held to. In such cases, white lead is mixed with
turpentine instead of with linseed oil. This produces a thin
white coat that looks well for the time being, but that soon

400 ORGANIC STRUCTURAL MATERIALS

chalks, and can then be brushed away. Special paints have been
designed to protect ship bottoms.

Coach Painting. — In this case, brilliant polishes have to resist
severe exposure and constant washings. The influence of heat,
cold, wet, and abrasion must be withstood. Coach painting
occupies a field by itself.

Car Painting. — Methods employed in the shops of the Pullman
Company are as follows:1
System for Painting Exteriors of Cars.

1. After the exterior of the car has been properly sanded and made
ready for painting, dust off the car with a painter's duster, and then
apply the priming coat, which should be well brushed into wood and
allowed to dry three days.

2. Apply the filling coat, or the second lead.

3. Putty all nail holes and bruises the next day, and then allow the
second lead and putty to dry two days.

4. Apply three coats of surfacer, one coat a day.

6. Rub down to a smooth surface with lump pumice stone or Eureka
rubbing stone, and then sandpaper.

6. Apply the color course of two or three coats, one a day.

7. Ornament and letter and then apply three coats of Railway Body
Varnish, allowing a day between coats for drying.

System for Finishing Interiors of Cars.

1. After the finish is properly cleaned and sandpapered, fill the pores
with a wood filler and allow it to dry over night.

2. Sandpaper with No. 0 sandpaper; shellac and varnish it the next
day and allow it to dry one day.

3. Apply the second coat of varnish and let dry one day.

4. Apply the third coat of varnish, letting it stand to dry two days
before rubbing.

5. Rub with pumice stone and water and let dry one day before
polishing.

6. Polish with rotten stone and oil.

OTHER COATINGS APPLIED TO SURFACES OF WOOD.

— Metals are sometimes used to beautify woods and to protect
them from decay; but they, as well as paints, seal up moisture
that may be present, and should not be used save with woods
that are quite dry and well seasoned. Wooden pillars are some-
times enclosed by metals, as are the bottoms of wooden ships.

The bottoms of posts and poles are sometimes charred. As
has been explained elsewhere, high heat sterilizes the wood and

1 In force January, 1912.

OILS PAINTS VARNISHES AND OTHER COATINGS 401

thus increases its durability; but, besides this, the coat of prac-
tically inert charcoal is also beneficial.1 Charring can be local-
ized, and is often practised with the ends of green posts that would
otherwise rot rapidly near the surface of the soil. The upper
portion of such pieces then have time to season naturally.

FIG. 79. — Failure of car post due to application of paint upon imperfectly

seasoned wood.

Attention has been called to the fact that external coatings
may assist wood by offering resistance to animal woodborers,
fire, an abrasion, as well as to rot. Asbestos paint, in which
water-glass is the vehicle and powdered asbestos the pigment,
is thus used as a fire retardant. The water-glass fuses easily,

^ee chapter, "Preservative Methods Internal Treatment."

402 ORGANIC STRUCTURAL MATERIALS

and, when fused, flows over the burning surface, and for the
time cuts off the volatile gases that cause flame.1

It will be remembered that so-called " fireproof paints"
retard, but they do not prevent, burning. Some paints of this
class act upon woods when in certain positions by lessening the
ease with which such woods might take fire from small flames.
It will also be remembered that wood covered with tin has re-
sisted fire in conflagrations when solid metal has buckled and
failed.

THE PREPARATION OF WOODS TO RECEIVE PAINTS, VAR-
NISHES AND OTHER COATINGS

Coatings protect from outside conditions only. They do not
protect from inside conditions, and may even do harm if mois-
ture or impurities are not removed before they are applied.
It is then much the same as when imperfectly cured fruits are
sealed in cans. Decay can go forward within a can, and it
can also go forward within a coat of paint. The condition
known as " dry-rot" is observed where imperfectly cured woods
are thus enclosed by paints or other coatings.

1 See chapter, "Failure of Wood Because of Fire."

CHAPTER XVI

ADHESIVES. CATTLE GLUES. FISH GLUES. SELECTION,
TESTING AND APPLICATION OF GLUES

Glue is prepared from parts of animals. It is used to join
pieces of wood together; and is also used in printers' rollers, emery
wheels, book bindings, artificial leather, and for sizing cloths
and papers. Kalsomine is a mixture of glue and Paris white.
About ninety million pounds of glue are produced in the United
States alone every year.

True glue is impure gelatine. Gelatinous pastes resembling
jellies of weak glue, are formed by some vegetable products; but
these pastes differ from true glues in that they do not resume
their original forms when they become dry, neither do the dried
products dissolve satisfactorily the second time. A jelly of true
glue will dry into a substance that is practically identical with
the original, and this substance will dissolve and then gelatinize
a second time.

Glues and gelatines should be distinguished from one another.
Both substances are obtained from the same sources, but the
former is less definite in composition than the latter. Pure
gelatine may be described as the essential part of glue, while
glue may be described as impure gelatine. Ordinary carpenter's
glue contains about fifty per cent, of pure gelatine which may
be separated from the glue by laboratory treatment. As a
matter of fact, commercial gelatine or isinglass, as distinct from
pure gelatine, is usually prepared directly from special sources.
The line of separation between some glues and some gelatines
is hard to define.

REFERENCES. — "Glue, Gelatine, Isinglass, Cements, and Pastes," Dawid-
owsky (Sampson Low, Marston, Searle & Rivington, London, 1884); "Glue
and Glue Testing," Rideal (Scott, Greenwood & Company, London, 1900);
''Glues and Gelatine," Fernbach (Van Nostrand Company, 1907); Files of
Scientific American, Woodcraft, etc. Assistance has also been received from
Messrs. Armour & Company, the American Glue Company, the Russia
Cement Company, the Studebaker Corporation, Schmitt Brothers, The
Flint & Horner Company, and other manufacturers and users of glue.

403

404 ORGANIC STRUCTURAL MATERIALS

Gelatine, which is nearly colorless, nearly tasteless, and almost
without odor, is used in medicines, photography, confections,
and as an agent in clarifying liquids. As distinct from gelatine,
glue possesses color, taste, and odor; but, because glue is used
primarily as an adhesive, these properties do not diminish its
value.

The exact chemical composition of pure gelatine has not yet been
deduced, but analyses show that the ultimate composition is about as
follows: Carbon, 50 per cent.; oxygen, 25 per cent.; nitrogen, 18 per
cent.; hydrogen, 6.9 per cent.; sulphur, etc., traces. Rideal and Fern-
bach1 call attention to the complex composition of gelatine. Beside
albumoses and peptones, several varieties of chondrin, mucin, and other
chemical substances may be present.

Glues and gelatines are derived from cattle and from fishes.
Cattle glues are more largely used, and are usually intended
unless fish glues are particularly specified. It should be noted
that glues and gelatines do not exist as such in the tissues from
which they are drawn, but that they are formed by the action
of heat and water upon certain nitrogenous substances that are
contained in, or that are a part of, these tissues. The fact that
certain animal tissues can be made to yield certain products
through the instrumentality of heat and water is known, but
the nature of the changes which brings about these results is
not known.

CATTLE GLUES

SOURCES. — The sources of cattle glue may be separated into
three groups as follows:

Hidestock includes scraps and cuttings from tanneries, to-
gether with sinews, and pieces known as fleshings that are
shaved from inner surfaces of skins. Hidestocks from horned
cattle, sheep, rabbits, and other animals, yield glues that differ
from one another in minor properties. The second group in-
cludes bonestock, that is, the bones of certain animals as horned
cattle; and footstock includes the hoofs of horned cattle, pigs,
and some other animals.

MANUFACTURE.— Clean hidestock is digested or "limed"
in some weak alkali, as lime water, that attacks the fats, loosens
the hair, and softens the tissues that contain the glue. After

1 See text by these authors.

CATTLE AND FISH GLUES 405

a sufficient time the alkali and impurities are removed by wash-
ing, and the soft and swollen residues are boiled in water. Each
charge of stock is boiled several times, but the solutions are kept
separate from one another since each one yields a different grade
of glue. The best glue is that which comes from the first boiling.
Next, the glue solutions are poured into moulds and per-
mitted to cool, and the blocks of jelly that result are cut into
slices. The slices are arranged on nets of twine or wire designed
to facilitate drying, and are dried in the open, or in cabinets
where conditions may be more easily controlled. It is not easy
to dry these jellies satisfactorily. Results are much influenced
by temperature and humidity. Some difficulties are expressed
in the following quotation:1 "The glue-maker has all sorts of
troubles. His best jelly may be hurt or ruined by the weather
or by unwise liming or cooking. Anything will affect his glue
and, for this reason, no two boilings can be alike."

Bonestock. — Clean bones are treated in either of two ways: First,
They are boiled directly without prior treatment; or second, they are
digested in weak acids that dissolve the lime and other salts. The acids
are then neutralized and the cleansed residues are boiled in water. The
solutions obtained from the bones of different species of animals yield
different grades of glue.

Footstock. — This is washed and boiled without preliminary treatment.
The solutions obtained by boiling the hoofs of different kinds of animals
are kept separate from one another.

PROPERTIES. — Cattle glues are hard and tough. The taste
and odor are characteristic, and the colors range through a series
of more or less translucent grays and browns. Cattle glues
soften and swell, but do not dissolve, when treated with cold water.
They dissolve completely in hot water, and the resulting solutions
eventually stiffen into jellies and pass into the original dry form
of the glue. Cattle glue can be dissolved and dried many times;
but each operation weakens the power of the glue, and a point
is finally reached where the glue remains permanently in solution.
Cattle glue also dissolves in acetic acid.

Many grades of glue are manufactured in the United States.
Some are based upon differences that exist between the materials
from which the glues are made; and others are due to differences
of manufacture. Every maker produces a series peculiar to him-
self, and the properties of the grades that go to make up this

1 "A Pot of Glue," Milligan and Higgins Company.

406

ORGANIC STRUCTURAL MATERIALS

series sometimes change from day to day with the weather, or
from other causes.

Glues differ in form as well as in character. Foreign glues are
usually sold in square or oblong cakes, each of which is branded
with the mark of the manufacturer. As distinct from this,
glues made in the United States are usually broken into frag-

FIG. 80. — Typical forms of domestic and foreign cattle glues. (Much
reduced.) The cakes of foreign glue at the top of the picture show the
brands of manufacturers.

ments, known as " flakes," and these are often ground into powder.
There are also noodle, strip, ribbon, and some other forms.

Two reasons are given for the local custom of breaking the cakes of
glue into fragments: The first is, that inequalities can be counteracted
by judicious blending; and the second is, that it is easier for consumers
to work with glues that have been broken for them. The viewpoint of
the manufacturer has been expressed as follows:1 "The boilings of glue

1<4A Pot of Glue," Milligan and Higgins Company.

CATTLE AND FISH GLUES 407

run from three to ten barrels, and, as said above, vary. But take ten
boilings, say fifty barrels, and grind them together we can then give a
man a sample behind which we can be sure of every pound; and we can
make successive lots to match that one. It means uniformity, conven-
ience, and economy." It is true that cattle glues must be broken be-
fore they are dissolved in water, but the convenience of having them
broken by the manufacturer is sometimes offset by the greater ease with
which fragments or powders can be mixed or even adulterated by un-
scrupulous dealers.

Comparison of Foreign and Domestic Glues. — Foreign manu-
facturers seldom employ as many kinds of stock, or produce as
many grades of glue, as those who manufacture in this country.
The foreign custom of presenting glues in unbroken or branded
cakes makes it easier for consumers to identify foreign glues.
Foreign makers give much attention to appearance; labor condi-
tions are such that stock can be selected with greater care than
in this country, and glue solutions are often clarified to such an
extent that foreign glues are nearly, if not quite, translucent.

Aside from form and appearance, it is probable that the domes-
tic product as a whole, is quite equal to the foreign product
as a whole. It is true that the large number of grades of glue
manufactured in the United States causes some confusion, since
customers, who are often unable to tell one kind from another,
must depend more largely upon those from whom they buy.
But, on the other hand, the fact that there are so many kinds of
glue is a source of strength, because it makes it possible for
Americans to fill almost every need.

Special Forms. — Cattle glue is sometimes dissolved in acetic
acid and then sold in the form of a liquid. Cattle glue may be
rendered flexible by mixing it with glycerine and water, to which
molasses, or sugar in some other form, is usually added. The
proportions of ingredients vary according to the results desired;
a mixture composed of one-half glycerine and one-half glue is
fairly rigid. Flexible glue compounds are used in book bindings,
printers' rolls, and for other purposes.

Failure of Glue. — Heat and moisture are common enemies of
glue. All glues soften, more or less, under the influence of water;
but some kinds offer more resistance than others. The grades
that last longest when exposed to moisture are sometimes re-
ferred to as "waterproof glues," but should not be confused with
special mixtures that are also known as " waterproof " or "marine

408 ORGANIC STRUCTURAL MATERIALS

glues." Resistance to moisture may be increased artificially by
the application of formalin. The other common enemy referred
to, that is, dry heat, causes some glues to shrink and become
brittle.

Selection. — Glue may be perfectly good, yet may be unsuitable
for the work in which it is employed. In the glues that are used
in carpentry, it is important that adhesive powers should be
highly developed; whereas in some other glues, that are valued
for other purposes, other properties are at least equally important.

Taken all in all, the best glues with woods are those made from
hidestock, although glues made from footstock are also prized
in joinery, because the sinews that adhere to the hoofs yield
material that possesses high adhesive value. Glues made from
acid-treated bones appear well, but sometimes crack when used
under conditions that exist in the United States, and, for this
reason, are often less desirable in joinery than are some others.

All glues look much alike to casual observers. Those who use
large quantities of this material learn by experience the kinds
best fitted for their needs; but those who use glue only occa-
sionally should refer their problems to reliable manufacturers,
who will suggest the grades that are best fitted to meet their
requirements.

APPLICATION.— The strength and durability of a joint are
influenced by the way in which the glue is applied. The glue may
be good and appropriate, but the joint will fail unless the glue
is applied in the proper manner. Several details are important:
(1) the glue must be carefully dissolved; (2) the wood must be
ready to receive the dissolved glue; and (3) the wood and glue
must be brought together in a way that has been shown by
experience to produce lasting results.

1. Dissolving the Glue. — There are two parts to this process.
First, the glue must be softened, and for this purpose, it is placed
in from two to four times its weight of cold water. Broken
glues must remain in the water for several hours, but ground
glues often soften sufficiently in five or ten minutes. Second,
after the removal of the excess water, the soft arid swollen mass
must be warmed until it is thoroughly dissolved. Care must be
taken to avoid direct or high heat. Many devices are available
to protect glue from excessive heat during this part of the process.

2. Preparing the Wood. — The wood should be clean, well-
seasoned, and sufficiently warm. The surfaces of close-grained

CATTLE AND FISH GLUES 409

woods should be roughened, and the same treatment should be
extended to other woods when necessary. The film that forms
over the surface of melted glue when the warm solution is chilled
by contact with the air is duplicated when the solution is applied
to the normally cooler surfaces of woods. For this reason, cabi-
net makers warm pieces of wood that are to be joined by glue.
Care is necessary here also, since high heat is injurious to wood
as well as to glue.

3. Completing the Joint. — Penetration, warmth, and pressure
are necessary. The glue must sink into the "take hold" of the
wood. To bring about this penetration, the differences in pene-
trability of close-grained and hard-grained woods, must be kept
in mind. The necessity for warmth has already been explained.
Pressure is very necessary because some time must elapse before
the glue can set sufficiently to hold the parts together; the parts
are therefore held in presses during this interval. The object
throughout is to bring the pieces together in such a way that the
joint will be at least as strong as the wood.

A series of axioms relating to the application of cattle glues
given by Fernbach is as follows:1

"When two surfaces of split wood are laid together, the hold of the
glue is the same whether the fibers are laid parallel or crosswise to one
another.

"The value of a wood joint is dependent upon the union of the glue
with the fiber of the wood. For glue to be properly effective, it must
penetrate the pores of the wood; and the greater this penetration, the
more substantial the joint.

"All other factors being equal, glues that dry slowly are invariably
stronger in the joint than those that dry rapidly.

"Except in the case of veneering, both surfaces of the wood should be
properly glued before junction.

"Do not use thick solutions of glue for joint-work. They congeal
too quickly, and hence fail to penetrate the pores of the wood, yielding,
as a result, a weak joint. In every case, the glue must be worked well
into the wood with a brush, much in the same manner as a coat of paint
is applied.

"If glue is applied to hot, as distinct from warm, wood, all the
water of the glue solution would be absorbed by the wood, leaving
a thin inadhesive coating of glue at the surfaces of the joint, which,
if made in this fashion, will hold only a limited time."

1 "Glues and Gelatine" (1907 Edition, p. 106).

410 ORGANIC STRUCTURAL MATERIALS

The action of glue in a joint is thus described by Hewitt:1

"Glue forms a true solution with water at temperatures above one
hundred and forty degrees Fahrenheit. It passes out of solution gradu-
ally as it cools below this point. The molecules of glue then join with
one another and the water that is excluded occupies the vacant places
in the resulting tissue.

"Glue should be in solution as it passes into the pores of the pieces
that are to be joined. To insure this the temperature of the pieces
should be raised to a point somewhat in excess of one hundred and forty
degrees. The glue and water will then pass in together and a strong
net work is formed as the glue separates from the water.

"Ordinary carpenter's glue contains from forty per cent, to fifty per
cent, of pure gelatine. The balance is glue peptones, caused by gelatine
breaking down at various stages. The true gelatine will not adhere if
the glue is applied at temperatures below one hundred and forty degrees
Fahrenheit. Some adhesion is caused by the peptone substances but
the joint is not as strong as it should be. The matter is complex but
the principle is that the glue or gelatine should be applied when suffi-
ciently hot and concentrated."

PROTECTION OF JOINTS.— Since heat and moisture are the
common enemies of glue, all joints in which glue is used should be
protected from these known elements of failure as far as this is
possible.

Protection from Heat. — Some glues resist the influence of dry
heat better than other glues. It is probable that the best results,
when this material is used with wood, are obtained by the use of
selected glues made from hides. Bone glues are less stable,
more likely to shrink and become brittle under the influence of
dry heat.

Aside from the glue, the wood itself requires attention. It
is necessary that the pieces to be joined should be dry and well-
seasoned. Some failures of glued joints can be traced to the
shrinking and warping of the woods themselves.

Protection from Moisture. — Resistance to moisture may be
increased by the use of selected glues. . Formalin, if used in this
connection, should be applied after the joint has become dry.
The glue may swell a little, but the antiseptic renders it compara-
tively insoluble, and glue treated in this way, never decays under
ordinary conditions. After the work has become dry, it should
be protected by paint or varnish.

1 Correspondence quoted by permission.

CATTLE AND FISH GLUES 411

Joints can be protected so that they will resist seemingly adverse
conditions for a long time. This is shown by boats manufactured by
the Racine Boat Company. The hulls of these boats were built of
layers of thin veneer glued crosswise upon one another, and it is said
that they remained sound as long as they were protected by paints or
varnishes. " The actual use of the boats demonstrated that they require
considerable care. They could not be left in the water or sun indefi-
nitely. The strong rays of the sun on the boats in the water would
blister the veneer and the blisters would naturally form checks. This
was overcome by putting on little copper patches. Boats that had good
care have stood for twenty-five years. There are still some in existence
and the owners write that they would not sell them for any cost."1

DURABILITY OF JOINTS.— The durability of a joint must be
distinguished from the durability of the glue used in the joint. The
glue itself may be good and appropriate, but the joint will fail if
the glue has not been well applied, or if the joint has not been
properly protected. Glue can be selected, applied, and protected
in such a way that the work will last indefinitely.

FISH GLUES

SOURCES.— The dry forms known as isinglass are prepared
from the swimming bladders of certain fishes. Dry fish glue or
isinglass is seldom used in carpentry and is mentioned in this
place only for the sake of completeness. Ordinary or liquid
fish glues can be, but seldom are, prepared from isinglass.
These forms are normally extracted from the heads, skins, and
bones of cod, cusk, and other fishes.

The best isinglass is made from sturgeon in Russia. American isin-
glass is prepared from the swimming bladders of cod and hake; there
are other sources in other countries. Isinglass is nearly colorless, and
nearly tasteless, and is used chiefly in medicines, confections, and as an
agent for clarifying liquids (see also " gelatine"). As cattle glues are
normally solids, so fish glues are normally liquids. Much, if not most,
of the liquid glue manufactured in the United States is drawn from the
skins, bones, and other waste now separated from the flesh of cod before
the latter is marketed. Many thousands of tons of this stock are pro-
duced on the New England coast alone every year.

MANUFACTURE. — Some liquid fish glues are prepared by
boiling the sounds of cod and hake in water. But by far the
larger part is prepared as follows: The heads, skins, and bones

1 Correspondence with Racine Boat Manufacturing Company quoted by
permission.

412

ORGANIC STRUCTURAL MATERIALS

containing the glue are freed from salt and dirt and are then
subjected to processes of extraction that resemble those em-
ployed in the preparation of cattle glues. Preservatives are

FIG. 81. — Fish sounds, Nova Scotia.

added, and the characteristic fish odor is disguised by adding
essences. The results are not dried, but are marketed in liquid
form.

CATTLE AND FISH GLUES

413

PROPERTIES. — Fish glues are powerful adhesives, but they
do not always sink easily into close-grained woods. The liquid
form is convenient because it makes it possible to use the glue
without further preparation. Fish glue is thick and often be-
comes thicker when cold; and, at such a time, it must often
be warmed before it can be poured from the can or barrel in
which it is stored. Small quantities of glue are easily thinned
by the addition of water, vinegar, or acetic acid, or by warmth.

FIG. 82. — Typical fish glue.

Fish glues are particularly convenient with small or occasional
pieces of work that must be undertaken where facilities for
preparing joints of cattle glue do not exist. Their use with woods
is limited because cattle glues are cheaper, and, in the majority
of cases, sufficiently good. Large quantities of fish glues are
employed for gumming labels, stay-papers, etc.

Selection. — Classification is based primarily upon the source of
the glue, and secondarily, upon the body and color of the glue.
The better grades, which alone should be used with woods, are
made from the skins of cod and cusk, while less desirable grades
are made from the heads, bones, fins and tails of the same fishes.

414 ORGANIC STRUCTURAL MATERIALS

Fish glues are presented under labels and can, therefore, be readily
selected by customers. Special problems should be submitted to
manufacturers.

APPLICATION. — Fish glues do not have to be dissolved, and
pieces of wood to be joined by them do not have to be heated.
Aside from this, the application of these glues resembles that of
cattle glues. In both cases, the glue should be made to penetrate
as far as possible, and in both cases, the pieces to be joined should
be held in place firmly until the joint has had time to set. Some
directions prepared by the Russia Cement Company of Glouces-
ter, Massachusetts, relating to the application of fish glues, are
as follows:1

"The joint should first be made to fit as accurately as possible. A
thin coating of glue is allowed to set which will take only a few minutes.
While the glue is still tacky, another coating of glue should be used, and
the joints rubbed together, plenty of time being taken to force out all the
air, so that there will be no air bubbles, and so that the entire surface
to be glued will be covered with a thin film of glue. Pressure should
be used so that only a small amount of glue is left, as too much glue is
injurious as well as too little. Pressure should be kept up until the glue
is quite dry. If the above directions are followed, any piece of wood
should give before the glue.

"There is a certain knack even in following the above directions, and
the only way to obtain good work on animal as well as fish glue is by
experience in the use of particular glues for particular woods, and this
can only be acquired by time. There is no absolute rule which can be
followed."

SOME USES OF GLUE

With woods, glues are used to wholly or partly replace nails;
and they are also used in veneered or "built-up" work, such as is
called for in cabinet making, parquet floors, and the bodies of
fine carriages. The latter field is so important as to warrant
notice. The fact that glues are used for other purposes than to
join woods has already been noted.

VENEERS. — This term is applied to thin slices of wood that
are later fastened to, or reinforced by, other pieces of wood.
Veneers are cut with knives, or with saws. The first method,
which is often preferred with more valuable woods, is compara-
tively economical as to material, while the latter method is

1 Correspondence quoted by permission.

CATTLE AND FISH GLUES

415

easier as to labor but causes much of the log to be lost in sawdust.
Rotary-cut veneers are broad ribbons pared from the surfaces of
revolving logs. There are also plain-cut and quarter-cut veneers
which are prepared as is indicated by their names.

Veneers ordinarily vary in thickness between one-thirtieth of an inch
and one-quarter of an inch. Veneers as thin as one tw(5-hundredth of

FIG. 83. — Large double-cylinder veneer press.1

an inch can be prepared, but the value of such sheets is lessened by the
fact that the glues used to fasten them are liable to soak through and
become evident on the outer surfaces. Most inside needs are met by
thicknesses between one-thirtieth of an inch and one-eighth of an inch.
Veneers that are to be exposed to the weather should be thicker than
one-eighth of an inch. Veneers that are one-quarter of an inch or more
in thickness are usually classified as thin lumber.

1 Photograph courtesy Hydraulic Press Manufacturing Company.

416

ORGANIC STRUCTURAL MATERIALS

Preparation of Veneered Work. — The form to be covered is
prepared of white pine, or some other clean, and uniformly
grained wood that receives glue in a satisfactory manner.
__ _ , This foundation is termed the "core."

Another piece, called the "caul,"
the surface of which coincides with
that of the core, is then made ready.
The pieces of veneer are fitted over
the surface of the core, glued in
place, and held there intimately by
means of the caul. The entire
series, composed of core, glue,
veneer, and caul, is then placed in a
press where it remains until the glue
is dry. Curved, irregular, and in-
tricate surfaces are correspondingly
harder to prepare than plain surfaces.
Door frames are made by gluing
strips of wood to one another and
covering them with thick veneers,
or "thin lumber." Chair seats are
prepared by gluing layers of wood,
of equal thickness, crosswise to one
another. The names three-ply or
five-ply are used where three or five
thicknesses of wood are thus fastened
together. The roofs of many car-
riages are made by covering three-
ply roofing with heavy duck, slushed
on and tacked at the edges. The
use of veneers in building hulls of
small boats has been alluded to.

Inlaid Work. — This is prepared by
fastening a sheet of light-colored

sheet of darker wood, such as

mahogany. A design is traced upon the upper sheet, and a
sharp knife is passed over the design so as to cut through both
sheets alike. The figures cut from the lighter-tinted wood are
inserted within the corresponding vacant spaces in the darker
wood, or vice versa, and the sheet with insertions is glued upon a

PLATE XX. APPLICATION OF GLUE IN LARGE CURVED JOINT

CATTLE AND FISH GLUES 417

core of seasoned wood. There are many details and applica-
tions.

Reasons for Preferring Veneered Work. — Some reasons for
preferring veneered work are as follows:

Stability. — The natural tendency to warp and check is less
when well-seasoned pieces of wood are glued crosswise to one
another. Results obtained in this way are stronger, better, more
rigid, and lighter in weight, than when solid wood is employed.

Appearance. — The best and most beautifully figured pieces of
wood are often small. Such perfect, attractive, but small pieces
can be sliced, and the slices joined together so accurately, over a
core of some less desirable wood, that the seams cannot easily be

FIG. 85. — Portion of three-ply panel.

discovered. A large surface of perfect and uniformly beautiful
wood is thus obtained.

Economy. — As a matter of fact, veneered work is usually more
costly than solid work of equal dimensions. It is cheaper than
solid work only when the saving of material is enough to more
than offset the extra expenditure for labor. From the viewpoint
of material, the case is the same as when one metal is plated with
another; but from the viewpoint of labor, the cost of preparing,
fitting, and gluing thin sheets of wood over a curved or irregular
surface, or even one that is flat, is greater than the cost of pre-
paring the equivalent in solid wood.

METHODS OF TESTING GLUES

Cattle Glues. — The adoption of a standard, the selection of a sample,
and the estimate of the appearance, fracture, odor, acidity, grease con-
tent, viscosity, foam, and strength of the sample are important.

Standards. — Standards are necessary for purposes of comparison.
The Cooper glues have been used for this purpose, since those who make

418 ORGANIC STRUCTURAL MATERIALS

these glues seem able to maintain very uniform products. It is said
that the properties of these glues have remained constant during the
last fifty years.

Samples. — The selection of any sample is important. In this case.
portions drawn systematically from several parts of every package
should be mixed, ground, mixed again, and then divided so that the
final sample will weigh about six ounces.

If glues have been mixed, the parts should be separated from one
another, and each part should be tested separately. The separation
of separate fragments of dissimilar glues from one another is possible
because of color distinctions that usually exist. It is not enough to
accept the samples presented by agents; the final deliveries also should
be tested.

Appearance. — Large and irregular air bubbles indicate decomposition.
Smooth and glossy surfaces are desirable but not essential. The ap-
pearance of a glue may warrant its rejection.

Fracture. — Fractures vary with moisture and, therefore, with the
weather and is seldom a criterion. Similar pieces break differently at
different tunes. Glues made from acid-treated bones generally show
bright, clean fractures.

Odor. — Odor may be due to the character of the stock; or, it may be
due to deterioration in the glue. Glues made from goats, sheep, oxen,
and other animals, sometimes possess characteristic odors, which are
often changed as a result of boiling. The odor that arises from a hot
solution of glue should indicate any decomposition that has taken place
after the glue has been boiled.

Acidity. — The presence of acid is not an indication of the way in
which the glue was manufactured, since a little acid is sometimes added
after boiling. Sulphurous acid is often used to bleach glue and to pre-
vent its decay. A slightly acid glue is often to be preferred.

Grease. — Grease is sometimes, but not always, undesirable. The
properties of some glues, as those used for moulding, picture frames, and
some other purposes, may even be improved by the presence of grease.
Such desirability is influenced or determined by the form in which the
grease exists, which may be in large globules, or in the form of an emul-
sion. Of these two forms the latter is less objectionable. The presence
of grease may be detected as follows: A few grains of some aniline color
that will dissolve easily in water are placed on a sheet of clean white
paper. A flat brush is dipped in a warm solution of the glue, and then
hastily drained. The brush is applied to the color so as to dissolve it,
and is then, without being lifted, swept across the remaining surface
of the paper. Any grease that is present will appear in the form of
spots. Some experimenters prefer to mix the aniline color with the glue
at the start. The presence of grease in fine emulsion is not always thus

CATTLE AND FISH GLUES

419

revealed, since part of it may escape notice if the globules are finely
divided.

Viscosity. — A viscous liquid is one that moves slowly under the in-
fluence of any force. The molecules of such a liquid adhere to one
another and do not move freely among themselves.

The degree of viscosity in a solution of glue is sometimes relied upon
as an indication of strength, but is a dangerous criterion, since viscosity
may be influenced by the presence of foreign substances. For example,
a small quantity of alum will greatly increase viscosity without other-
wise improving the glue.

The degree of viscosity may be measured by noting the number of
seconds required for the passage of 50 c.c. of glue solution through the

FIG. 86. — Engler's viscosimeter.

orifice of a standard burette, pipette, or other vessel. Armour & Com-
pany test solutions prepared by dissolving one part of the glue in five
parts of water, and hold the solutions thus formed at temperatures of
150 degrees Fahrenheit while they are passing through the orifices.

Foam. — Minute bubbles usually appear when a solution of glue is
agitated. These may shortly break and disappear, or they may remain
for some time; and, in the latter case, the presence of some foreign sub-
stance, such as lime-soap, may be suspected. "Permanent foam" may
be desirable in the case of some confectioners' gelatines, but it is not
desirable in the substances now being considered.

Foam is measured in specially graduated vessels. A hot solution of
glue, placed in one of these vessels, is beaten or churned for some definite
time, such as hah" a minute. Negligible quantities of foam will shortly
disappear, while larger quantities of more "permanent foam" may reach
to the various graduations in the vessel.

Strength. — The behavior of a piece of glue while being bent is some-

420 ORGANIC STRUCTURAL MATERIALS

times taken as a criterion of its strength. It is true that a thin piece
of good glue will sometimes bend almost double without breaking, and
that, under the same circumstances, a sample of poor glue will sometimes
break or crumble. But it is also true that some weak glues are flexible,
and that some strong glues are brittle. It is not safe to estimate
strength, even approximately, by the behavior of glue during bending.

A direct method of testing cements has been suggested by Ray.1
Blocks of specially prepared porcelain are employed. One of the blocks
resembles half of a cement briquette such as is specified for testing by
the American Society of Civil Engineers, and two of the blocks, when
joined together, resemble the complete form of the said briquette. The
two blocks are glued together, and, after a sufficient time, are parted in
a Fairbanks or other testing machine. It is hard to test glue in an
ordinary wooden joint, because the glue in the joint is usually stronger
than the wood. The wood fails first, and the test serves to determine
the strength of the wood rather than that of the glue.

Strength is usually measured by comparing the solidity of a jelly
made of the glue to be tested, with the solidity of a jelly made from
glue of some standard make. The comparison may be made with a
weighted plunger of some definite area; or, the jellies may be compared
by pressing them, one after the other, with the finger. Fernbach, who
has made many tests, regards the fourth finger of the left hand as being
the most sensitive and, therefore, the most satisfactory for this work.
On the whole, the jelly strength of a glue gives the best practical indica-
tion of its strength.

Fish Glues. — Less attention has been given to perfecting methods
for testing fish glues. The means that manufacturers have for grind-
ing these glues, and for judging their qualities, are apparently suf-
ficient. The fact that fish glues are sold under labels is a safeguard
to consumers.

Thesis, New York University, 1902.

CHAPTER XVII

INDIARUBBER AS A STRUCTURAL AND MACHINE MATERIAL.

SOURCES, PREPARATION, PROPERTIES, AND USES OF

INDIARUBBER

The fact that rubber is used to some extent in construction,
transportation, and manufacture, as in flooring, automobile
tires, and belts, is sufficient to warrant it's rating as a structural
and machine material.

As sugar is known to exist in a variety of non-related and dis-
similar plants, such as sugar beets, sugar cane, and sugar maple
trees, so the constituents of the tough, impermeable, and very
elastic substance known as Indiarubber, are known to exist in a
number of plants that are not related to one another.

The trees, vines, and shrubs in which the constituents of India-
rubber are known to be present may be numbered by the hundred ;
but the trees, vines, and shrubs from which it is actually obtained
in commercial quantities are comparatively few. The plants
from which rubber is thus obtained grow in a belt that extends
around the world. This belt includes parts of Mexico, Central
America, South America north of Argentina, Africa from Cape
Colony to Sahara, Oceanica, Java, Sumatra, Borneo, India,
The Malay States, and the Philippines.

The constituents of Indiarubber exist in a milk-like fluid or
latex that is present in and characteristic of most of the plants
from which Indiarubber is obtained. The latex itself, the
methods by which it is collected, and those by which it is made to
yield rubber, are all-important.

REFERENCES. — " Crude Rubber and Compounding Ingredients," Pearson
(Indiarubber Publishing Company, New York, 1909) ; Files of Indiarubber
World; Journal of Society of Chemical Industry; "The Culture of the Cen-
tral American Rubber Tree," Cook (United States Bureau of Plant In-
dustry, Bulletin No. 49); "Rubber Cultivation for Porto Rico," Cook
(United States Division of Botany, Circular No. 28); "Indiarubber"
(Special Consular Reports, Government Printing Office, 1892); "Guayule,
A Rubber Plant of the Chihuahuan Desert," Lloyd (Carnegie Institution,
Bulletin No. 129); "Indiarubber and Gutta Percha," Seeligmann, Torril-
hon and Falconnet (Scott, Greenwood & Company, London, 1910);
"Rubber," Schidrowitz (Methune & Company, London, 1911).

421

422

ORGANIC STRUCTURAL MATERIALS

Latex. — This term applies generally to the milky juice secreted
by certain shrubs, vines, and trees, In some cases the latex
yields no rubber; in others it does yield rubber, but this is not

FIG. 87. — Appearance of Hevea rubber latex.

used.1 Still other latex is known by experience to produce rubber
satisfactorily.

1 The latex of the common milkweed is a familiar example. When this
fluid dries upon the fingers it yields an elastic, sticky substance which con-
tains resins, other compounds and a residue, the empirical composition of
which is the same as that of crude rubber.

INDIARUBBER 423

Latex must be distinguished from sap. The latter fluid occu-
pies a large proportion of the entire stem, and is common to all
plants; while latex, which is restricted to certain species, is con-
fined in delicate tubes that run lengthwise throughout the inner
part of the bark. Sap is obtained by boring holes through the
bark and outer sapwood; while latex is obtained by cutting across
the bark alone.

The appearance of latex is similar to that of cow's milk. It
is a thin, watery emulsion, made up of cream-like globules sus-
pended in a thinner liquid of another composition. These two
parts remain mingled in emulsion until certain physical or
chemical changes cause them to separate. The creamy part of
latex obtained from the plants of the Indiarubber series is the
basis of indiarubber.

It is not known whether rubber exists as such in the latex,
or whether it is due to recombinations caused by chemical or
physical changes. It is enough to assume that rubber exists in
the latex much as butterfat exists in cream, and that it is obtained
from the latex by chemical or other manipulations that suggest
the churning to which butterfat is subjected during the preparation
of butter.

The proportions of rubber in the latex vary considerably. The
composition of a sample of Ceylon Para latex, described in the
Encyclopedia Britannica, was as follows:1 Water, 55.15 per
cent.; Caoutchouc (rubber), 41.29 per cent.; Proteids, 2.18
per cent.; Sugar, etc., 0.36 per cent.; Ash (salts), 0.41 per cent.
The best latex may yield as much as 50 per cent, of rubber.
Cook states that six pounds of fresh rubber were obtained from
ten pounds of latex, but that this rubber shrank to three pounds
before the end of the year.2

Collection of Latex. — Details vary with species and localities.
Some plants produce larger quantities of latex and then require
rest, while others yield smaller quantities at a time but yield
these smaller quantities frequently. The comparative advan-
tages of longitudinal, oblique, transverse, and spiral cuts, and
of tools used to make these cuts, have received much attention.
The object is to so adjust time and frequency of tapping with
the peculiarities of species as to secure maximum yields during

1 Quoted by permission of The Cambridge University Press.

2 "The Culture of the Central American Rubber Tree," Cook (United
States Bureau of Plant Industry, Bulletin No. 49, p. 75).

424 ORGANIC STRUCTURAL MATERIALS

the longest possible terms with the least possible harm to the
trees.

Pearson describes the collection of wild Para rubber as follows :

FIG. 88. — Application of coagulant (alcohol) to latex shown in preceding

figure.

"A man locates from 100 to 150 rubber trees and cuts a narrow path
through the jungle from tree to tree. He starts out early in the morning
with a little hatchet and an armful of tin cups. He makes a few cuts
on each tree and sticks the cups under to catch the latex. . . . The
next day he goes through the same operation on the same trees, making
fresh cuts. He continues this for several weeks, sometimes months.
More than this, he taps the same trees year after year for many years."

INDIARUBBER

425

Rubber Obtained from Latex. — The process by which rubber is
obtained from latex is called coagulation. This term is used in
all cases, even although the underlying changes may differ with

FIG. 89. — Result obtained by addition of alcohol to latex shown in Fig. 88.
The white tint of the resulting rubber soon gave way to characteristic
darker color and the mass became denser and much smaller.

the processes employed and with different species of latex. The
phenomena of coagulation are not yet perfectly comprehended.
Some kinds of latex coagulate spontaneously like blood, while
others coagulate after fermentation like milk; still other kinds

426 ORGANIC STRUCTURAL MATERIALS

of latex coagulate after the addition of chemicals, and some do
not coagulate at all. Among the materials . and agencies em-
ployed to obtain rubber from latex are acetic acid, air, alcohol,
alum, heat, lime, lime-juice, proprietary compounds, smoke and
sunshine. The accompanying pictures show the effect of alcohol
upon latex.

An exception to the rule that rubber is derived from latex
should be noted. The rubber known as Guayule is distinct from
most others because it is not derived from latex, the rubber
existing as such in the cells of the plants. This rubber cannot be
obtained by customary tapping and coagulating. It is either
dissolved out by suitable chemical solvents, after the tissues in
which it is contained have been ground in a mill ; or else, the mass
is agglomerated, either with or without the assistance of some
substance like caustic potash that will attack the walls of the
cells that contain the rubber.1

Much of the best wild Para rubber is obtained by exposing the latex
to the smoke of burning palm nuts (usually Attalea excelsa). A wooden
paddle is dipped into the vessel containing the latex and the thin layer
that collects upon the paddle is exposed to the smoke. In some districts
coagulation is obtained by spreading the latex over the banana-like
leaves of a species of Calathaea, and then exposing it to the sun and air.
Cook states2 that the natives of Angola rely upon the fact that much
Landolphia latex changes almost immediately upon exposure to the at-
mosphere, and obtain considerable rubber by smearing this latex over
their bodies; the rubber is cut away as soon as the accumulation is
sufficiently thick. There are many other ways by which latex can be
coagulated.

GRADES OF INDIARUBBER. Indiarubbers may be grouped
or classified in several ways. Some of these are as follows:

Geographical Classification. — From this standpoint rubbers may
be classified according as they come from major areas such as
the Para, Central American, African, and East Indian districts,
and also as they come from fields within these major districts.
Also rubbers are named from collecting stations, or trading points
that are located within these minor fields.

1 " Guayule, A Rubber Plant of the Chihuahuan Desert," Lloyd (Published
by Carnegie Institution).

2 "Rubber Cultivation for Porto Rico," Cook (United States Division of
Botany, Circular No. 28, p. 9).

INDIARUBBER 427

Para rubber was formerly divided according as it came from the valley
of the Upper Amazon and from islands in the Lower Amazon, into Up-
river and Island Para. There are now Caviana, Cameta, Madeira,
Manaos, Purus, and many other kinds of Para rubber. Central Ameri-
can Rubber, or " Centrals," includes Nicaraguan, Guatemalan, Mexi-
can, Honduras, West Indian, and other yields; and each one of these
includes others, as for example, Colombian rubber includes Cartagena,
Panama, and other kinds. African rubber is divided according as it
comes from French West Africa, Sierra Leone, Liberia, Gold Coast Col-
ony, French Congo, Belgian Congo, East Africa, Madagascar, and other
districts. East Indian rubber includes Rangoon rubber, which is a
product of Burma exported through the port of Rangoon, Java rubber,
and rubber from Borneo and other places.

Botanical Classification. — The plants known to contain
rubber are too numerous to name in the present connection.
The plants from which it is actually obtained in commercial
quantities may be divided as they are trees, vines, and shrubs.

Tree Rubber. — The Para or Hevea Rubber Tree (Hevea braziliensis)
stands first among all plants of every description that produce India-
rubber. This tree, which is the source of most Para rubber, is a native
of Brazil but has been transplanted in many places on both hemispheres.
Its value depends upon the quality of its rubber, and also upon the fact
that it can be tapped every day for long intervals. Other important
trees that yield Indiarubber are the Central American Rubber Trees
(Castilloa alba, Castilloa elastica and others), and the Assam Rubber
Tree (Ficus elastica) which is a native of India, Burma, and the Malay
Archipelago.

Vine Rubber. — A large part of the supply from Africa is obtained
from rubber-bearing vines and creepers, of which there are many species
(Landolphia owariensis, Landolphia heudelotii, Landolphia kirkii, Lan-
dolphia dawei, Landolphia thollonii and others).

Shrub Rubber. — The Guayule (Parthenium argentatuni) has already
been mentioned.1 This shrub flourishes over considerable areas in the
dry regions of northern and central Mexico and in adjoining parts of
Texas, Arizona, and New Mexico, and differs from most rubber produc-
ing plants in that the rubber exists as such in its cells. Special methods
are employed to obtain this rubber, and their discovery has caused this
shrub to become very valuable.

Crude and Refined Rubber. — The first term includes
material as it arrives from the forests. Such rubber is distin-

1 "Guayule, A Rubber Plant of the Chihuahuan Desert," Lloyd (published
by the Carnegie Institution, pp. 8, 9, and 177).

428 ORGANIC STRUCTURAL MATERIALS

guished by the presence of smaller or larger quantities of twigs,
bark, dirt, and other impurities that must be removed before
the rubber can be used, after which removal the product is known
by the second term, that is, as Refined rubber. The shapes of
the pieces in which crude and refined rubber are presented are
characteristic.

Fresh and Reclaimed Rubber. — The second term includes
rubber obtained from worn-out and discarded rubber articles.
This product is so important, that, for some time past in the
United States, two pounds of it have been used to one of fresh
rubber. Without Reclaimed rubber the shortage in the produc-
tion of Fresh rubber would often have been serious. A mixture
of fresh and reclaimed rubber is cheaper, and, in some cases,
better than fresh rubber alone. Reclaimed rubber is often called
according to its origin. Thus, there are tire-tread, hose, gum-
shoe, and other kinds of stock. The first term, that is, Fresh
rubber, includes all that is not Reclaimed rubber.

Wild and Plantation Rubber. — Wild rubber is that which
is obtained by more or less primitive processes from plants grow-
ing naturally in the forest. It is usually quite dirty and there
are other defects, yet- some of the best rubber is of this kind.
At the present time, the larger part of the world's supply of rub-
ber is Wild rubber.1

Plantation rubber is obtained from cultivated trees. Tapping,
coagulating, and other details are attended to in a more or less
scientific manner. Plantation rubber is frequently branded with
the trademark of the planter who then assumes responsibility
for the quality of his product. The quantity of this kind of
rubber is increasing every year; yet, much remains to be learned
with regard to it. It is known that some species do well in some
localities, and fail utterly in others, and that some individual
trees grow well and yet fail to produce satisfactory quantities
of latex. There are many ways in which failures may take
place, but, in spite of this, as the following table (Pearson) shows,
rubber planting is increasing very rapidly in the Far East.

1 It should be noted that the wild rubbers received at the present time are
for the most part Para rubbers, and that in spite of the crude methods em-
ployed to collect and prepare them, the various grades of Para rubber are
quite good and uniform in quality. This cannot be said of much of the
plantation rubber noted in the succeeding paragraph. Medium grade
plantation rubbers often exhibit wide variability. High-grade plantation
rubbers are, however, quite uniform in quality.

INDIARUBBER

429

Ceylon,
pounds

Federated Malay
States,
pounds

Total,
pounds

1903

41,798

41,798

1904

77,212

77,212

1905

168,547

228,800

397,347

1906

327,661

1,028,792

1,356,453

1907

566,080

2,089,085

2,655,165

1908

912,125

3,671,435

4,583,560

1909

1,372,416

7,390,643

8,763,059

To August 15, 1910

1,468,146

7,512,102

8,980,248

Classification Due to Form. — The sizes and shapes of pieces
in which rubber is originally marketed vary greatly. Some forms
are associated with peculiar processes or conditions, or with
certain districts, or species. For example, much plantation
rubber is received in rough-surfaced sheets known as crepe.
Rubber from Sierra Leone is received in forms known as twists,
cakes, and niggers. There are also many other forms, such as
thimbles, balls, nuts, lumps, flake, paste, -buttons, oysters,
biscuits, tongues, blocks, worms, strips, sheets, scrap, and lace.

PREPARATION AND PURIFICATION OF RUBBER.— The
process employed to free crude rubber from mechanical impuri-
ties is called washing. The rubber is first soaked in very hot
water and- is then passed again and again between corrugated
rollers of special machines that tear and break it. At the same
time streams of water are made to flow over the rubber and these
streams carry away the impurities that are exposed by the
tearing action of the rolls.

Rubber treated in this way is comparatively clean, but much
water is retained. It is, therefore, submitted to the rollers of
another machine which press it into comparatively thin sheets,
in which form it is ready to be dried. The sheets are either
dried slowly by natural means, or they are dried rapidly under
high temperatures in rooms prepared for the purpose.

From this point details vary more greatly as different objects
are to be attained. For example, the rubber must be "mixed."
Aside from the sulphur used for vulcanization, rubber is seldom
used alone, but other substances are added, the object being to
reduce the cost of the rubber without destroying its usefulness,
or to give it characteristics that cannot be secured in any other
way. Sulphur, zinc white, white lead, whiting, oils, rubber sub-

430

ORGANIC STRUCTURAL MATERIALS

stitutes, and many other materials and compounds are used in
this connection.

Several machines are necessary. A warming mill or " warmer" is a
set of rolls, within which steam circulates. The mill causes the rubber
to become soft, homogeneous, and ready for mixing. The incorporation
of the several ingredients with one another is accomplished in a mixing
machine or "mixer" designed for this purpose. A " calender" is a mill
by which the prepared rubber is formed into sheets from which it "can
be more easily made into the desired shapes and sizes. There are
many combinations and details.

FIG. 90. — Calender with coil clutch motor drive.1

Vulcanization. — The fact that pure rubber is influenced by
comparatively moderate changes of temperature led to experi-
ments that resulted in the discovery of the process called " vul-
canization. " This discovery, made by Goodyear in 1844, con-
sists, briefly, of subjecting rubber to the influence of sulphur.
The exact nature of many details is not always divulged by
manufacturers. Practically all rubber is now vulcanized.

The details of the processes employed to secure vulcanization
vary greatly. Many objects are to be attained and details
known to secure the results desired are followed. Primarily,
vulcanization processes may be grouped as they are Heat
Processes and Non-heat Processes.

Photograph, Farrel Foundry & Machine Company.

INDIARUBBER 431

Heat Processes. — The heat may be wet or dry. In the first case,
articles, such as sheetings, are covered with French talc, so that they
will not adhere to one another, or are wrapped in cloth, and are then
subjected to the action of live steam. Time, temperature, and pressures,
which latter are above that of the atmosphere, are important. In the
second case, articles, such as shoes, coats, and other black goods, are
cured in dry, hot air or are confined in moulds and then placed in a
steam press. Sometimes rubber is cured and moulded at the same time.
This is the case with rubber belts that are cured while being moulded
between the platens of special presses.

About six per cent, of sulphur, based upon the weight of the rubber,
is used in the vulcanization of the majority of articles prepared for
mechanical purposes. Press-cured articles often contain as much as
eight per cent, of sulphur. In the case of rubber shoes the amount of
sulphur used is three per cent., based upon the weight of the rubber.
Larger quantities are used in the preparation of the hard rubber known
as "vulcanite" or " ebonite." As a rule more sulphur is used than is
needed to combine with the rubber. The excess of uncombined sulphur
that remains after vulcanization is distributed in extremely small glob-
ules throughout the mass, and eventually appears upon its surface as a
grayish powder. In this connection, it should be noted that results are
often influenced as much by the time and temperature of vulcanization
as by the quantity of sulphur.

No action takes place between the rubber and the sulphur until the
temperature reaches about 120 degrees C., and, even then, the action
proceeds slowly; but the action goes forward more rapidly as tempera-
tures increase, particularly in the presence of much sulphur. The tem-
peratures required during the preparation of mechanical goods vary
between 120 degrees C. and 150 degrees C. Hard rubber or vulcanite
may require higher temperatures.

Non-heat Processes. — These are of two kinds: acid vulcanization is
accomplished by dipping the prepared rubber in a solution of sulphur
chloride and carbon bisulphide, and then treating it with an alkaline
wash; while vapor vulcanization is obtained by subjecting the rubber
to the fumes of sulphur chloride, later replaced by those of ammonia.
Articles to be vulcanized by these methods must be thin, since otherwise
the liquids do not penetrate. Cold vulcanization usually results in soft,
velvet-like surfaces, but articles treated by this method are not always
durable.

PHYSICAL AND CHEMICAL PROPERTIES OF RUBBER.

— Crude rubber is tough, pliable, impermeable to water and
gases, and a very poor conductor of electricity. Its most char-
acteristic property is elasticity; that is, its ability to return to

432 ORGANIC STRUCTURAL MATERIALS

about its original dimensions after it has been stretched through
a distance many times its original length.

The base of crude rubber is chemically Pure Rubber, which,
in many places, is distinguished by the name Caoutchouc. It
should be noted that the name Caoutchouc has two meanings.
First, as already stated, the meaning is frequently restricted to
chemically pure rubber; but, second, it is also used as a synonym
for crude rubber; that is, for pure rubber with its associated
compounds. The formula of pure rubber, or Caoutchouc,
CioHie, is so approximate and general as to be of little use. The
same formula applies to gutta percha.

Besides Caoutchouc, crude rubber contains resins, the functions of
which are not understood, although it is probable that they exert an
influence upon vulcanization. Nitrogenous substances, proteins, and
peptones, the functions of which, like those of resins, have not been
thoroughly investigated, are also present. Other ingredients may be
grouped as carbohydrates, refuse, such as dust and bark, moisture, and
materials or compounds introduced by coagulating processes. It should
be remembered that crude rubber is, in large part, a mixture containing
parts of practically all of the constituents that existed in the latex from
which the rubber was prepared. From this viewpoint it may be re-
garded as, proportionately, a chemical combination within the mass of
which other substances or compounds have become mechanically en-
tangled. Analyses of crude rubber vary with the character of the latex
from which it was prepared, and with the methods employed during the
processes of coagulation.

REFERENCES. — "Der Kautschuk und Seine Prtifung," Hinrichsen and
Memmler (Leipzig, Hirsel, 1910); "Synthetic Caoutchouc, A Review Com-
piled from the Literature," Barrows (The Chemical Engineer, September,
1911, p. 355); "Production and Polymerization of Butadiene, Isoprene and
their Homologues," W. H. Perkin, Jr. (Journal Society Chemical Industry,
Vol. 31, p. 616, 1912); "Les Produits pour le Fabrication du Caoutchouc
Synthetique," Ditmar ("Le Caoutchouc et la Gutta Percha," Paris, Vol. IX,
p. 6458, 1912); "Les Caoutchoucs Artificiels," L. Ventou-Duclax (Dunot
and Pinat, Paris, 1912); "Die Synthese des Kautschuks," Ditmar (Theo.
Steinkopff, Dresden and Leipzig, 1912); "The Business Aspect of Synthetic
Rubber," Hinrichsen (Scientific American, August 3, 1912, p. 99); "Chem-
istry of the Rubber Industry," Potts (Constable and Company, London,
1912); "Natural and Synthetic Rubber," F. M. Perkin (Journal Royal
Society Arts, London, Vol. 61, p. 86, 1913); "Review of Pioneer Work on
Synthesis of Rubber," Pond (Journal American Chemical Society, January,
1914, p. 165); "The Chemistry of Rubber," Porritt (D. Van Nostrand
Company, New York, 1915).

INDIARUBBER 433

Crude rubber is influenced by moderate changes in tempera-
ture. Heat causes it to soften and become more or less sticky
or " tacky"; sheets submitted to higher heat in dry-rooms de-
signed to dissipate moisture absorbed during cleansing some-
times soften so greatly that they drop from the supports upon
which they are hung. Crude rubber loses most of its elasticity
when placed in boiling water, but hardens and becomes elastic
again as soon as it is allowed to cool. It melts at about 250
degrees F. and becomes a viscous fluid that does not harden again;
while higher temperatures cause decomposition with the forma-
tion of various liquid hydrocarbons. It is sensitive to low tem-
peratures; and, when subjected to excessively low tempera-
tures such as those caused by liquid air, it loses all elasticity and
may then even be powdered.

Crude rubber is insoluble in water and alcohol, and is but
slightly acted upon by dilute acids. The effect of dilute alkaline
solutions is, however, quite pronounced. Such solutions exert
a marked depolymerizing action upon the rubber, which becomes
much softer, and if the subjection to the alkaline solution is
excessive, stickiness and tackiness may result. Crude rubber
is soluble in turpentine, petroleum spirits, carbon disulphide,
carbon tetrachloride, and some other liquids the comparative
importance of which is much in the order mentioned. These
liquids are used, either alone or in mixtures, whenever it is
necessary to dissolve rubber.

Crude rubber is subject to oxidation, which causes it first to
become soft, and then to become hard, brittle, and useless.
This phenomenon, which is technically known as " perishing,"
is thought to be influenced by light, heat, and the constituents
of the rubber itself. Under certain conditions, vulcanized rubber
behaves in a similar manner, but in such cases the changes are
possibly influenced to some extent by fillers employed to secure
certain physical characteristics.

Crude rubber responds to the influence of certain chemical
substances. The changes that take place when rubber is joined
with sulphur in vulcanization have been noted. These changes
are of a chemical nature. As distinct from these changes, how-
ever, crude rubber is able to take up, more or less mechanically,
certain powders, such as litharge, powdered coal, and the salts
of aluminum and of iron, and to form with them homogeneous

434 ORGANIC STRUCTURAL MATERIALS

masses with colors and other properties influenced correspond-
ingly by the character of the fillers used.

Some of the more characteristic mixing ingredients and fillers
are as follows:1 Vulcanizing Agents; sulphur and sulphur
chloride. A ccelerators of Vulcanization; litharge, calcium hydrate,
magnesium oxide or carbonate. Colorless Fillers; whiting, ba-
rium sulphate, lithopone, French chalk, and zinc oxide. Colored
Fillers; antimony, arsenic or mercuric sulphides, red lead, lead
peroxide, ferric oxide, chromic oxide, lead chromate (cold cure),
ultramarine, Prussian blue (cold cure), graphite, and lamp-black.
Organic Fillers; paraffin wax, pitch, rosin, tar, and rubber sub-
stitutes (white and brown).

From a chemical viewpoint, vulcanized rubber is principally
distinguished from crude rubber by being cleaner, as well as by
the presence of sulphur and of fillers used to influence physical
properties and give colors to final products. From the physical
viewpoint, vulcanized rubber is much more stable than crude or
pure rubber. It is not influenced by moderate changes in tem-
perature, and is more elastic and in every way better than crude
rubber. The improvement caused by vulcanizing is so great that
practically all rubber is now subjected to this process. Vul-
canized rubber may be soft or hard.

Soft vulcanized rubber, which is obtained by limiting the
quantity of sulphur and by using comparatively little heat, is
used for such articles as pencil erasers and tubing. Hard vul-
canized rubber, obtained by using larger proportions of sulphur
and higher degrees of heat, is called " vulcanite" and " ebonite."
This product resembles horn or celluloid and is used for such
articles as combs and buttons. The name " semi- vulcanite "
is sometimes applied to products that stand between these
extremes.

THE USES OF RUBBER. — Rubber is used in flooring, auto-
mobile tires, belts, and machine foundations. In electrical
science, it is used as an insulating material; while its value as a
waterproofing agent is of fundamental importance. It also
enters into hose, surgical goods, sporting goods, cements and other
groups of articles and compounds. For many purposes satis-
factory substitutes for rubber do not exist.

1 See "Chemistry of Rubber," Porritt (p. 42).

INDIARUBBER 435

Synthetic Rubber

Synthetic rubber is the result of a purely chemical process.
In composition and in properties it is equivalent to, or the same
as, natural rubber. Thus far synthetic rubber is a scientific truth
rather than a practical success. The fact that artificial rubber
can be prepared in laboratories, and that such rubber is practi-
cally identical with that obtained from trees, is beyond question;
but the cost of such rubber is yet so high that very little of it is
manufactured .

The ultimate value of synthetic rubber must obviousty depend
upon its cost and quality. Assuming the quality to be satisfac-
tory, methods will have to be devised whereby parent substances
can be prepared in larger quantities and more cheaply than at
present. The problem is complicated by the fact that, with
present knowledge, it seems necessary that parent substances
should be particularly pure.

It has long been known that an intimate relationship exists between
indiarubber and a group of substances, of which isoprene and butadiene
are at present the most notable. In 1860, Williams isolated what is
now known as isoprene, from products obtained from the destructive
distillation of rubber. In 1875, Bouchardat suggested that under cer-
tain conditions isoprene might be converted back again into rubber. In
1892, Tilden discovered that some old specimens of isoprene obtained
from turpentine had converted themselves into rubber without assist-
ance; and, in 1909, Hofmann and others suggested the methods that
are now employed.

Isoprene is obtained in several ways, as from fusil oil, and by condens-
ing vapors of turpentine over iron at temperatures of from 55° degrees
C. to 600 degrees C. (English patent 27908 of 1909). Butadiene is also
obtained in several ways, as from products obtained by fermenting the
dried pulp of potatoes (Detoeuf, Nature, 1912, p. 306). Of the two
parent substances mentioned, isoprene is a colorless liquid-hydrocarbon
in which the hydrogen and carbon exist in the same proportions as in
ordinary rubber. The transformation of isoprene to rubber is obtained
by placing isoprene, selected for its purity, under pressure, and then
heating it, with or without the intervention of other substances. Or
else, it is transformed by the influence of small quantities of other sub-
stances, as metallic sodium.1

1 Such a change is due to polymerization, which has been denned as the
apparent fusion or union of two or more molecules, into a more complex
molecule with a higher molecular weight and somewhat different physical
and chemical properties (Century Dictionary).

BIBLIOGRAPHY

INTRODUCTION, CHAPTERS I AND II

Conservation. General. — " Conservation Natural Resources of the United
States," Van Hise (The Macmillan Company, 1910); "Conservation of
Water by Storage," Swain (Yale University Press, 1915); Files of Engineer-
ing News, Engineering Record, American Forestry; Transactions American
Society of Civil Engineers; etc., etc.

Botanies. Anatomy and Physiology of Trees. — "Principles of Botany,"
Bergen and Davis (Ginn & Company); "A Practical Course in Botany,"
Andrews (American Book Company, 1911); "Plants," Coulter (D. Apple-
ton & Company) ; " Outlines of Botany," Leavitt (American Book Company) ;
"Practical Botany," Bower (The Macmillan Company); "Manual of
Botany," Gray (Seventh Edition); "Plant Anatomy," Stevens (P. Blakis-
ton's Son & Company); "Plant Physiology," Jost (Gibson, Oxford, 1907);
"Textbook of Botany," Strasburger; "Forestry for Farmers," Fernow
(United States Forest Service, Farmers Bulletin No. 67); "First Book of
Forestry," Roth; "Manual of Trees of North America," Sargent; "Hand-
book of Trees of the Northern States and Canada," Hough; "Silva of North
America," Sargent; "Cyclopedia of American Horticulture," Bailey;
"North American Trees," Britton and Shafer; Files of Botanical Gazette;
Files of American Forestry; Files of Forestry Quarterly; etc., etc.

Forestry. — "Forestry for Farmers," Fernow (United States Forest
Service, Farmers Bulletin No. 67); "First Book of Forestry," Roth (Ginn &
Company, 1902); "Practical Forestry," Gifford (D. Appleton & Company,
1903); "Primer of Forestry," Pinchot; "Conservation of Natural Resources
in the United States," Van Hise (The Macmillan Company); Files of
American Forestry and Forestry Quarterly; Publications of United States
Forest Service; "Histology of Medicinal Plants," Mansfield (John Wiley
& Sons, 1917), etc.

1 The names "Division of Forestry" and "Bureau of Forestry " have been
used by the National Government to denote what is now its "Forest
Service."

437

438 ORGANIC STRUCTURAL MATERIALS

CHAPTER III

Identifications. — Cellular Structure of Wood. Character and Arrange-
ment of Wood-elements. "Structure of Certain Timber Ties, etc.,"
Dudley (United States Forest Service, Bulletin No. 1); " Timber, "Roth
(United States Forest Service, Bulletin No. 10); "The Decay of Timber,"
von Schrenk (United States Bureau of Plant Industry, Bulletin No. 14,
p. 12); Tiemann (Trans. American Railway Engineering Association, Bul-
letins No. 107 and No. 120); "North American Gymnosperms," Penhallow;
"Outlines of Botany," Leavitt (American Book Company); "Materials of
Construction," Johnson; "Plant Anatomy," Stevens (P. Blakiston's Son
& Company); "Wood," Boulger (London, Second Edition); "Pithray Flecks
in Wood," Brown (United States Forest Service, Circular No. 215); "Resin
Canals in White Fir," Mell (American Forestry, June, 1910); "Textbook
of Botany," Strasburger; "Chemistry and Physics of Building Materials,"
Munby; " Identification of Important American Oak Woods," Sud worth and
Mell (United States Forest Service, Bulletin No. 102); " Confusion /of
Technical Terms in Study of Wood Structure," Mell (Forestry Quarterly,
Vol. IX, 1911, No. 4); "Identification of Economic Woods of United
States," Record (John Wiley & Sons, 1912).

CHAPTER IV

The Trunk: Bark, Sapwood and Heartwood, Annual Layers, Imperfec-
tions.— "Plant Anatomy," Stevens (P. Blakiston's Son & Company,
1910); "Plant Physiology," Jost (Oxford Press, 1907); "Age of Trees and
Time of Blazing Determined by Annual Rings," Fernow (United States
Division of Forestry, Circular No. 16, pp. 2, 3 and 6); "Rules and Specifica-
tions for the Grading of Lumber Adopted by the Various Manufacturing
Associations of the United States, " (United States Forest Service, Bulletin
No. 71).

CHAPTERS V, VI, VII, VIII

Nomenclature. Localities. — "Check List of Forest Trees of the United
States," Sud worth (United States Forest Service, Bulletin No. 17); "Man-
ual of the Trees of North America," Sargent (Houghton, Mifflin & Com-
pany); "Wood," Boulger (Edward Arnold, London, Second Edition); "Die
Pflanzengattungen, Geographische Verbreitung, Anzahl und Verwandschaft
aller bekannten Arten und Gattungen im Pflanzenreich," J. C. T. Uphof
(Leipzig, 1910).

Descriptions of Trees. — "Silva of North America," Sargent; Vol. IX,
Tenth United States Census; "Cyclopedia of American Horticulture,"
Bailey and Miller; "Illustrated Flora of the Northern United States, Can-
ada, and the British Possessions," Britton and Brown (1896-98); "Manual
of the Trees of North America Exclusive of Mexico," Sargent; "Handbook of
the Trees of the Northern States and Canada," Hough; "The Foresters'
Manual," Ernest Thompson Seton; Publications of the United States Forest
Service and other Bureaus of the United States Department of Agriculture.

BIBLIOGRAPHY 439

Descriptions of Woods. Structural Qualities. — "Silva of North Amer-
ica," Sargent; " American Woods" (actual sections), Hough; Jesup Collec-
tion of Woods at Museum of Natural History, New York City; Vol. IX,
Tenth United States Census; " Inspection of Materials and Workmanship,"
Part 1, Kidder; "The Materials of Construction," Johnson; "Timber and
Timber Trees," Laslett (London); "Timbers of Commerce," Stone (London);
Report on Forests of Western Australia," J. Ednie Brown; Publications
Baron Ferd. von Mueller; "Important Philippine Woods," Captain Ahern, IT.
S. A.; "Wood," Boulger (Second Edition, London); "American Lumber in
Foreign Markets" (Special Consular Reports, Vol. XI, United States State De-
partment); Publications of American Railway Engineering Association; Files
of Engineering News; Files of Engineering Record; Proceedings of American
Society for Testing Materials; Publications of the United States Forest Ser-
vice and other Bureaus of the United States Department of Agriculture,
(specific documents are mentioned in connection with the woods described) ;
"Mechanical Properties of Wood," Record (John Wiley & Sons, 1914); see
also list under "Physical Properties of Woods."

Uses of Wood. — "Catalogue of the Jesup Collection," Sargent; Files of
American Lumberman (Chicago), The Lumber Trade Journal (New Or-
leans), The New York Lumber Trade Journal, The Southern Lumberman
(Nashville, Tenn.), The Lumber World Review (Chicago), The Hardwood
Record (Chicago), American Forestry, Engineering News and Engineering
Record; Publications American Railway Engineering Association; Proc.
American Society for Testing Materials; Vol. IX, Tenth United States Cen-
sus; "Uses of Wood," Roth (Department of Agriculture Yearbook, 1896);
"A Study of the Wisconsin Wood-using Industries," Smith (Published State
Department of Forestry, Madison, Wis.); "The Wood-using Industries of
Illinois," Simmons (Published Department of Horticulture, University of
Illinois); "The Wood-using Industries of Maryland," Maxwell (Published
Maryland State Board of Forestry); "Forest Products of the United States"
(Bureau of Census, 1909); Publications Office of Wood Utilization (United
States Forest Service) ; Other publications of the United States Department
of Agriculture; specific documents are mentioned in connection with the
woods described.

CHAPTER IX

Physiological, Chemical, and Physical Properties of Woods. — "Physio-
logical Roll of Mineral Nutrients," Loew (United States Division Vegetable
Physiology and Pathology, Bulletin No. 18, 1899); "Plant Physiology,"
Jost (Gibson, Oxford, 1907); United States Dispensatory; " Microchemistry
of Plant Products," Stevens (Plant Anatomy, pp. 330-367); "Sap in Rela-
tion to the Properties of Woods," Record (Proc. American Wood Preservers
Association, Baltimore, Md., 1913, pp. 160-166); Vol. IX, Tenth United
States Census; Executive Document No. 5, Forty-eighth Congress, First
Session; "Applied Mechanics," Lanza; "Materials of Construction," John-
son; "Timber Physics, Part 1, Preliminary Report" (United States Forest
Service, Bulletin No. 6, 1892); "Timber Physics, Part 2, Progress Report"
(United States Forest Service, Bulletin No. 8, 1893); "Report on Preserva-

440 ORGANIC STRUCTURAL MATERIALS

tive Processes and Metal Tie Plates for Wooden Ties," Tratman (United
States Division of Forestry, 1894); " Timber," Roth (United States Forest
Service, Bulletin No. 10, 1895); " Southern Pine — Mechanical and Physical
Properties" (United States Forest Service, Circular No. 12, 1896);" Timber
Pines of the Southern United States" (United States Forest Service, Bulletin
No. 13, 1897); "Summary of Mechanical Tests on Thirty-two Species of
American Woods" (United States Forest Service, Circular No. 15, 1897);
"The Efficiency of Built-up Wooden Beams," Kidwell (Trans. American
Institute of Mining Engineers," July, 1897); "American Railway Bridges
and Buildings," Berg (Proceedings of the Association of Railway Superin-
tendents of Bridges and Buildings, 1898); "Economical Designing of Timber
Trestle Bridges," Johnson (United States Forest Service, Bulletin No. 12,
1902); "Tests on the Physical Properties of Timber," Olmsted (United
States Department of Agriculture Yearbook, 1902); Transactions of the
American Society of Civil Engineers, (Vol. LI, 1903); "Progress Report on
the Strength of Structural Timber," Hatt (United States Forest Service,
Circular No. 32, 1904); "Cross Tie Forms and Rail Fastenings with Special
Reference to Treated Timbers," von Schrenk (United States Bureau of For-
estry, Bulletin No. 50, 1904); "Instructions to Engineers of Timber Tests,"
Hatt (United States Forest Service, Circular No. 38, 1906); "Experiments
on the Strength of Treated Timber," Hatt (United States Forest Service,
Circular No. 39, 1906); "Holding Force of Railroad Spikes in Wooden Ties,"
Hatt (United States Forest Service, Circular No. 46, 1906); "The Red
Gum," Chittenden (United States Forest Service, Bulletin No. 58, 1906);
"Effect of Moisture upon the Strength and Stiffness of Wood," Tiemann
(United States Forest Service, Bulletin No. 70, 1906);" The Strength of
Wood as Influenced by Moisture," Tiemann (United States Forest Service,
Circular No. 108, 1907); "Second Progress Report on the Strength of
Structural Timber," Hatt (United States Forest Service, Circular No. 115,
1907); "Organization, Equipment, and Operation of the Structural Mater-
ials, Testing Laboratories at St. Louis, Missouri," Humphreys (United
States Geological Survey, Bulletin No. 329, 1908); "Tests of Vehicle and
Implement Woods" (United States Forest Service, Circular No. 142,
1908); Tests of Timber Beams," Talbot (University of Illinois, Bulletin
No. 41, 1909); "Properties and Uses of Southern Pines," (United States
Forest Service, Circular No. 164, 1909); "The Commercial Hickories"
(United States Forest Service, Bulletin No. 80, 1910); "Utilization of
California Eucalyptus" (United States Forest Service, Circular No. 179,
1910); "Properties and Uses of Douglas Fir" (United States Forest
Service, Bulletin No. 88, 1911); "Strength Values for Structural Timbers,"
Cline (United States Forest Service, Circular No. 189, 1912); Bulletins
American Railway Engineering Association; Proceedings American Society
for Testing Materials, etc.; "Mechanical Properties of Wood," Record
(John Wiley & Sons, 1914).

BIBLIOGRAPHY 441

CHAPTER X

Fungi and Fungous Diseases of Woods. — "Outlines of Botany," Leavitt;
"Fungous Diseases of Plants," Duggar; "Diseases of Economic Plants,"
Stevens and Hall; "Flowerless Plants," Bennett (Published Gurney &
Jackson, London); "Fungous Diseases of our Forest Trees," Halstead
(Third Annual Report Pennsylvania Department of Agriculture); "Diseases
of Trees," Hartig; "Diseases of Plants Induced by Cryptogamic Parasites,"
Tubeuf and Smith; "Studies of Some Shade Tree and Timber Destroying
Fungi," Atkinson (Cornell Exper. Sta., Bulletin, No. 193) ; Bulletins American
Railway Engineering Association; " Disease of Taxodium known as Pecki-
ness," von Schrenk (Contribution 14, Shaw School of Botany); "Decay of
Timber," von Schrenk (United States Bureau of Plant Industry, Bulletin
No. 14); "Two Diseases of Red Cedar," von Schrenk (United States Divi-
sion Vegetable Physiology and Pathology, Bulletin No. 21); "Fungous
Diseases of Forest Trees," von Schrenk (United States Department of
Agriculture Yearbook, 1900); "Some Diseases of New England Conifers"
(United States Division Vegetable Physiology and Pathology, Bulletin No.
25); "Diseases of White Ash," von Schrenk (United States Bureau Plant
Industry, Bulletin No. 32); "Diseases of Bull Pine," von Schrenk (United
States Bureau Plant Industry, Bulletin No. 36); "Diseases of Hardy
Ca.talpa," von Schrenk (United States Bureau of Forestry, Bulletin No. 37);
"The Discovery of Cancer in Plants; An Account of Some Experiments by
the United States Department of Agriculture," (The National Geographic
Magazine, Vol. XXIV, No. 1, 1913); "Preservation of Structural Timber,"
Weiss (McGraw-Hill Book Company, 1915); "Diseases of Deciduous Forest
Trees," von Schrenk (United States Bureau of Plant Industry, Bulletin
No. 149, which also contains extensive bibliography), etc.

CHAPTER XI

Failure of Wood because of Fire. Fire Protection. — "On the Compara-
tive Value of Certain Salts for Rendering Fibrous Substances Non-inflam-
mable," Versmann and Oppenheim (British Association for the Advance-
ment of Science, Report of the 29th Meeting held at Aberdeen, September,
1859. Notices and Abstracts, pp. 86-88, 1859); "Rapport sur les pro-
cedes destines a assurer Pinflammabilite des bois," Boudin and Donny
(Annales de 1' Association des Ingenieurs sortis des Ecoles Speciales de
Gand., Belgium, Vol. 2, p. 1, 1887); "Fire Protection of Mills," Woodbury
(John Wiley & Sons, 1895); "Contributions of Chemistry to the Methods of
Preventing and Extinguishing Conflagrations," Norton (Journal of Ameri-
can Chemical Society, Vol. XVII, 1895); Publications of National Board
of Fire Underwriters; Publications National Fire Protection Association;
Files of Insurance Engineering; " Process of Fireproofing Wood for the Wood-
work of Warships," Hexamer (Engineering News, March 23, 1899); "A
Discussion of Recent Developments in the Fireproofing of Wood," Ferrell
(Journal of Franklin Institute, March, 1901); "A New Method of Testing
Fire-resisting Qualities of Fire-proofed Wood," Woolsen (Engineering News,

442 ORGANIC STRUCTURAL MATERIALS

February 20, 1902); " Insurance in Foreign Countries" (United States
Special Consular Report, Vol. 38, Bureau of Manufactures, Department of
Commerce and Labor, Washington, 1905); "A New Investigation of the
Fireproofing of Fabrics," Whipple and Fay (Part of "The Safeguarding
of Life in Theatres," Freeman, Transactions of American Society of Mechan-
ical Engineers, Vol. 27, 1906); "The Safeguarding of Life in Theatres,"
Freeman (Transactions of American Society of Mechanical Engineers, Vol.
27, 1906); "Waste of our National Resources by Fire," Baker (Proceedings
of Meeting called jointly by the American Society of Civil Engineers, the
American Institute of Mining Engineers, the American Society of Mechan-
ical Engineers, and the American Institute of Electrical Engineers, published
in pamphlet, 1909); "The Fire-resistive Properties of Various Building
Materials," Humphrey (United States Geological Survey, Bulletin No. 370,
1909); "The Fire Tax and Waste of Structural Materials in the United
States," Wilson and Cochrane (United States Geological Survey, Bulletin
No. 418, 1910); "The Enormous Fire Waste of the United States," Cochrane
(Scientific American, June 15, 1912); "Fire Prevention and Fire Protec-
tion," Freitag (John Wiley & Sons, 1912); "The Modern Factory," Price
(John Wiley & Sons, 1914) ; "Tests on Inflammability of Untreated Wood and
of Wood Treated with Fire-retarding Compounds," Prince (Report on Uses
of Wood, National Fire Protection Association, 1915).

CHAPTER XII

Marine and Terrestrial Woodborers. — "Marine Woodborers," Snow
(Transactions of the American Society of Civil Engineers, Vol. XI, 1898);
Sigerfoos (Circular, Johns Hopkins University, June, 1896); Harriet
Richardson (Biological Society, Washington, May, 1897); "Insect Life,"
Comstock (Appleton); "Guide to the Study of Insects," Packard (Holt,
Ninth Edition); The Fifth Report of the United States Entomological
Commission; "Insects Affecting Park and Woodland Trees," Felt (New
York State Museum, 1906); "The White Ant," Marlatt (United States
Division of Entomology, Circular No. 50, New Series); "The Insect Book,"
Howard (Doubleday, Page & Company, 1910); "Insect Injuries to Forest
Products," Hopkins (United States Bureau of Entomology, Circular No.
128, 1910); "Report on the Field Work Against the Gypsy Moth and the
Brown-tail Moth," Rogers and Burgess (United States Bureau of Ento-
mology, Bulletin No. 87, 1910); "Some Insects Injurious to Forests/'
Hopkins and Webb (United States Bureau of Entomology, Bulletin No. 58,
1910); "A List of Works on North American Entomology," Banks (United
States Bureau of Entomology, Bulletin No. 81, 1910); "Injurious Insects
and How to Recognize and Control Them," O'Kane (The Macmillan Com-
pany); "List of Publications Relating to Forest Insects," Hopkins and
Others (United States Bureau of Entomology, Bulletin No. 58, pp. 96-101,
1910); "Practical Entomology for Schools," Sanderson and Pearirs (John
Wiley & Sons, 1917).

BIBLIOGRAPHY 443

CHAPTER XIII

Wood Seasoning. — "Timber," Roth (United States Division of Forestry,
Bulletin No. 10, 1895); "Seasoning of Timber," von Schrenk (United States
Bureau of Forestry, Bulletin No. 41, 1903); " Kiln-drying Hardwood Lum-
ber," Dunlap (United States Forest Service, Circular No. 48, 1906); "Prin-
ciples of Drying Lumber at Atmospheric Pressure," Tiemann (United States
Forest Service, Bulletin No. 104, 1912); "Preservation of Structural Tim-
ber," Weiss (McGraw-Hill Book Company, 1915); also see catalogues of
the B. F. Sturtevant Company, the Morton Dry Kiln Company, the Stand-
ard Dry Kiln Company, the American Blower Company, etc. "The
Theory of Drying, etc." Tieman (United States Department of Agricul-
ture, Bulletin No. 509, March 17, 1917).

CHAPTER XIV

Wood Antiseptics : Their Application Within Woods. — " Fractional Dis-
tillation of Coal-tar Creosote," Dean and Bateman (United States Forest
Service, Circular No. 80); "Quantity and Character of Creosote in Well-
preserved Timbers," Alleman (United States Forest Service, Circular No. 98) ;
"The Analysis and Grading of Creosotes" (United States Forest Service,
Circular No. 112); "Volatilization of Various Fractions of Creosote after
their Injection into Wood," Teesdale (United States Forest Service, Cir-
cular No. 188); "Modification of the Sulphonation Test for Creosote,"
Bateman (United States Forest Service, Circular No. 191); "Wood Preserva-
tion," Flad (United States Forest Service, Bulletin No. 1, 1887); "Causes
Underlying the Limited Production of Creosote in the United States"
(Forestry and Irrigation, October, 1906, pp. 482-484); "Decay of Timber,"
von Schrenk (United States Bureau of Plant Industry, Bulletin No. 14);
"Recent Progress in Timber Preservation," von Schrenk (United States
Department of Agriculture, Yearbook, 1903); "Coal-tar and Ammonia,"
Lunge; "Handbook of Timber Preservation," Samuel M. Rowe (Author's
Edition, 1900); "The Preservation of Structural Timber," Weiss (McGraw-
Hill Book Company, 1915); "Antiseptic Treatment of Timber," Boulton
(Proceedings Institution of Civil Engineers, London, 1884); "The Preserva-
tion of Timber," Report of Committee (Transactions American Society
of Civil Engineers, 1885); "Preservation of Railroad Ties," Curtis (Trans-
actions American Society of Civil Engineers, Vol. XLII, 1899); "Proposed
Method of Preservation of Timber with Discussion," Kummer (Transac-
tions American Society of Civil Engineers, Vol. XLIV, 1900); "Preserva-
tion of Railway Ties in Europe," Chanute (Transactions American Society
of Civil Engineers, Vol. XLV, 1901); "Timber Tests and Discussions"
(Transactions American Society of Civil Engineers, Vol. LI, 1903); "The
Inspection of Treatment for the Protection of Timber by the Injection of
Creosote Oil," Stanford (Transactions American Society of Civil Engineers,
Vol. LVI, 1905); Manual, 1911 and other publications of the American
Railway Engineering Association; Specifications American Telephone and
Telegraph Company; Proc. American Wood Preservers Association; Proc.

444 ORGANIC STRUCTURAL MATERIALS

American Society of Municipal Improvements; Files Engineering News,
Engineering Record, Municipal Engineering, etc. Assistance was received
from the Eppinger & Russell Company, Mr. H. M. Mason, Jr. of that
Company, Mr. John S. Crandell of the Barrett Manufacturing Company,
and others.

CHAPTER XV

Paints, Varnishes and Other Coatings: Their Application to Woods. —
"Painters' Colours, Oils, and Varnishes," Hurst (London, 1896); "Drying
Oils," Andes (Scott, Greenwood & Sons, London); "Preparation and Uses
of White Paints," Fleury (Scott, Greenwood & Sons, London); "White Lead
and Zinc Paints," Petit (Scott, Greenwood & Sons, London, 1907); "Letters
to a Painter," Ostwald (Ginn & Company, Boston, 1907); "Analysis of
Mixed Paints," Holley & Ladd (John Wiley & Sons, 1908); "Lead and Zinc
Pigments," Holley (John Wiley & Sons, 1909); "Linseed Oil," Ennis (Van
Nostrand, 1910); "Chemistry of Paints," Friend (Longmans, Green & Com-
pany, 1910); "Materials of the Painters' Craft," Laurie (Foulis, London and
Edinburgh, 1910); "White Paints and Painting Materials," Scott (Modern
Painter, Chicago, 1910); "Manufacture of Varnishes," Mclntosh (Scott,
Greenwood & Sons, London, 1911); "Materials for Permanent Painting,"
Toch (Van Nostrand, 1911); "Paint Technology and Tests," Gardner
(McGraw-Hill Book Company, December, 1911); "The Analysis of Paints
and Painting Materials," Gardner and Schaeffer (McGraw-Hill Book Com-
pany); "German and American Varnish-Making," Bottler and Sabin (John
Wiley & Sons, 1912); "Technology of Paint and Varnish," Sabin (John
Wiley & Sons, 1904 and 1917); "The China Wood Oil Tree," Fairchild
(United States Bureau of Plant Industry, Circular No. 108); "Index to
Patents, Technology, and Bibliography of China Wood Oil (Tung Oil),"
George H. Stevens and J. Warren Armitage (Published by Authors at
Irvington and Newark, New Jersey, 1914); Files of Painters' Magazine,
Oil and Color Trades Journal, Drugs, Oils, and Paints; Proceedings of
the Paint and Varnish Society (London), Farbenzeitung (Berlin), Le Revue
de Chimie Industrielle (Paris), Engineering News, Engineering Record,
Railway Gazette, Transactions American Society for Testing Materials,
Red Lead and How to Us;> It, Sabin (Author's edition, 1917), Journal Indus-
trial and Engineering Chemistry (American Chemical Society) . Assistance
was received from the Sherwin-Williams Company, the F. W. DeVoe and
C. T. Raynolds Company, the Dixon and the Detroit Graphite Companies,
the Heath and Milligan Manufacturing Company, etc.

CHAPTER XVI

Adhesives: Cattle Glues, Fish Glues. — "Glue, Gelatine, Isinglass, Ce-
ments, and Pastes," Dawidowsky (Sampson Low, Marston, Searle &
Rivington, London, 1884); "Glue and Glue Testing," Samuel Rideal (Scott,
Greenwood & Sons, London, 1900); "Glues and Gelatine," Fernbach (Van
Nostrand Company, 1907); Files of Scientific American, Woodcraft, etc.,
etc. Assistance was received from Messrs. Armour & Company, the Ameri-

BIBLIOGRAPHY 445

can Glue Company, the Russia Cement Company, the Studebaker Corpora-
tion, Schmitt Brothers, The Flint & Homer Company, and other manu-
facturers and users of glue.

CHAPTER XVII

Indiarubber: Its Sources, Properties, and Uses. — "Crude Rubber and
Compounding Ingredients," Pearson (Indiarubber Publishing Company,
New York, 1909); Files of Indiarubber World, Journal of Society of
Chemical Industry; "The Culture of the Central American Rubber Tree,"
Cook (United States Bureau of Plant Industry Bulletin No. 49); "Rubber
Cultivation for Porto Rico," Cook (United States Division of Botany,
Circular No. 28); "Indiarubber" (Special Consular Reports, United States
Government Printing Office, 1892); "Guayule, A Rubber Plant of the
Chihuahuan Desert." Lloyd (Carnegie Institution, Bulletin No. 129);
"Indiarubber and Gutta Percha," Seeligmann, Torrilhon and Falconnet
(Scott, Greenwood & Company, London, 1910); "Rubber," Schidrowitz
(Methune & Company, London, 1911) ; " Der Kautschuk und Seine Priifung,"
Hinrichsen and Memmler (Leipzig, Hirsel 1910); "Synthetic Caoutchouc,
A Review Compiled from the Literature," Barrows (The Chemical Engi-
neer, September, 1911, p. 355); "Production and Polymerization of Butad-
iene, Isoprene and their Homologues," W. H. Perkin, Jr. (Journal Society
Chemical Industry, Vol. 31, p. 616, 1912); "Les Produits pour le Fabrica-
tion du Caoutchouc Synthetique," Ditmar ("Le Caoutchouc et la Gutta
Percha," Paris, Vol. IX, p. 6458, 1912); "Les Caoutchoucs Artificiels,"
L. Ventou-Duclaux (Dunot and Pinat, Paris, 1912); "Die Synthese des
Kautschuks," Ditmar (Theo. Steinkopff, Dresden and Leipzig, 1912);
"The Business Aspect of Synthetic Rubber," Hinrichsen (Scientific American,
August 3, 1912, p. 99); "Chemistry of the Rubber Industry," Potts (Con-
stable and Company, London, 1912); "Natural and Synthetic Rubber,"
F. M. Perkin (Journal Royal Society Arts, London, Vol. 61, p. 86, 1913);
"Review of Pioneer Work on Synthesis of Rubber," Pond (Journal Ameri-
can Chemical Society, January, 1914, p. 165); "The Chemistry of Rubber,"
Porritt (D. Van Nostrand Company, New York, 1915). Assistance was
received from the Birmingham Iron Foundry, Mr. Thomas A. Cashman,
Dr. Earl F. Farnau of New York University, and others.

INDEX

PAGE
269

PAGE Algaroba 168

Abies 65, 72 Allardyce Process (Wood Pres-

balsamea 72, 73, 169 ervation 371

concolor . 76 Alligatorwood 188

grandis 72, 74 Amber . 385, 386

lowiana 76 Amber, black 386

magnified 72, 75 American Railway Eng. Assn. :

nobilis 72, 77 Spec, for Creosote . . 344, 345, 346

taxifolia... 70 American Telephone & Tele-

Abietene 60 graph Co. :

Abrasion 241, 256 Spec, for Application of Creo-

Resistance to 241 sote, 358, 359, 360, 365,

Acacia 166 366, 367, 368, 370

False 166 Spec, for Creosote 346, 347

Three-thorned 167 Spec, for Open Tank Process 358,

Acer 133 359

dasycarpum 135 Ammonium phosphate (fire re-

macrophyllum 137 tardant) .... 282, 283, 284

negundo 138 Ancona Auvergne 141

pseudo-platanus 133, 156 Angiosperms 4, 102, 247

rubrum 136 Animal Life, Woods Destroyed

saccharinum 134,135,272 by 225, 300-325, 340

saccharum 40, 133, 134, 246 Anime 386

Adhesives, 159, 206, 208, 337, 403, Annual Deposit (see Annual

404, 405, 406, 407, 408, Rings, Bands or Layers).

409, 410, 411, 412, 413, 414, Annual Rings, Bands or Layers, 5, 6,

415, 416, 417, 418, 419, 420 10, 11, 29, 30, 34, 35, 36, 37,

Aesculus 183 46, 102, 260

calif ornica 183, 185 Ant, Black Carpenter 323

flava 185 White 321

glabra 183, 184 Antiseptic Treatment of Wood, 322,

hippocastanum 183,184 327,328,329,330,331,335,

octandra 183, 185 336, 337, 353, 354, 355, 356,

Agathis australis 63 357,358,359,360,361,362,

Age, Woods Destroyed by. 266, 267 363, 364, 365, 366, 367, 368,

Ailanthus 172 370, 371, 372, 373, 374

Ailanthus glandulosa 172 Antiseptics, Wood, 262, 265, 335, 338,

Alburnum 37 339, 340, 341, 342, 343, 344,

Alcohol. . . . 381, 387, 424, 425, 426 345, 346, 347, 348, 349, 350,

Aleuritesfordii 214, 380 351, 352, 353

447

448

INDEX

PAGE

Apple 92, 126, 127, 213

American Crab 127

Narrowleaf Crab 127

Oregon Crab .. . 127

Sweet Crab 127

Apple-tree 116, 127

Osage 204

Arborvitse 85, 86, 89, 90

Giant 90

Arbutus 195

menziesii 195, 197

texana 197

xalapensis 197

Arctostaphylos 197

glauca 197

pungens 197

tomentosa. 197

Arundinaria 231

Arundo 231

Asbestos 284, 285, 401

Asbestos Paints 284, 285, 401

Ash, 3, 30, 38, 120, 121, 122, 125,
126, 275

American 121

Black 120,122,124,138

Blue 123, 125,248

Brown 122,124

Cane 121

Green 120, 125,248

Hoop 124

(Mineral) 17, 236, 281

Mountain 126

Oregon 126,248

Prickly 126

Pumpkin 248

Red 122

River 122

Second Growth 120

Stinking 138

Sugar 138

Swamp 124,125

Water 124,125,138

White 120, 121, 125, 248, 273

Yellow 126

Aspen 169

Large American 172

Largetooth 172, 248

Quaking 172

Associated Compounds 26, 235

PAGE

Attalea excelsa 426

Attempts to Prevent Wood from

Burning 282

Automatic Sprinklers, 289, 295, 297,

298
Avenarius Carbolineum, 352, 388,

389

B

Bacteria 13, 42, 268, 269

Balluck 218

Balm 174

Balm of Gilead 73, 169, 174

Balsa 214,246

Balsam, 68, 73, 76, 169, 174, 275

Canada 72, 73

He 66

Poplar 169, 174

White 76

Balsam-tree 76

Bamboo, 4, 7, 165, 224, 225, 230, 232

Bambusa 230, 231

vulgaris 232

Bands, Rings or Layers, Annual, 5, 6,

10, 11,29,30,34,35,36,102

Banded Trunks and Woods, 5, 6, 9, 29,

30, 34, 43, 44, 102, 169, 224

Barium Sulphate (Pigment) 382, 383

Bark 30,38,39,176,224

Fungous Diseases of 272

Green 38

Inner or Fibrous 38

Barnacles 314

Bass 170

Basswood. 169, 170, 176, 248, 275

Common 176

White 176

Yellow 176

Bast 38, 176

Fibers 38, 176

Hard 38

Soft 38

Bastard Cut 40

Bay, Rose 195

Bay-tree 196

California 196

Bayonet, Spanish 228

Bay wood 208

INDEX

449

PAGE

Bead Tree 214

Beantree 181

Bebeeru 201

Bee, Carpenter 323

Beech, 19, 30, 152, 153, 248, 275, 375

Blue 154,248

European 152

North American 152

Red 153

Ridge 153

Water 154,157

White 153

Beetles 56, 64, 318, 319, 320

Attacks by 318,319

Colorado Potato 318

Beetree 170,176

Benzine 381

Benzol 381

Bethell Process (Wood Preser-
vation) % . 363, 370, 371

Betula 159

alba 159

lenta 159,164,202

lutea 159, 163

nigra 162

papyrifera 159, 160, 161

populifolia 160

Biberine 200

Bibiru 201

Big-bud 147

Bigtree 77, 101

Birch, 43, 155, 159, 162, 248, 275,
375

Black 162,164

Blue 162

Canoe 161

Cherry 164

European 159

Gray 160, 163

Large White 161

Mahogany 164

Oldfield 160

Paper 159, 160, 161

Poplar-leaved 160

Poverty 160

Red 162

River 162, 164

Silver 161,163

Small White.. . 160

PAGE

Birch, Swamp 163

Sweet 159,164,202

Water 162

White 160,161

Yellow 159,163

Bismarck Brown, Pigment 388

Bitternut 146

Black Carpenter Ant 323

Blackjack 248

Black Scale 214

Blackwood 215

Bled Woods 46, 47

Blisted 188

Blister Rust 48, 50

Bloodwood 215

Blowdown (see Windfall} . . 65, 121
Bluing in Wood. ... 42, 56, 251, 268

Boards 40

Bodark 204

Bodock 204

Boiling Process (Wood Preser-
vation) 372

Boisd'Arc 202,204

Bois puant 157, 180

Boleau 161

Bookworms 320

Bordered Pits 18, 20

Borers, Stone 314

Wood (see Marine and Land

Woodborers) .

Boring Gribble, 310, 311, 312, 313
Bot in Wood (see Decay] ... 42, 268
Botanical and Common Names . 2
Boucherie Process (Wood Pres-
ervation) 372, 373

Bow-wood 204

Box 62, 191,216

Dogwood False 193

Boxelder 34,133,138

Boxwood 191, 193, 197

American 191

New England 193

Branches, System of 8, 9

Brashwood. 42, 267

Broadleaf Trees and Woods, 4, 5, 6,
29, 43, 44, 102, 103, 169, 333
Brown, Bismarck (Pigment) . . . 388
Brush Method (Wood Preserva-
tion) . . 354

450

INDEX

PAGE

Buckeye 183, 185

Big 185

California 185

Fetid 184

Large 185

Ohio 184

Stinking 184

Sweet 185

Yellow 185,248

Bullnut 147

Burl 124, 139

Burnett Process (Wood Preser-
vation) 368, 369, 371

Burning Woods 281, 236

Burr (see Burl).

Butadiene 435

Butterflies and Moths 320

Summary 321

Butternut, 139, 140, 141, 143, 210,
248

Buttonball 156, 157, 158

Buttonball-tree 157, 158

Button wood -. . . 157, 158

Buxus 191

sempervirens 191

Cabbage Tree 227

Cajeput 196

Calamus rudentum 232

Calathaea 426

Calcium Carbonate in Wood. . 22

Calcium in Wood 22

Calcium Oxalate in Wood 22

Calico Bush 195

Callitris quadrivalvis 387 i

Cambium, 10, 11, 22, 34, 39, 224, 228 j

Cork 39

Layer 10, 11

Camphor Tree 198

Camponotus herculeanus penn-

sylvanicus 323

Canada Balsam 72, 73

Canal, Resin 23, 25, 26, 28

Canals, Primary 26

Secondary 26

Canker in Wood 42

Canoewood.. . 171

PAGE

Caoutchouc (see Indiarubber},
423, 432

Carbolic Acid 342

Carbolineum 352, 388, 389

Avenarius 352, 388, 389

Carbon 9, 234, 236, 281, 288

Dioxide 9, 288

in Wood 9, 234,236, 288

Pigment 384

Tetrachloride 288

Card Process (Wood Preser-
vation) 371

Car Painting 400

Pullman Company Specifica-
tion 400

Care of Structures 298, 299

Carpenter Ant 32%

Bee 323

Worm 321

Carpinus 154

caroliniana 154

Carya 145,146,147, 148

alba 145,246

olivceformis 148

porcina 146

tomentosa 147

Casein 389

Cassia Bark 198

Castanea 149,273

dentata 108, 150, 151

pumila 149, 151

vesca var. americana 150

vulgaris 149

vulgaris var. americana 150

Castanopsis chrysophylla . . . 149, 151

Castilla alba 427

elastica 213, 427

Catalpa, 30, 179, 180, 181, 207, 246,.
273, 275

Common 179

Hardy 179, 180, 181, 248

Western 180

Catalpa 179

bignonioides 181

catalpa 179, 181

speciosa 179, 180, 181, 246

Catawba 181

Tree 181

Caterpillars 320

INDEX

451

PAGE

Cattle Glues,

Application of 159, 408

Manufacture of 404, 405

Properties of, 405, 406, 407, 408,
409, 410, 411, 417, 418,
419, 420

Protection of 410

Sources of. 404

Testing of 417, 418, 419, 420

Cedar, 3, 43, 85, 87, 88, 89, 90, 92, 95,
207, 209, 386

Atlantic Red 89

Australian Red 209

Bastard 94,214

California Post 94

California White 94

Canoe 86, 90

Cuban 209

Eastern 85

Giant 72,90

Giant Red 90

Incense 86, 87, 94, 97, 272

Lebanon 85

Mexican 209

Northern White 275

Oil 380

Oregon 92

Pacific Red 90

Pencil 87

Port Orford 86,92

Post 91,94

Red, 85, 86, 87, 90, 94, 97, 209

Southern 85

Southern Red 85

White 275

Spanish 86,207,209

Swamp 91

Toon . 209

Western 85,88,90

Western Red 88, 275

White, 85, 86, 89, 91, 92, 94,

214
Yellow 86,88,93

Cedrela 206,207

australis 209

odorata 207, 209

Blanco 209

toona Roxburgh 209

Cedrus . . 85

PAGE

Cells, Companion 38

Epithelium 25, 26

Parenchyma 38, 39

Pith-ray 19

Wood (see Wood Elements).
Cell Structures (see Wood Ele-
ments).

Cellular Structure of Wood, 17, 32
Cellulose. . 9, 17, 234, 235, 270, 281

Celluloid 434

Celtis occidentalis 152

Cendre 87

Census Experiments upon

Woods 33,257,261

Central Office System 299

Ceraostomella pilifera (fungus) . . 272

Cercocarpus ledifolius 207

parvifolius 207

parvifolius betuloides 207

Chamcecyparis 85, 95

lawsoniana 86, 92

nootkatensis 93

nutkcensis 93

nutkatensis 86

thyoides 86, 91

Charring (Wood Preservation) 373,

401

Checks in Wood (see Defects in
Wood).

Chelura 313,314

Excavations 313

Field of Attack 314

Method of Attack 313

Physiology of 313

Size of Borings 314

Chelura terebrans 313

Chemical,

Composition of India-rubber, 431,

432, 433, 434

Composition of Wood, 9, 13, 26,
37, 38, 39, 233, 234, 235,
237, 281

Compounds Applied within
Woods (See Preserva-
tion of Wood).
Elements in Wood, 13, 26, 234, 281

Fire Extinguishers 289, 290

Chemicals, Processes to Introduce

within Woods 335, 353-375

452

INDEX

PAGE

Chene etoile 109

Vert 116

Cherry 30,159,202

Black 205,248

Choke 205

Red 248

Rum 205

Whiskey 205

Wild 202,205

Wild Black 202,205

Chestnut, 30, 108, 149, 150, 151, 273,
275

Blight 149, 150, 2Y2, 273

Evergreen 149

North American 149

China 214

China-berry 214

China Wood Oil 214, 380

China Wood Oil Tree 214, 380

Chinquapin 149, 151

California 149

Common 149

Goldenleaf 149

Western 149

Chlorophyll 9, 13, 38, 235, 268

Chloroxylon 215

swietenia 215

Chrome green Pigment 382

yellow Pigment 382

Cigar Tree 180, 181

Indian 181

Cinnamomum 198

camphora 198

cassia 198

zeylanicum 198

Cinnamon Tree 198

Citronella 380

Citrus aurantium 127

trifoliata 127

Cladrastis tinctoria 126

Clam, Long 301

Razor 301

Softshelled 301

Classifications, Fundamental, 1, 4, 5,
6

Coach Painting 400

Coatings for Woods . 377, 400

Coefficient of Elasticity, 33, 238, 239,
261

PAGE

Coefficient of Rupture. .33, 239, 261

Coffee 152

Coffeebean 152

Coffeebean-tree . 152

Coffeenut 152

Coleoptera 319

Colophony. 388

Color Defined 251

Color of Wood 251

Coloring Matter in Wood ... 17, 251
Common and Botanical Names . 2

Companion Cells 38

Comparison, Woods with Stones

and Metals xvii, 1, 2, 255
Compounds Associated with

Woods 26

Associated with Wood-ele-
ments 17,26

Inorganic 26, 236

Organic 26, 234

Conductivity (Defined) 248

of Wood 237,248

Cone-bearers (see Conifers).

Cones (see Conifers) 44

Confederate Pintree 167

Conflagrations Influenced by

Wood 277,280,294

Coniferae (see Conifers).
Coniferous Trees (see Conifers)

Woods (see Conifers).
Conifers, 4, 5, 6, 20, 30, 34, 43, 44,
102

Conservation xvii

Consumption of Wood 1

Convolvulus scoparius 214

Copal 386

Manila 386

Sierra Leone 386

South American 386

Zanzibar 386

Copper Sulphate, Effect upon

Wood . 337,338, 374

Cork 246

Cork Cambium 39

Corkwood, Missouri 246

Corky Layer 39

Cornel 193

Flowering 193

Cornus.. . 191

INDEX

453

PAGE

Cornus, florida 191, 193

Cortex 38,39,224

Cossus ligniperda 321

Cotonier 157

Cotton Tree 173

Cottonwood, 30, 169, 173, 174, 275,
375

Balm 174

Balsam 174

Big 173

Black 175,248

Broadleaved 173

Yellow 173

Cotton Wool 234

Cotyledon 4, 9

Cracks in Wood, (see Defects in

Wood) 40

Creoaire Process (Wood Preser-
vation) 374

Creo-resinate Process (Wood

Preservation 372

Creosote, 281, 317, 318, 322, 337, 339,
340, 341, 342, 343, 344, 345,
346, 347, 348, 349, 350, 351,
375, 376

Analysis of 344, 348, 349, 350

Constituents of 341, 342

Distribution of 351

Effects upon Wood 340, 341

Mixed 343

Required Quantities of 351

Sources of • 341

Specifications, 344, 345, 346, 347,
348, 349, 350

Cresylic Acid 342

Cross-surfaces of Wood 39

Croton lacciferus 387

Crude Sap 11,235

Cryptogams 269

Cucumber 175

Cucumber-tree 169, 171, 175

Cupressus 95

macrocarpa 95

Cup Shakes in Wood (see De-
fects in Wood) 41

Cut, Bastard 40

Quartered 39, 40, 334

Tangential 24,40

Cycadaceoe 4

PAGE

Cylinders, Use of 360

Cynoxylonfloridum 193

Cypress, 3, 85, 86, 87, 94, 95, 97, 246,
272, 275

Alaska 93

Alaska Ground 93

American ... 96

Bald. 96,97

Black 96, 97

Common 95

Deciduous 97

Evergreen 95

Lawson 92

Monterey 95

Nootka 93

Nootka Sound 93

Red 96,97

Sitka 93

Southern 97

Swamp 86, 97

White.. 96,97

Yellow 93,96

Cyst 25

D

Doedalea vorax (fungus) . 96, 97, 272

Dagger, Spanish 228

Dalbergia nigra 214

sissoo 213

Dammara 62, 387

australis 63, 221, 387

orientalis 387

Date, Plum 203

Wild 226

Deal 59

White 64

Decay in Wood, 42, 96, 265, 266, 268,
269, 270, 271, 272, 273,
274, 275, 276
Deciduous Trees and Woods, 4, 6,

43, 103
Defects in Woods . . 40, 41, 42, 333

Deformation in Woods 237

Dendrocalamus 231

Dendroctonus piceaperda 64

ponderosa 56

Density of Woods, 237, 244, 246, 247

Density Rule 46, 260

Density Test 46, 245, 260

454

INDEX

PAGE

Deposit, Annual, (see Annual
Ring Bands or Layers).

Springwood 30, 31, 35, 36

Summer-wood. . . 30, 31, 35, 36
Destruction Woods, by Age, 266, 267

by Ants 321, 323, 324

by Bees 323

by Beetles 319, 320

by Chelura 313

by Decay (see Decay in
Woods').

by Exposure 267

by Fire, 277, 280, 281, 282, 283,

284, 285, 286

by Limnoria. . . 310, 311, 312, 313
b y Miscellaneous Wood-

borers 314

by Moths and Butterflies, 320, 321

by Shipworms, 225, 300, 307, 308,

309, 310, 315, 316, 317, 318

by Termites 321, 322, 323

by Use 267

Destructive Temperatures 293

Diaporthe parasitica (fungus), 149,

150, 272, 273
Dicotyledons, 4, 5, 6, 30, 34, 43, 102,

169
Dicotyledonous Trees and

Woods (see Dicotyledons') .

Diffuse-porous Woods 30, 31

Diospyros 202

chloroxylon 202

ebenaster 202

ebenum 202, 246

mespiliformis 202

virginiana 202,203

Dipping Method (Wood Preser-
vation) 354

Direct Physiological Properties . 233
Disease, Bark. . . . 149, 150, 272, 273

Black Scale 214

Blister Rust 48,50

Chestnut Bark, 149, 150, 272, 273

Foliage... 272

Roots 272

Trunks and Trees. . 268, 271, 272
Woods (see Decay in Woods).

Distortion of Wood 264

Distribution of Species 16

PAGE

Dogwood 191, 193

Flowering 191, 193, 248

Poison : 193

Doors, Fireproof, 284, 285, 295, 296,
402

Dote in Wood 42, 268

Douglas Fir 25, 246

Douglas Tree 71

Dragon-tree 224

Driers 379,380

Japan 380

Dry Rot in Wood 42, 268, 274

Duct 21

Resin (Wood Element), 23, 25,

26, 28
Durability of Wood, 266, 274, 275,

276
Duramen 37

E

Ebenaceoe 202

Ebonite 434

Ebony 202,246

Green 202

Madagascar 202

Mexican 202

Edge-grained Woods 40

Edging 40

Elaborated Sap 11, 37, 235

Elasticity (Denned) 240

Modulus of 33, 238, 239, 261

of Wood 18,33,237,240

Electrical Conductivity of

Wood 248

Elements, Chemical, in Wood, 13, 17,

26, 234, 281

Wood (Cell-Structures), 17, 18, 19,
20, 21, 22, 23, 24, 25, 26, 27,
28,29,30,31,32,34,38,39,
44, 102, 224, 225, 237, 247,
248, 249, 252
Elm, 3, 43, 92, 102, 128, 129, 132, 248

American 129

Cliff 130

Cork 130,132

Corky 132

False 152

Hickory 130

Moose.. . 131

INDEX

455

PAGE

Elm, Mountain 132

Red 131,132

Redwooded 131

Rock 130, 131

Slippery 129

Small-leaved 132

Wahoo 132

Water 129

White 129

Wing 132

Winged 132

Witch 132

Empty Cell Processes (Wood

Preservation), 351, 362, 363,
369

Enamelled Paints 378, 398

Encena 117

Endogen 6, 7, 224

Endothia gyrosa (fungus), 149, 150,

272, 273
Endothia gyrosa var. parasitica

(fungus), 149, 150, 272, 273

Entandrophragma candollei 206

Enzyme 270

Epidermis 39

Epithelium Cells 25

Eppinger & Russell Specification, 364

Erosion (Soil) 14, 15

Eucalypt, Giant 223

Eucalyptus, 26, 216, 217, 218, 219,
220, 221, 222, 223, 248

Blue Gum 248

Eucalyptus 216

amygdalina 216, 223

colossea 221

corynocalyx 223

diversicolor 216, 221

globulus 216,217,218

gomphocephala 216, 222

leucoxylon 246

macrorrhyncha 223

marginata 216, 220

resinifera 223

rostrata 216, 219

viminalis 223

Euphorbiacece 214

Evergreen Trees and Woods (see

also Coniferous Trees and
Woods) ... 4 6, 43, 44, 81

PAGE

Examinations, Microscopical, 30, 31,
247

Exogen 5, 6

Experiments (see Tests).

Physical, Woods, 33, 243, 251, 252,

255, 256, 257, 258, 259, 261

Railroad Spikes 242

Exposure, Woods Destroyed by, 266,
267, 268, 273, 274, 275, 276

External Preservative Treat-
ment of Woods, 266, 273,
274, 282, 284, 285, 286, 315,
316, 317, 324, 334, 377 to
401, 410

Fagus 152

americana 19, 152, 153

atropunicea 153

ferruginea 153

grandifolia 153

sylvatica 152

Families (Defined) 3

Fastenings for Woods 237, 242

Feather-cone 77

Ferns 269

Ferrell Process (Wood Preser-
vation) 374

Fever Tree 218

Fibers, Wood, 18, 19, 20, 22, 25, 30,

102, 247
Wood-parenchyma. ... 19, 22, 24

Fibrous Bark 38

Ficus elastica 213, 427

sycomorus 156

Fig Tree 156

Figures Relating to Physical

Properties of Woods, 33,
257, 258, 259

Fillers, Wood 384, 385, 396, 397

Fir 3,43,64,65,70,72

Balm of Gilead 73

Balsam 72,73,76

California Red 75

California White 76

Colorado White 76

Common Balsam 73

Concolor White 76

Dantzic . . 59

456

INDEX

PAGE

Fir, Douglas 70, 71, 246, 275

Golden 75

Great Silver 74

Lowland 74

Magnificent 75

Memel 59

Noble 72,77

Noble Red 77

Noble Silver 77

Northern 59

Oregon White 74

Prince Albert's 79

Red 70,71,72,75,77,78

Red-bark 75

Rigi 59

Scots 59

Scottish 59

Silver 72,74,76

Stettin 59

Swedish 59

Tree 73

Western Hemlock 79

Western White 74

White 64,74,76

Yellow 70,71,74

Fire, Apparatus, 280, 287, 288, 289,
290, 291, 292

Burning Woods 236, 281

Coatings 284, 285, 286

Application 284, 286

Extinguishers, Chemical. 289, 290

Sprinklers 297, 298

Extinguishing Materials 288

Losses 278,279,280

Indirect 278

Pails 290,291,292

Protection 280,282,284,292

Retardants 282, 283

Risks 15

Signals 298

To Extinguish 280, 287

Underwriters' Specifications- 297

Woods Destroyed by 277

Fireproof Buildings 294

Doors 284, 285, 295, 296, 402

Materials 294, 295

Paints 284,285,402

Shutters 285,295,296

Windows.. . 296

PAGE

Fireproof ed Woods . . . 282, 286, 402
Fires in Buildings, Prevention . . 294

First-growth Woods 120

Fish Glues, Application of 414

Manufacture of 411, 412

Properties of 413

Sources of 411

Fistulse 21

Flax 38, 379

Flax Fiber (see Cellulose) 234

Flea (Wood flea) 310

Floods 14

Foliage, Fungous Diseases of ... 272
Forest Service, National, Speci-
fication for Creosote . . 348

Forest Top-soil 13

Forests 13, 14, 15

Influence on Erosion 14, 15

on Rainfall 14, 15

on Streamflow 14, 15

Value of 13

Forestry 15

Formalin 408, 410

Forms of Trees 12, 13

Fossil Resin 62, 386, 387

Fraxinus 120

americana 120, 121

lanceolata 120, 125

nigra 120, 124

oregona 126

pennsylvanica 122, 125

pennsylvanica var. lanceolata. . 125

pubescens 122

quadrangulata 123

sambucifolia 124

viridis 125

Fresh Water Wood-borers 314

Frost Shakes in Wood 41, 333

Full Cell Processes, Wood Pres-
ervation, 351, 361, 362, 363,
368, 369, 371

Fundamental Classifications, 1, 4, 5, 6
Fungi, 13, 42, 64, 96, 149, 150, 262,
, 263, 268, 269

Bread 269

Fungous Diseases 267, 273

Bark 149, 150, 272, 273

Contagion 276

Foliage.... 272

INDEX

457

PAGE

Fungous Roots 272

Structural Woods 273, 274, 275,

276

Trees and Woods. . . 268, 271, 273
Trees.. . 271

Gallic Acid 104,119

Gelatine 403, 404, 410, 411

Genereso 210

Genus 3, 32

Gleditsia 165

triacanthos 165, 167

Glues, 159, 206, 208, 337, 389, 403,
404, 405, 406, 407, 408, 409,
410,411, 412,413,414,415,
416, 417, 418, 419, 420

Action of 410

Appearance of 408, 413

Application of . .159, 337, 408, 414

Cattle, 403, 404, 405, 406, 407,

408, 413, 417, 418, 419, 420

Failure of 407

Fish. 159, 337, 403, 411, 412, 413,

414, 420
Liquid (see Fish Glues) .

Specifications 408, 409, 417

Tests 417,418,419,420

Uses of 414

Woods, Prepared for 408, 414

Gnetacece 4

Gopher Plum 189

Wood 95,126

Grain of Wood 26, 27, 28, 39

Graphite 384, 434

Greenheart 200, 201, 246, 275

Black 201

Gray 201

Yellow... 201

Gribble 310, 311, 312, 313

Boring 310, 311, 312, 313

Growth, Length 9, 12

Thickness 9

Tree 9,12,32

Guadua 231

Guajac 191

Guajacum 191, 194

arboreum 194

officinale 191, 194

PAGE

Guajacum, sanctum. . . 191, 194, 246
Guayule (Indiarubber), 213, 426, 427
Gum (Excretions), 25, 37, 62, 165,

234,235,385
Gum (Trees), 186, 188, 190, 216, 218,

219, 220, 221, 222, 223
Gum, Black.. . . 19, 76, 187, 190, 248

Blue 216, 217, 218, 248

California Red 186

Cotton 21, 189

Mahogany 220

Manna 223

Red, 102, 141, 186, 187, 188, 216,
219, 223, 248

Sour 187, 189, 190

Star-leaved 188

Sugar 223

Sweet 31, 186, 188

Tree 186, 188,216

Tree, Yellow 190

Tupelo 186, 189, 190

Water 186,248

White 221,222

Gumbo file 199

Gymnocladus dioicus 152

Gymnosperms 4

H

Hackberry 152

Hackmatack 83,84

Hard Bast 38

Hardhack 155

Hardness (Defined) 241

Hardness of Wood, 18, 237, 241, 245

Hardshell 146

Hardwood Mfrs.' Asso. Specif. 42

Trees and Woods 4, 6, 43, 102

Hardwoods 4, 6, 43, 102

Hasselmann Process (Wood

Preservation) 374

Hayford Process (Wood Preser-
vation) 364

; Hazel 186, 188

! Heart Shakes in Wood (see De-
fects in Wood) 41

Heartwood 25, 34, 37, 38, 47, 246,

247, 262, 351

Heat, Conductivity of Wood . . 248
Effect upon Wood, 266, 329, 361

458

INDEX

PAGE

Hedge 204

Hedge-plant 204

Hemlock, 3, 43, 44, 65, 78, 79, 80,
275, 375

Alpine 78

Bastard 70

Black 79

Carolina 80

Eastern 78

Southern 80

Spruce 78, 80

True Black 78

Western 78,79

Hevea brasiliensis 213, 427

Hevea rubber, 213, 422, 424, 425,
427

Heyderia decurrens 94

Hickory, 3, 4, 30, 43, 92, 140, 144,
145, 147, 246

Bitternut 248

Black 146, 147

Broom 146

Brown 146

Common 147

Hard Bark 147

Mocker Nut . . . 147

Nut 147

Nutmeg 248

Pecan 148

Pignut 146

Red 146,147

Scalybark 145

Second-growth 120, 144

Shagbark 145,248

Shellbark 145,248

Switchbud 146

Upland.. 145

White 92, 145, 146, 147

Whiteheart 147

Hicoria 144

alba 147

glabra 146

ovata 145

pecan 148

HogNut 147

Holly 30, 191, 192, 248

American 192

European 191

White.. . 192

PAGE

Honey 167

Pod 168

Shucks 167

Horizontal Wood-structure .... 26

Hornbeam 154, 155

Hop 155

Horse Chestnut 183

American 183

California 185

Humus 13, 14

Husk 38

Hygroscopicity 251

Identification of Trees and

Woods 17,27, 28, 29,

30, 31, 32, 36

Idioblasts 22

Ilex 191

aquifolium 191

opaca 191, 192

Impact Testing Machine 245

Importance of Wood 1

Indian Bean 180, 181

Indian Cigar Tree 811

Indiarubber, 213, 421, 422, 423, 424,
425, 426, 427, 428, 429, 430,

431, 432, 433, 434, 435
Chemical Composition of, 431,

432, 433, 434
Classification Due to Form . . 429

Crude 427,428,433

Fresh 427,428

Grades of 426

Guayule 213,426,427

Latex, 421, 422, 423, 424, 425, 426

Para 213, 423,424,427

Physical Properties of 431

Plantation 428

Preparation of 429, 430, 431

Properties of . . . 431, 432, 433, 434

Pure 423,432

Purification of 429, 430, 431

Reclaimed 427,428

Refined 427,428

Shrub 213,427

Sources of 213,426,427

Synthetic 435

INDEX

459

PAGE

Indiarubber, Uses of 434

Vulcanized 430, 431, 433, 434

Wild 428

Indiarubber Tree 213, 427

Assam 213,427

Central American 427

Hevea .... 213, 422, 424, 425, 427

Indiarubber Vine 427

Ink, Printer's 380

Inlaid Work 191, 192, 416, 417

Inorganic Compounds in Wood, 26,

236

Inorganic and Organic Mate-
rials, Comparison, xvii,
xviii, 233, 234, 236, 237,
255, 281

Insects, 318

Associated with Fungi 271

Hosts ,of Micro-organisms. . . 271
Woodborers, 318, 319, 320, 321,

322, 323, 324, 325
Woods Protected from . '. 324, 325

Inside Growth 6, 7, 9, 224

Internal Preservative treat-
ment of Woods, 266, 282,
283, 284, 317, 322, 334, 335
to 376

Introduction xvii

Ironbark 216, 223, 246

Iron Oxide Pigments 383

Ironwood 154, 155, 168, 194

Isinglass 411

Isoprene 435

Isoptera 321

Japan 380, 381

Jarrah 216,220

Jenicero 210

Joints, Wood and Glue, 410, 411, 414

Joshua-tree 228, 229

Juglans 139

australis 141

calif arnica 140

cinerea 139, 140, 141, 143

insularis 141

nigra 19, 21, 22, 23, 139, 142

regia 139, 141,209

rupestris 140

PAGE

Juniper 83, 85, 87, 88, 91, 94

Bush 87

California 88

Red 87

Western 88

Juniperus 85

barbadensis 85, 86

calif ornica 88

occidentalis 88

scopulorum 85, 86

virginiana 85, 86, 87

K

Kalmia latifolia 195

Kalsomine 389

Karri 216,220,221

Kauri Pine 62, 63, 387

Kauri (Resin) . 62, 63, 385, 387, 388

(Tree) 62, 63, 387

Khaya 206

grandifolia •. 206

senegalensis 206

Kiln Drying of Wood (Wood

Preservation) 327, 328

329, 330, 331, 332, 333, 334

Kilns, Forms of 330, 331, 332

Knots (see Defects), 41, 42, 43, 45,
333

Encased 42

Large 43

Loose 42

Pin 43

Pith 42

Rotten 43

Round 43

Sound 42

Spike 43

Standard 43

Kyan Method (Wood Pre-
servation) 355

Lamella, Middle (Wood Ele-
ments) 18

Land Life, W'oods Destroyed by,

266, 309, 310, 313, 318, 320,
322

460

INDEX

PAGE

Land and Marine Woodborers, 225,
300, 301, 302, 303, 304, 305,
306,307,308,309,310,311,
312, 313, 314, 315, 316, 317,
318, 320, 321, 322, 323, 324,
325

Landolphia dawei 427

heudelotii 427

kirkii 427

owariensis 427

thollonii 427

Larch 70, 77, 81, 82, 83, 84, 96

American 83

Black 83

Eastern 81

European 81,82

Great Western 84

Red 83

Red American 84

Western 81, 84

Larix 81

americana 81, 83, 84

europcea 81, 82

laricina 83

occidentalis 81, 84

Latex (Indiarubber), 421, 422, 423,
424, 425, 426

Laurel 195, 196, 197

Big 195

California 195, 196

Great 193, 195

Madrona 195,197

Mountain 195, 196

Laurelwood 197

Layers, Cambium (see also Cam-
bium} 10, 11

Bands, or Rings, Annual, 5, 6, 10,
11, 29, 30, 34, 35, 36, 39,
46, 102, 260

Corky 39

Concentric 5

Lead, Oxide, Pigment 380

Red, Pigment 383

White, Pigment 378, 382

Leaf -system of Tree 9

Leaves 9

Leguminosce 165

Leitneria floridana 246

Length-growth of Trees 9, 12

PAGE

Lepas antifera 314

Lepidoptera (Insects) 320

Lepisima saccharina (Beetle) . . . 320

Leverwood 155

Libocedrus 85

decurrens 86, 94

Lichens 269

Life, Animal, Woods Destroyed

by 266,300

Light, Influence of 12, 13

Lignin 11, 17, 234, 235, 270, 281

Lignumvitae, 26, 191, 194, 201, 246,
275

Lime 170

Ogeechee 189

Lime Tree, Black 176

Smooth-leaved 176

Limetree 170, 176, 189

Wild 189

Limnoria. . . 310, 311, 312, 313, 340
Effects of Temperature and

Water 311

Excavations 311

Field of Attack 313

Form and Physiology of 310

Methods of Attack 311

Rapidity of Attack 312

Size of Borings 311

Woods Subject to Attack. ... 313

Limnoria lignorum 310

Lin, Black 175

Lind 170

White 176

Linden 170,176

American 176

Linn 176

Linoxyn 379,383

Linseed Oil 379, 380, 383, 389

Liquidambar 186, 188

Liquidambar 186

styraciflua 141, 186, 188

Liriodendron 169

tulipifera 169, 171, 175

Litharge 383,434

Live Oak 105, 116, 118, 246

Locality of Species 16

Locust 165,166,167,246

Black, 30, 165, 166, 167, 248, 275,
375

INDEX

461

PAGE

Locust, Green 166

Honey. . . . 165, 166, 167, 168, 248

Honey Shucks 167

Pea-flower 166

Post 166

Red 166

Sweet. 167

Thorn 167

Thorny 167

White 166

Yellow 166

London, Brighton & South
• Coast Railway Spec.

(Creosote) 364

Long Clam 301

Longshucks 55

Lowry Process (Wood Preser-
vation) 370, 371 j

Lumber (defined) 17

Rolled 41

Lumen 18, 19

Lysiloma sabicu 213

M

Madura aurantiaca 204

Madeira 208

Madrona.... 195, 197

Mexican 197

Madrone 197

Madrone-tree 197

Madrove 197

Magnolia 169, 175, 195, 248

Mountain 175

Magnolia 169, 195

acuminata 169, 175

fcetida 195

Mahogany, 152, 159, 202, 206, 208,
216, 220, 246, 396, 416

African 206,212 |

American 163

Birchleaf 207

Central American 206

East Indian 206

Frontera 206, 208

Honduras 206, 208 !

Mexican 208

Mountain 164, 207

PAGE

Mahogany, Philippine 206

Primavera 207

Red 206,223

Spanish 206,208

Valley 207

White 143,207,210

Maintenance of Structures 298

Mammoth Tree 101

Manzanita 197

Maple, 3, 4, 30, 43, 102, 133, 137,
156, 246, 248, 375

Ash-leaved 138

Birdseye 40, 133

Black 134

Blister 133

Broad-leaved 137

Curly 40, 133

Cut-leaved 138

European 133

Hard 40,133,134

Negundo 138

Oregon 137

Red 136

Red River 138

River.. 135

Rock 134

Silver 129, 135

Soft 133,135,136,272

Sugar 133,134

Swamp 135, 136

Three-leaved 138

Water 135, 136

White 135, 136, 137

Marine and Land Wood-borers, 225,
300, 301, 302, 303, 304, 305,
306, 307, 308, 309, 310, 311,
312, 313, 314, 315, 316, 317,
318, 320, 321, 322, 323, 324,
325, 340
Marine Life, Woods Destroyed

by, 225, 266, 309, 310, 315,
322

Woods Protected from, 315, 316,
317, 318, 320, 322, 323, 324,
325
Marsonia ochroleuca (fungus) . . 272

Mastic 388

Materials, Associated with

Wood, 235

462

INDEX

PAGE

Materials, Chemical Composi-
tion of Wood, 9, 13, 26, 37,
38, 39, 233, 234, 235, 237,
281

Fireproofing 294

Fire retardants 282, 283

Inorganic, 17, 233, 234, 236, 237,

255, 281

Organic, 9, 11, 19, 37, 234, 235, 236

Physical Properties of, 33, ' 237,

238, 239, 240, 241, 242, 243,

244, 245, 246, 247, 248, 249,

250, 251, 252, 255, 256, 257,

258, 259, 260, 261

Physiological Properties of. . .233

Wood Preservatives, 337, 338,

339, 340, 341, 342, 343, 344,

345, 346, 347, 348, 349, 350,

351, 352

Measurements, Physical Proper-
ties .... 251, 252, 255, 256

Medulla , 37

Medullary Ray 24, 40

Meliacea 207

Melia azedarach 214

Mercury Bichloride 337, 338

Merisier 163

Rouge 163

Mesquite 165, 168, 275

Screwpod 165

Metals xvii, 277, 295

and Woods, Comparison xvii, 2,

255

Metal Coatings, 273, 286, 295, 316,
400

Micro-organisms, Soil 275

Microscopes 31

Microscopic Examinations, 30, 31,
32, 247

Microtomes 31, 32

Middle Lamella (Wood Ele-
ment) 18

Mildew (see also Decay) 42

In Foliage 272

In Wood 42,268

Mineral Matter in Wood, 17, 236, 281

Missouri Corkwood 246

Mock Orange 204

Mocker Nut.. . 147,248

PAGE

Moduli and Weights of Woods, 33,

238, 239, 261

Moisture in Woods, 17, 26, 234, 237,
245, 246, 252, 258, 262, 263,
264, 265, 329
Mollusk (see also Shipworm), 225,

330

Monocotyledons, 4, 5, 6, 7, 224,
230

Morus 182

alba 182

celtidifolia 182

rubra 182

Mosses 269

Moths and Butterflies 320, 321

Goat 321

Gypsy 320

Mould in Wood 268

Movement, Sap 11

Mucilage (Defined) 62

Mulberry 182

Black 182

Mexican 182

Red 182,248,275

Tree, Virginia 182

White 182

Murier Sauvage 182

Mya arenaria 301

Myrtle-tree 196

N

Nails, Teredo 316

Worm 316

Names, Common and Botanical, 2, 47

Naphthalene 341, 342

National Forest Serv. Exper., 33,

258, 259, 260, 261

Natural Seasoning 276, 327

Naval Stores 15, 47, 53, 58

Nectandra 200

rodioei 200,201,246

Nectria cinndbarina (fungus) . . . 269
Needleleaf Trees and Woods, 4, 6,

29, 36, 43, 44

Negundo aceroides 138

Neowashingtonia filamentosa. . . 226

Nettle-tree 152

Nogal 141

INDEX

463

PAGE
Nomenclature, Trees and

Woods 2,47

Non-banded Trunks and

Woods 6,9,29,224

Non-coniferous Trees and

Woods 6,43,102,103

Non-durable Woods 275

Non-porous Woods 30, 31

Non-pressure Processes (Wood

Preservation) 353, 355

Non-seedbearing Plants 269

Noyer 141

Nyssa 186

aquatica 21, 186, 189

multiflora 190

ogeche 189

sylvatica 19, 187, 190

o

Oak, 3, 4, 5, 21, 24, 30, 43, 102, 104,
151, 152, 333, 334

African 212

Basket 107

Black 105,112,115

BlackLive 118

Box 109

Box White 109

Brash 109

British 119

Bur 105,110,248

California Live 105, 117

California Post Ill

California White Ill

Canyon 118

Canyon Live 118

Chestnut 105, 108, 119

Coast Live 117

Common 119

Cork 246

Cow 105,107,248

Dantzic 119

Durmast 119

Dyer's 115

English 104, 119

Evergreen 117

Garry 248

Golden-cup 118

Highland Live 118

PAGE

Oak, Indian 212

Iron 109,118

Live 105,116,118,246

Maul 118

Mossycup 110

Mossycup White 110

Mountain 108

Oregon White Ill

Overcup 109, 110, 248

Overcup White 110

Pacific Post 105, 111

Pin 32, 105, 113

Post 105,109,248

Quarter-Sawn 24, 39, 40, 334

Quercitron 115

Red, 20, 32, 105, 112, 114, 119,
150, 246, 275, 375

Rigi 119

Rock 108

Rock Chestnut 108

Scrub v. 110

Spanish 105,112,114

Spotted 115

Stave 106

Swamp Ill, 113,375

Swamp Chestnut 107, 108

Swamp Spanish 113

Swamp White. 107, 248

Tanbark 108,115

Valley Ill, 248

Valparaiso 118

Water 113

Water Spanish 113

Weeping. Ill

Western White Ill

White, 19, 22, 28, 31, 105, 106,
109, 111, 246, 248, 275, 375

Yellow 105, 115

Yellow-bark 115

Ochroma lagopus 214, 246

Oil 79,80,378,381,385

Boiled 379, 480

Cedar 380

China Wood 214, 379, 380

Citronella 380

Elaeococca 380

Linseed 379, 380, 383, 389

Lithographic 380

Non-solidifying 379, 381

464

INDEX

PAGE

Oil, Nut 143

Raw 379,380,392

Rubber 379

Sandal Wood 380

Solidifying 379, 380

Tung 214,379,380

Volatile 379, 381

Walnut 379

Oils, Paints and Varnishes 377

Oldfieldia 211

africana 211, 212

Olea europcea 127

Olive 127

California 196

Olive Tree 189

Wild 189

One-berry 152

Open Tank Process (Wood Pres-
ervation), 355, 356, 357,
358, 359, 360

Orange 127

Mock 204

Osage 92, 202, 204, 248, 275

Oreodaphne 196

Oreodoxa regia 6, 225

Organic and Inorganic Materials,

Comparison, xvii, 1, 233, 355
Organic Compounds in Woods, 9, 11,

19, 37, 234, 235, 236
Organic Origin, Influence upon
Properties of Woods, 233,
234, 235, 262, 264

Osage 204

Apple Tree 204

Orange 92, 202, 204, 248, 275

Ostrya 154

virginiana. 154, 155

Outside-growing Trunks 5, 6

Oxygen in Wood 234, 281

Ozonium omnivorum (fungus) . . 272

Padus serotina 205

Paint, Application of, 389, 390, 391,
392, 393, 394, 395, 398, 399,
400

Asbestos 284,401

Casein 389

Covering Capacity 394

PAGE

Paint, Denned 377

Durability of 398

Enamel 378, 398

Failure of 389, 390, 391

Fireproof 284, 285, 402

Miscellaneous Applications, 388,

389

Pigments, 378, 381, 382, 383, 384
Preparation of Woods to Re-
ceive 402

Priming for 380, 390, 393

Removal of 390, 391

Sprayed 391

Upon New Surfaces 390

Upon Old Surfaces 390

Water 389

Waterglass 285, 401

Woods Prepared For 402

Painting, Car 400

Coach 400

Ship... 399

Palm 4,7,224,225

Arizona 226

California Fan 226

Date 226

Desert , 226

Fanleaf 225,226

Nut 426

Royal 6,225

Sargent 225

Washington 225, 226

Palmacece 225

Palmetto 225,227

Cabbage 225,227

Mexican 225, 227

Prickly Thatch 227

Silktop 225,227

Silver Thatch 227

Silvertop 225

Paraffine 281, 316

Parasites (see Bacteria) 269

Parenchyma Cells .... 24, 30, 38, 39

Ray 30

Paris White, Pigment 389

Parthenium argentatum 427

Paulownia 180

Paulownia tomentosa 180

Pear 127

Tree, Wild 190

INDEX

465

PAGE

Pecan 148

Nut 148

Pecan-tree 148

Pecanier 148

Peckiness 93, 272

Penetrability 247

Pepper 213

California 213

Longleaved 213, 214

Pepperidge 190

Peppermint Tree 216, 223

Perishable Woods 275

Persimmon 30, 202, 203, 248

Black 193

Mexican 193

Peruvian Mastic 213

Phanerogams 269

Phloem 24, 34, 38

Phoe.nix dactylifera 226

Pholas 314

Pholas dactylus 314

Phosphorus in Wood 234

Phyllosticta acericola (fungus) . . 272
Physical Properties, India-
rubber 431

Woods, 18, 26, 33, 237-265

Physiological Processes of Trees, 8,

9, 10, 11, 12, 13, 233
Influence upon Properties of
Wood, 8, 9, 10, 11, 12,
233

Picea 64,65

alba 64,66,67

canadensis 67

engelmanni 64, 68

excelsa 64

mariana 66

nigra 64, 66, 67

rubens 64, 66

sitchensis 69

Piddock 314

Pieces, Edge-grained 40

Quarter-sawn 24, 39, 40, 334

Rift-grained 40

Straight-grained 40

Vertical-grained 40

Pigment, in Wood 17, 37

Barium Sulphate . . 382, 383, 434
Bismarck Brown . . . 388

PAGE

Pigment, Bone Black 384

Carbon 384

Chrome Green . . 382

Yellow 382

Graphite.. . .' 384

Iron Oxide 378, 383

Ivory Black 384

Litharge 383,434

Paris White.... 389

RedLead 383

Silica 383

White Lead 378,382

Zinc White 378, 382, 434

Pignut 146

Water 248

Pin, Knot 43

Rot 94

Pine, 3, 5, 30, 43, 44, 45, 49, 65, 67,
70, 72

Alaska 79

American White 48

Arizona Flexilis 49

Bastard 47,53,55,60,76

Bhotan 60

Big 50,56

Black 55,58

Black Norway 58

Black Slash 55

Blister 73

Brown 52

Bull 47, 49, 54, 55, 56, 60, 272

Canadian Red 57

Carolina 54

Common Yellow 54

Cornstalk 55

Cowdie 63

Cuban. . 46, 47, 53, 261

Dantzic 45, 59

Digger 60

Fat...'. 62

Finger Cone 51

Fir 73

Florida 52

Florida Longleaved 52

Florida Yellow 52

Foothills Yellow 56

Foxtail 55

Frankincense 55

Georgia (see Longleaf Pine) .

466

INDEX

PAGE

Pine, Georgia Heart 52

Georgia Longleaved 52

Georgia Pitch 52

Georgia Yellow 52

Gigantic 50

Ginger 92

Gray 60

Grayleaf 60

Great Sugar 50

Hard,45; 46, 47, 52, 54, 57, 58,61,70

Heart 52

Heavy 56

Heavy-wooded 56

Indian 55

Jack 60

Jersey 61

Kauri 62, 63, 387

Limber 49

Limber-twig 49

Little Sugar 50, 51

Loblolly. . . .46, 53, 55, 60, 261, 275

Lodgepole 60,275

Longleaf, 2, 28, 31, 46, 47, 52, 53,
261, 275

Longleaved 56, 58

Longleaved Pitch 52

Longleaved Yellow 52

Longschat 55, 58

Long Straw 52

Longstraw 55

Marsh 60

Meadow 53, 55, 60

Mexican White 46

Montana Black 56

Monterey 60

Mountain 51

Mountain Wey mouth 51

Murray 60

North Carolina 54, 55, 60

North Carolina Pitch 52

North Carolina Yellow 54

Northern 45,48,59

Norway 57

Nut 46

Old Field • 54,55

Oregon 46,47,70,71

Pacific 70

Parry's 46

Patternmaker's . 48

PAGE

Pine, Pifion 20

Pitch 47,52,53,54,56,58

Pond 60

Poor 54

Puget Sound 71

Pumpkin 48

Red 56,57,71

Rigid 58

Rocky Mountain 49

Rocky Mountain White 49

Rosemary 52, 54, 55

Sabine 60

Sap 55,58

Scotch 59

Scrub 60

Shade 50

She 53

She Pitch 53

Shortleaf 46, 47, 54, 55, 261

Shortleaved Yellow 54

Shortshat 54

Silver 46,51,73

Slash 53,54,55

Soft 45,48,51

Southern 2,52

Southern Hard. ...... 46, 52, 261

Southern Hard Dense 261

Southern Hard Sound 260

Southern Heart 52

Southern Pitch 52

Southern Yellow 52, 56, 260

Spruce. ..... 47, 48, 53, 54, 55, 60

Stone. 60

Sugar 45,46,50

Swamp 53, 55

Tamarack 60

Texas Longleaved 52

Texas Yellow 52

Torch 55

Turpentine 52

Virginia 55

Virginia Yellow 54

Western Pitch 56

Western White 46, 51

Western Yellow, 20, 23, 25, 50, 56,

275

Weymouth 48

White, 45, 46, 48, 49, 50, 51, 58,

59, 64, 68, 171, 246

INDEX

467

PAGE

Pine, White Blister Rust 48, 50

Whitebark 46

Yellow. ... 2, 47, 52, 54, 55, 56, 58

Yew 66

Finite 50

Pinus 45, 65

albicaulis 46

caribtea 53

cembra 60

cembroides 46

divaricata 60

echinata 46, 47, 54

edulis 20

excelsa 60

flexilis 46,49

glabra 60

heterophylla 46,47,53

lambertiana 45, 46, 50

mitis 54

monticola 46, 51

murrayana -. . . 60

palustris, 2, 5, 46, 47, 52, 53,
246

ponderosa 20, 23, 25, 56, 272

quadrifolia 46

radiata 60

resinosa 57

rigida 58

sabiniana 60

serotina 60

strobiformis 46

strobus 45, 48, 59, 171, 246

sylvestris 45, 59

tceda 46, 47, 53, 55

taxifolia 70

virginiana 61

Piquant Amourette 167

Pistacia lentiscus 388

Pitch 53,54,64

Tubes 64

Pith 24,34,37

Cavity 24,34,37

Knot 42

Ray 22, 24, 26, 40, 249

Ray Cells 19

Ray Primary 24

Ray Secondary 24

Pits 18, 19, 20, 21, 102

Bordered.. 20

PAGE

Pits, Simple 18, 19, 20, 23, 102

Plane, American 156

Common 156

Oriental 156

Tree 156,157

Planks 40

Plants, Non-Seedbearing 269

Seedbearing 4, 269

Plaqueminier 203

Platane 157

Platanus 156

occidentalis 156, 157, 158, 246

orientalis 156

racemosa 156, 158

Plum, Date 203

Gopher 189

Polished Wood, Specification

for 398,400

Surfaces, 395, 396, 397, 398, 399,
400

; Polymerization 435

Polyporus carneus 86

Polyporus juniperus 86

Poplar 3, 73, 169, 171, 172

Balsam 169

Bay 186

Blue 171

Carolina 173

Hickory 171

Large 172

Largetooth 172

Necklace 173

Tulip 171

White 171, 172

Yellow 171,248

I Popple 171,172

I Populus 169

balsamifera 73, 169, 174

deltoides 173

grandideritata-, 172

monilifera 173

tremuloides 169, 172

trichocarpa 174

i Pores 21, 30, 247, 249, 375

j Porosity (Defined) 247

Wood 37, 237, 247, 248

Porthetria dispar 320

j Possumwood 203 *

Potassium in Wood . . . 234

468

INDEX

PAGE

Powell Process (Wood Preserva-
tion) 374 ;

Preference for Wood 2 \

Preparation of Wood for Fire

Coatings 284 '

Glue 408 i

Internal Preservative Treat-
ment 353, 374 i

Paints, Oils and Varnishes, 284, j
402

Seasoning 328

Test Pieces 255, 256 j

Preservatives, Wood, 265, 317, 335,
337, 338, 339, 340, 341, 342, \
343,344,345,346,347,348, j
349, 350, 351, 352, 353, 375,
377, 379, 380, 381
Pressure, Influence upon Preser-
vative Treatment. . . . 361

Prickly Thatch 227

Pride of India 214

Primary, Canal 26

Pith-Ray 24

Resin-duct 25

Wall • 19

Wood 10

PrimaVera 207,210

Principles of Fire Protection, 292,
293, 294, 295, 296, 297, 298,
299

Prionoxystus robinice 321

Properties of Structural Mate-
rials xvii, 1

Properties of Woods, Chemical

Composition, 9, 26, 233,
234, 235. 281
due to Organic Origin, 233, 234,

235

Physical, (see Physical Prop-
erties of Wood}, 263, 264,265
Physiological, 8, 9, 10, 11, 12,
233

Special 233

Prosopis 165

juliflora 165, 168

odorata . 165

Protection of Glue 410

Protection of Wood

Allardyce Process 371

PAGE

Protection of Wood

Bethell Process 363, 371

Boiling Process 372

Boucherie Process 372

Brush Applications 354

Burnett Process 368

Card Process 371

Charring 373

Creoaire Process 374

Creo-resinate Process 372

Dipping Brush and Soaking

Applications 354

Empty Cell Processes, 351, 361,

362, 369, 370, 371
External Treatment, 284, 285, 286,

315, 377, 378, 389, 390, 391,
392, 393, 394, 395, 396, 397,
398, 399, 400, 401, 402

Ferrell Process 374

from Burning, 282, 283, 284, 285,
286

from Rot 273, 274, 275, 276

from Wood Borers, 309, 310, 313,
315,316,317,318,320,321,
322, 323, 324
Full Cell Processes, 351, 361, 362,

363, 368, 369

Hasselmann Process 374

Hayford Process 364

Internal Treatment, 282, 283, 284,

317, 318, 335, 336, 337, 351,
352, 353, 354, 355, 356, 357.
358, 359, 360, 361, 362, 363,

364, 365, 366, 367, 368, 369,
370, 371, 372, 373, 374,
375

Kyan Process 355

Lowry Process 370

Miscellaneous Processes 373

Non-pressure Processes . .353,, 355
Open Tank Process, 355, 356, 357,

358, 359, 360

Powell Process 374

Pressure Processes. 353,360-373

Robbins Process 373

Ruping Process .... 361, 369, 371

Rutgers Process 371

Seasoned Woods, 266, 276, 334,

377, 402

INDEX

469

Protection of Wood, Seasoning, 326,
327, 328, 329, 330, 331, 332,
333, 334

Seeley Process 373

Superficial Processes ....

Thilmany Process

Vulcanizing

Wellhouse Process

Woods that Respond to .

Zinc Chloride Process . . .

Zinc Creosote Process . . .

Zinc Tannin

Protoplasm 11, 19,37

Prunus 202

serotina

Pseudophcenix sargentii

Pseudotsuga

douglasii 71

macrocarpa

mucronata 1

taxifolia 47, 71

Pterocarpus erinaceus 214

santalinus 215

Pterocarya caucasica 141

Pullman Specif., Car Paint-
ing 400

Putty 393

Pyrus augustifolia 127

communis 127

coronaria.. . 127

PAGE
326

Ouercus obtusiloba

PAGE
. . 109

332

palustris

105, 113

pedunculata . .

105, 119

373
353
374

prinus
pubescens
robur . . .

105, 108
... 119
. . 105

373
371
374
368
371
371

robur intermedia
robur var. pedunculata . 3,
robur var. sessiliflora
rubra 3,20, 105, 112,
sessiliflora
stellata

. .. 119
104, 119
104, 119
150, 246
105, 119
. 109

236

tinctoria

... 115

202

triloba

. 114

205

velutina

105, 115

225

virens

... 116

70

virginiana 105,

116, 246

71

wislizeni

... 118

70
,246

R

mains . .

127

rivularis. . .127

Q

Quartered Surfaces . . 24, 39, 40, 334

Quartz Ground, Pigment 383

Quercus. 3,21,104

agrifolia 105 117

alba 3, 19, 22, 105, 106, 246

chrysolepis 105, 118

cuber 246

digitata 105, 114

falcata 114

garryana 105, 111

lobata Ill

macrocarpa 110

michauxii 105, 107

minor 105, 109

Racine Boats 411

Radial Surfaces of Wood 39

Railroad Spikes, Holding Power 242
Railway Eng. Assn. Specif, for

Creosote 344,345

Rainfall 14

Range of Species. . 16

Rattan 232

Ray Parenchyma 301

Ray-tracheid 24

Razor Clam 301

Recorders, Watchmen's 299

Red Flower 136

Red Lead Pigment 383

Redwood, 27, 36, 46, 72, 86, 98, 99,
100, 101, 208, 275

California 101

'Coast 101

Common 98, 99, 101

Curly 98

Giant 101

Mammoth 98, 99, 101

Resilience, Wood 237, 241

Resin, 2, 4, 17, 25, 26, 44, 45, 46, 47,
57, 62, 234, 235, 246, 247,
385, 386, 387, 388, 432

Amber 385, 386

Anime 386

470

INDEX

PAGE

Resin, Canal (see Resin Ducts)

Copal 386

Dammar 385, 387, 388

Duct ... 23, 24, 25, 26, 28, 45, 247

Primary 25

Secondary 25

Fossil 62,385,386,387

Fresh-product 62

Guajac 191

Kauri 62, 63, 385, 387, 388

Mastic 385,388

Pine 388

Sandarach 387

Semi-Fossil 62

Shellac 387, 392, 397

Solvents 378, 379, 380, 381

Varnish. ... 62, 385, 386, 387, 388

Zanzibar 386

Resonance (Denned) 249

Wood 237,249

Rhapis flabelliformis 232

Rhododendron 195

maximum 193, 195

Rift-grained Pieces 40

Rigidity (Denned) 239

Wood 237,239

Rings, Bands, or Layers, Annual, 5,
6, 10, 11, 29, 30, 34, 35, 36,
37, 102, 360

Ring-porous Woods 30, 31

Robbins Process (Wood Preser-
vation) 373

Robinia 165

pseudacacia 165, 166, 246

Roble 210

Rolled Lumber 41

Root, Diseases 272

Fungi...' 272

I\mgous Diseases 272

Rot, Southern 272

System of Tree 8

Rose Bay 195

Rosewood 214

African 214

Brazilian 214

California 215

Canary 214

Rosin.. 388,434

Rot, Black Scale 214

PAGE

Rot, Chestnut Bark 149, 150

Dry 42,268, 274,401

Pin 94

Red 86

Soft 42

Wet 42, 268, 274

White 86, 121

Wood 268, 273, 274, 275, 276

Rotary-cut 40

Rotten Knot 43

Round Knot 43

Rubber, (see Indiarubber).

Oil 379

Tree 213,427

Rueping Process (Wood Preser-
vation) 361, 369, 371

Rule, Density 46, 260

Rupture, Modulus of. . 33, 239, 261

RustinWood 42,268

Rutgers Process (Wood Preser-
vation) 371

Sabal mexicana 225, 227

palmetto 225, 227

Sabicu 213

Sagwan 212

Salix . . . 177

alba 177, 178

caprea 177

fluviatilis 177

fragilis 177

nigra 178

russeliana 177

Sand Flea 310

Sandalwood 215

Oil 380

Red 215

Sandarach 387

Sanderswood 215

Santalin 215

Santalum 215

album 215

! Sap, 11, 20, 21, 37, 38, 235, 262, 263

Circulation of 11, 20,21

Crude 11,235

Effect upon Properties, 26, 262, 263

Elaborated 11,37,235

Movement.. ... 11, 20, 21

INDEX

471

PAGE

Saprophytes 269

Sapwood, 25, 34, 37-, 38, 47, 120, 144,
246, 247, 262, 351

SasifraxTree , 199

Sassafac 199

Sassafrac 199

Sassafras 198,199

Calif ornian 196

Sassafras 198

officinale 199

sassafras 199

Satinwood 215

East Indian 215

Savin 87

Saxifrax 199

Schcefferiafrutescens 193

Schinus molle 213

terebinthifolius 214

Scolytidce 319

Season, Influence upon Cutting, 262,

263
Seasoned Woods, Protection of, 266,

276, 334, 377, 402

Seasoning of Woods, 266, 276, 326,
327, 328, 329, 330, 331, 332,
333, 334, 402

Air 327

Kiln-drying, 328, 329, 330, 331,
332, 333, 334

Natural 327

Water 327, 328

Yard Drying.. 327

Secondary, Canals 26

Pith-ray 24

Resin-duct 25

Wall 19

Wood 10

Second-growth Woods 120, 144

Seedbearing Plants 269

Seeley Process (Wood Preserva-
tion) 373

Semi-vulcanite 434

Sequoia, 27, 36, 86, 98, 99, 100, 101

Sequoia 86,98

sempervirens 98, 101

washingtoniana 98, 101

Shagbark 145

Shakes (Defects) 41

Shapes of Trees 12, 13

PAGE

Shawneewood 180

Shellac. 385, 387, 390, 392, 397, 398

Shellbark 145

Shinglewood 90

Ship-painting 399

Shipworm, 98, 225, 300, 301, 302,
303, 304, 305, 306, 307, 308,
309, 310, 311, 312, 313, 314,
315, 316, 317, 318, 340

Boring Shell 303

Calcareous Lining 303

Collar 302,303

Excavations 307

Field of Attack. 309

Foot 303

Form 301

Influence of Temperature and

Water 306

Method of Attack 307

Pallets 302

Protection from 315

Rapidity of Work 308

Reproduction and Develop-
ment 305

Siphon 302

Size of Borings 308

Woods, Subject to Attack,309, 310
Shutters, Fire. . . 284, 285, 295, 296

Sieve Tubes 38

Signals, Fire 298

Silica, Pigment 383

Silverbell 248

Silver Fish 320

Thatch 227

Simmon 203

Simple Pits 18, 19, 20, 23, 102

Sipiri 201

Sissoo 213

Slab 40

Slash-cut Pieces 40

Slice-cut Pieces 40

Smoking Bean 181

Soaking (Preservation of Wood) 354

Soft Bast 38

Soft Rot 42,268

Softshelled Clam 301

Softwoods 4, 6, 30, 43, 44

Sorbus 126

americana. . . 126

472

INDEX

PAGE

Sorbus, sambucifolia 126

Sound, Conductivity of Wood . . 248
Special Properties of Woods . . . 233

Sound Knot 42

Southern Creosoting Co., Specif. 364

Soymida 206

febrifuga 206

Spanish Bayonet 228

Dagger 228

Spar Varnish 386

Special Properties of Woods . . . 233

Species 3, 16

Defined 3

Distribution of 16

Number of 3

Specifications, Analysis of Creo-
sote, 346, 347, 348, 349, 350
Amer. Railway Engr. Assn.

(Defects) 42

Amer. Society for Testing

Materials (Defects) ... 42

Application of Cattle Glue, 408, 409

Application of Creosote, 358, 359,

360, 364, 365, 366, 367,

368, 370

Application of Fish Glue. . . 414
Application of Paint, 391, 392,
393, 394, 398, 400

Automatic Sprinklers 297

Car Painting '. 400

Creosote, 344, 345, 346, 347, 348,
349, 350

Defects in Wood 42

Density Rule for Grading

Southern Hard Pine . . 260
Hardwood Mfrs. Assn. of the

U. S. (Defects) 42

Open Tank Process (Wood

Preservation) 358

Pacific Coast Lumber Mfrs.

Assn. (Defects) 42

Wood Polishing 398, 400

Yellow Pine M|rs. Assn. (De-
fects) 42

Zinc Tannin Process (Wood

Preservation) 371

Specific Gravity of Wood . . 237, 244
Specimens, Wood Testing, 252, 255,
256

PAGE

Sphceroma destructor 314

Spice-tree 196

Spike Knot 43

Spikes, Holding Power 242

Spiral (Wood-element) 20

Spiritine 352

Spores Fungi 269

Spot in Foliage 272

Spring Deposit 30, 31, 35, 36

Spring Wood (see Spring Deposit) .
Sprinklers, Automatic, 289, 295, 297,

298

Spruce, 28, 29, 43, 44, 46, 64, 65, 66,
67, 70, 71, 72, 80

Big Cone 70

Black 60,64,66,67

Blue 66

Bog 67

California Hemlock 79

Cat 67

Cork-barked Douglas 71

Destroying Beetle 64

Double 66,67

Douglas 47, 64, 70, 71

Engelmann's 68

Great Tideland 69

He Balsam 66

Hemlock 78,80

Kauri 64

Menzies 69

Mountain 68

Norway 64

Pine 66

Prickly 60

Red 64,66,70

Single 67,73

Sitka 69,275

Skunk 67

Tideland 69

Water 66

Western 69

White 60, 64, 66, 67, 68, 275

Stains for Wood 388, 398

Standard, Knot 43

Moisture in Wood 252

Star Shakes (see Defects in

Wood) 41

Steam, Influence upon Wood, 361,
362

INDEX

473

PAGE

Stinkwood 190

Stone-borers 314

Stones, Building xvii, 277, 295

Stones and Woods, Comparison', xxii,
1,255

Stores, Naval 15, 47, 53, 58

Straight-grained Pieces 40

Streamflow 14

Strength (Defined) 237

Strength of Wood Influenced by

Moisture 262,264

Strength of Sapwood and Heart-
wood 37

of Woods, 33, 37, 237, 238, 239,
240, 241, 242, 243, 244, 245, 246,
247, 248, 249, 250, 251, 252,
253, 254, 255, 256, 257, 258,
259, 260, 261, 267

Stringybark 216, 223

Structure, Wood (see Wood

Structure) .
Structures, Maintenance of. ... 298

Suberin 39

Sugarberry 152

Sugar Cane 224

Sugar Tree 134

Sulphur in Wood 236

Sumach 193

Summer Deposit 30, 31, 35, 36

Summerwood (see Summer De-
posit) .

Summer-felled Wood 262, 263

Sunlight, Influence on Tree. . 12, 13

Supeira 201

Superficial Processes (Wood

Preservation) 353

Surface Treatment of Woods, 284,
315, 377, 389, 390, 391, 392,
393, 394, 395, 396, 397, 398,
399, 400, 401, 402

Surfaces, Cross (Wood) 39

Quarter-sawn (Wood) 24, 39, 40,
334

Radial (Wood) 39

Tangential (Wood) 39

Swamps 83, 85, 86

Cedar - 85

Cypress 86

Tamarack 83, 86

PAGE

Swietenia 206, 207

mahagoni 206, 207, 208, 246

Sycamore, 30, 156, 157, 158, 246,

248, 275
California 156, 158

System, Central Office 299

Tabebuiadonnell-smithii. . . 207, 210

Tacmahac 174

Tamarack 60, 81, 83, 84

Red 83

Swamp 86

Western 84

White 83

Tanbark 2

Tangential Surfaces 24, 39

Tannic Acid (see Tannin).
Tannin, 37, 203, 234, 235, 337, 338
Tar (see Naval Stores).. . 46, 47, 316

Taxodium 95

distichum 96, 97, 246

Taxus 92

bacata 20

brevifolia 92

floridana 92

Teak 211,212

African....'. 211,212

Burma *. . . 212

Indian 212

Malabar 212

Tectona 211

grandis 211,212

Teek 212

Telephone & Tel. Co. Specif, for

Creosote 346,347

Temperatures, Destructive 293

Effect upon Wood 293, 329

Teredo, (see Shipworm).

Teredo Nails 316

Teredo dilatata 301

megotara 301

navalis 300, 301

norvegica 301

thompsoni 301

Termes bellicosus 322

flavipes 322

lucifugus . 322

474

INDEX

PAGE

Termites 201,321

Protection from 322

Summarized 323

Woods Destroyed by 322

Terrestrial Woodborers, 18,300, 318,
319, 320, 321, 322, 323, 324,
325

Woods Destroyed by, 319, 320,
321, 322, 323, 324

Woods Protected from 324

Test, Density 46, 245, 260

Test Machine, Impact 245

Test-pieces, Wood 252, 255, 256,

258, 259
Tests, "Fireproof ed Woods, "286, 287

Glues 417, 418, 419, 420

Woods, Physical Properties of, 33,
242,243,244,251,252,255,
256, 257, 258, 259, 261
Woods, Natl. Forest Service, 33,

258, 261

Woods, U. S. Census, 33, 257, 261
Woods, Watertown Arsenal . . 33

Tewart 222

Thickness-growth of Trees. . . 10, 12
Thilmany Process (Wood Pres-
ervation) 374

Thorn 167

Thorny Locust 167

Thrinaxmicrocarpa 225, 227

parviflora 225,227

Thuya 85

gigantea 86, 90

occidental 86,89

plicata 90

Thysanura 319

Tidy Specif, for Creosote 344

Tiel 170

Tieltree. . .170

americana
heterophylla
Timber (Defined)

.. 170,176
176
17

Tooart

222

Toothache Trees
Top-soil
Influence upon Rot . . .
Torchwood

126
13, 14
275
21

Torus

. ... 18,20

PAGE

Toxylon 202

pomiferum 202, 204

Tracheae (Wood Elements) .... 21
Tracheal-tubes (Wood Ele-
ments) 21

Tracheid (Wood Elements), 11, 19,
20, 22, 23, 24, 25, 30, 44,

102, 247

Tree (Defined) 8

of Heaven 172

Yucca 229

Trees and Woods, Banded (see

Trunks and Woods, Banded).
Broadleaf, 4, 5, 6, 29, 43, 44, 102,

103, 169, 333
Coniferous, 4, 5, 6, 20, 29, 43, 44,

102

Deciduous 4, 6, 43, 103

Dicotyledonous, 4, 5, 6, 30, 34, 43,

102, 169

Evergreen. 4, 5, 6, 20, 34, 43, 44,
102

Hardwood 4, 6, 43, 102

Identification of, 17, 27, 28, 29, 30,

31, 32, 36
Monocotyledonous, 4, 5, 6, 7, 224,

230

Needleleaf, 4, 5, 6, 20, 29, 36, 43,
44, 102

Non-banded 6, 9, 29, 224

Softwoods 4, 6, 43, 44

Trees, Forms of 12, 13

Fungous Diseases 271

Influence of Sunlight 12, 13

Inside-growing 6, 7, 9, 224

Leaf Systems of 9

Length-growth of 9

Number of 3

Outside-growth of, 5, 6, 9. 29, 30,

34,43,44, 102,169,224
Physiology of, 8, 9, 10, 11, 12, 13

Root System of 8

Shapes of 12,13

Thickness-growth of 10, 12

Trunk System of 9

Trichophyton tonsurans (fun-
gus) 270

Trunks 9,16,34

Fungous Diseases of 272

INDEX

475

PAGE

Trunks and Woods, Banded, 5, 9, 29,

30, 34, 43, 44, 102, 169, 224

Non-banded 6, 9, 29, 224

Tsuga 65, 78

canadensis 80

caroliniana 80

heterophylla 78

mertensiana 78, 79

Tuart 216,222

Tubes (see Wood Elements] 21

Pitch 64

Sieve 38

Tulip 102

Tulip-tree 169, 171, 175

Tung Oil 214, 379, 380

Tree 214

Tupelo 189,190,275

Large 189

Sour 189

Swamp 189

Turpentine, 2, 25, 46, 47, 53, 54, 57,

60, 62, 381, 399, 435
Venice 62,82

Xyloses 21, 247, 248, 375

U

Ulmus

alata

americana

fulva

.... 128
.... 132
.... 129
.. 3,131

pubescens 129, 131

racemosa 130

thomasi 130

Umbellularia calif ornica. . . 195, 196

Umbrella Tree 214 ;

Unbled Woods 46,47 j

United States Census, Exper., 33, !
257, 261

Unknown Tree 152 j

Use, Wood Destroyed by 266

Uses of Wood. . 2

Variety (Botanical) 3

Varnish, xviii, 377, 378, 379, 385, 386,

387, 388, 395, 396
Application of, 395, 396, 397, 398,

399
Japan 380,381

PAGE

Varnish, Oil 62, 378, 385

Resins 62, 385, 386, 387

Spar 386

Spirit 62,378,385

Woods to Receive 402

Varnishes, Oils, and Paints .... 377

Vasa 21

Veneer 40, 414, 415, 416, 417

Veneers, Rotary Cut 169

Veneered Work, Appearance of . 417

Economy of 417

Preparation of 416

Stability of 417

Uses of 414

Venice Turpentine 62, 82

Vertical Grain in Woods 26

Grain Pieces 40

Vessels, 19, 21, 28, 30, 44, 247, 375

Vessel-segments 21

Vitse 29

Vitality of Wood 267

Vulcanite 434

Vulcanite-semi 434

Vulcanization, Ihdiarubber, 430, 431,

434

Vulcanization (Wood Preserva-
tion) 373,430,431,434

Vulcanized Rubber.. . . 430, 431, 434

W

Wahoo 132

Wain 40

Wall (Wood Element) 19

Walls, Primary 19

Secondary 19

Walnut, 3, 19, 21, 22, 139, 142, 143,
144, 145

American 140

Arizona 140

Austrian 141

Black, 19, 21, 22, 23, 30, 139, 140,
142, 188, 248

California 140

Caucasian 141

Circassian 139, 141, 186, 215

Dwarf 140

English 139,141,209

European 139, 141

476

INDEX

PAGE

Walnut, French 141

Italian 141

Little 140

Mexican 140

Oil ; 379

Persian 141

Royal 139, 141

Russian 141

Satin 141, 186,188

Shagbark 145

Sweet 145

Turkish 141

Western 140

West Indian 141

White 139,140,143,210

Washingtonia filifera 225, 226

Watchman's Recorders 299

Water in Wood, 17, 26, 234, 237, 245,
246, 252, 258, 262, 263, 264,
265, 329

Paints 389

Seasoning of Wood 327, 328

Waterglass, Paint 285, 401

Watertown Arsenal Experi-
ments 33,257,261

Weathering of Woods 267

Weights of Woods, 18, 33, 237, 244,

245, 246, 247, 261, 267
Weights and Moduli for Woods

(Summaries) 33, 261

Wellhouse Process (Wood Pres-
ervation) 371

Wet Rot in Wood 42, 268, 274

Whahoo 132

White, Ant (see Termite)

Lead Pigment 378, 382

Pine Blister Rust 48,50

Whitewash 389

Whitewood ... 46, 169, 171, 173, 176

Whiting 389

Wickup . 176

Wild Date 254

Willow 177, 178,213

Basket 177

Bedford 177

Black 178

Crack 177

Desert 248

Goat.. . 177

PAGE

Willow, Longleaf 177

Osier 177

Sandbar , 177

Swamp 178

White 177,178

Windfalls 65, 121

Windows, Fireproof 296

Wind Shakes in Wood (Defects), 41,
333

Winter Felled Wood 262, 263

Wired Glass. 296. 297

Wood, Banded, 5, 6, 9, 29, 30, 34, 43,
44, 102, 169, 224

Bled 46,47

Broadleaf, 4, 5, 6, 29, 36, 43, 44,

102, 103, 169, 333
Cells (see Wood Elements).
Chemical Composition of, 9, 13,
26, 37, 38, 39, 233, 234, 235,
236, 237, 281
Coloring Matter in, 17
Coniferous, 4, 5, 6, 26, 29, 30, 34,
36, 43, 44, 102, 103

Consumption of 1, 2

Deciduous 4, 6, 43, 103

Defects in 40, 41, 42, 43, 333

Defined 17

Density of 237,244

Destroyed, by Age 266, 267

by Ants , 321,323,324

by Bees 323

by Beetles 319,320

by Chelura 313

by Decay (see Decay in Woods) .

by Exposure 267

by Fire, 277, 280, 281, 282, 283,

284, 285, 286

byLimnoria.. 310,311,312,313
by Miscellaneous Wood-
borers 314

by Moths andButterflies, 320,

321

by Shipworms, 225, 300, 307,
308, 309, 310, 315, 316, 317,
318

by Termites 321, 322, 323

by Use 267

Dicotyledonous, 4, 5, 6, 30, 34, 36,
43,102,169

INDEX

477

PAGE

Wood. Diffuse-porous 30, 31

Durable 266, 274, 275, 276

Elements, 11, 17, 18, 19, 20, 21, 22,
23, 24, 25, 26, 27, 28, 29, 30,
31, 34, 38, 39, 44, 45, 102,
224, 225, 237, 247, 248, 249,
252, 375

Evergreen 4, 6, 43, 44, 81

First-growth 120

Flea 310

Hard (see Broadleaf Woods).

Heart 25, 34, 37, 247, 351

Hygroscopicity 251

Identification of 17, 27, 32, 36

Importance of....xvii, xviii, 1
Monocotyledonous, 4, 5, 7, 224, 230
Needleleaf (see Coniferous
Woods).

Nomenclature 2, 47

Non-Banded 6, 9, 29,224

Non-Durable (see Perishable

Woods).

Non-Coniferous (see Broadleaf
Woods).

Non-Porous 30, 31

Parenchyma 24, 30

Physical Properties of, 18, 26, 33,
237, 251-265

Porous 30, 31, 37

Prepared for Fire Coatings . . . 284

for Glue.. . 408

for Internal Preservative

Treatment 353, 374

for Paints and Other Coat-
ings 284,402

for Seasoning '. 328

for Test Pieces 255, 256

Preservatives (see Preserva-
tives of Wood).

Primary 10

Protected from Burning, 282, 283,

284, 285, 286

from Rot. . . . 273, 274. 275, 276

from Woodborers, 309, 310, 313,

315, 316, 317, 318, 320, 321,

322, 323, 324

Wood, Sapwood, 25, 34, 37, 38, 47,

120,
351

144, 246, 247, 262,

PAGE

Wood, Secondary 10, 19

Second-growth 120, 144

Soft 4, 6, 20, 30, 38, 43, 44

Special Properties of 233

Spring 35

Summer 35

Vitality of 267

Woodborers, Land, .300, 318, 319,
320, 321, 322, 323, 324. 325
Marine, 95, 225, 300, 301, 302, 303,
304, 305, 306, 307, 308, 309,
310, 31.1, 312, 313, 314, 315,
316, 317, 318, 340

Miscellaneous 314

Protection from, 315, 316, 317,
318, 320, 321, 322, 323, 324,
325

Woods and Trees (see Trees and
Woods).

Wool, Cotton 234

Worm, Carpenter 321

Nails 316

X

Xanthoxylum americana 126

clava-herculis 126

cribrosum 215

Xylem 24,34

Xylocopa virginica 323

Xylophaga dorsalis 301

Xylotrya 300

fimbriata 301, 305, 306

Yearly Bands, Rings, or Layers
(see Annual Rings,
Bands or Layers).

Yellow Bark 121

Yellow Pine Mfrs. Asso. Specif. . 42

Yellow-wood 193, 204, 205

Yew 20, 92

California . 92

Florida 92

Oregon .- 92

Western 92

Yucca 224, 228, 229

Aloe-leaf . . .228

478

INDEX

PAGE

Yucca, Breadfruit 228

Cactus 229

Mohave 228

Schott 228

Tree 229

Yucca 228

aloifolia 228

arborescens 228, 229

brevifolia 228, 229

constricta 228

gloriosa 228

PAGE

Yiicca, macrocarpa 228

mohceuensis 228

treculeana 228

Z

Zanzibar 386

Zinc Chloride Processes 368, 371

Creosote Process 371

Oxide 382, 434

Tannin Process Specif 371

White Pigment 378, 382, 434

REC'D Lt

OCT8 '64.5

TA.4 . 3C5844

UNIVERSITY OF CALIFORNIA LIBRARY