CONTENTS

PAGE
LIST OF ILLUSTRATIONS[xiii]
ACKNOWLEDGMENTS[xxi]
CHAPTER
I.INTRODUCTORY[1]
II.FORM
Form as important as substance. Why a joist is stiffer than a plank. The girder isdeveloped from a joist. Railroad rails are girders of great efficiency as designed and tested by Mr. P. H. Dudley		[5]
III.FORM CONTINUED. BRIDGES
Roofs and small bridges may be built much alike. The queen-posttruss, adapted for bridges in the sixteenth century, neglected for two hundred years and more. A truss replaces the Victoria TubularBridge. Cantilever spans at Niagara and Quebec. Suspension bridges at New York. The bowstring design is an arch disguised. Why bridges arebuilt with a slight upward curve. How bridges are fastened together in America and in England		[18]
IV.FORM CONTINUED. LIGHTNESS, EASE IN MOTION
Why supports are made hollow. Advantages of thearch in buildings, bridges and dams. Tubes in manifold new services. Wheels more important than ever. Angles give way to curves		[39]
V.FORM CONTINUED. SHIPS
Ships have their resistances separately studied. This leads toimprovements of form either for speed or for carrying capacity. Experiments with models in basins. The Viking ship, a thousand years old,of admirable design. Clipper ships and modern steamers. Judgment in design		[52]
VI.FORM CONTINUED. RESISTANCE LESSENED
Shapes to lessen resistance to motion. Shot formed tomove swiftly through the air. Railroad trains and automobiles of somewhat similar shape. Toothed wheels, conveyors, propellers andturbines all so curved as to move with utmost freedom		[65]
VII.FORM CONTINUED. ECONOMY OF LIGHT AND HEAT
Light economized by rightly-shaped glass. Heatsaved by well-designed conveyors and radiators. Why rough glass may be better than smooth. Light is directed in useful paths by prisms.The magic of total reflection is turned to account. Holophane Globes. Prisms in binocular glasses. Lens grinding. Radiation of heatpromoted or prevented at will		[72]
VIII.FORM CONTINUED. TOOLS AND IMPLEMENTS
Tools and implements shaped for efficiency. Edge toolsold and new. Cutting a ring is easier than cutting away a whole circle. Lathes, planers, shapers, and milling machines far out-speed thehand. Abrasive wheels and presses supersede old methods. Use creates beauty. Convenience in use. Ingenuity spurred by poverty inresources		[89]
IX.FORM CONTINUED. ABORIGINAL ART
Form in aboriginal art, as affected by materials. Old formspersist in new materials. Nature’s gifts first used as given, then modified and copied. Rigid materials mean stiff patterns. Newmaterials have not yet had their full effect on modern design		[108]
X.SIZE
Heavenly bodies large and small. The earth as sculptured a little at a time. Thefarmer as a divider. Dust and its dangers. Models may mislead. Big structures economical. Smallness of atoms. Advantages thereof. Dustrepelled by light		[120]
XI.PROPERTIES
Food nourishes. Weapons and tools are strong and lasting. Clothing adorns andprotects. Shelter must be durable. Properties modified by art. High utility of the bamboo. Basketry finds much to use. Aluminium, howproduced and used. Qualities long unwelcome or worthless are now gainful. Properties created at need		[135]
XII.PROPERTIES CONTINUED
Producing more and better light from both gas and electricity. TheDrummond light. The Welsbach mantle. Many rivals of carbon filaments and pencils. Flaming arcs. Tubes of mercury vapor		[154]
XIII.PROPERTIES CONTINUED
Steel: its new varieties are virtually new metals, strong, tough, andheat resisting in degrees priceless to the arts. Minute admixtures in other alloys are most potent		[163]
XIV.PROPERTIES CONTINUED
Glass of new and most useful qualities. Metals plastic under pressure.Non-conductors of heat. Norwegian cooking box. Aladdin oven. Matter seems to remember. Feeble influences become strong in time		[180]
XV.PROPERTIES CONTINUED. RADIO-ACTIVITY
Properties most evident are studied first. Then thosehidden from cursory view. Radio-activity revealed by the electrician. A property which may be universal, and of the highest import. Itsstudy brings us near to ultimate explanations. Faraday’s prophetic views		[197]
XVI.MEASUREMENT
Methods beginning in rule-of-thumb proceed to the utmost refinement. Standardsold and new. The foot and cubit. The metric system. Refined measurement as a means of discovery. The interferometer measures15,000,000inch. A light-wave as an unvarying unit of length		[208]
XVII.MEASUREMENT CONTINUED
Weight, Time, Heat, Light, Electricity, measured with new precision.Exact measurement means interchangeable designs, and points the way to utmost economies. The Bureau of Standards at Washington. Measurementin expert planning and reform		[219]
XVIII.NATURE AS TEACHER
Forces take paths of least resistance. Accessibility decides where citiesshall arise. Plants display engineering principles in structure. Lessons from the human heart, eyes, bones, muscles, and nerves. Whatnature has done, art may imitate,—in the separation of oxygen from air, in flight, in producing light, in converting heat into work:Lessons from lower animals. A hammer-using wasp		[245]
XIX.QUALIFICATIONS OF INVENTORS AND DISCOVERERS
Knowledge as sought by disinterested inquirers.A plenteous harvest with few reapers. Germany leads in original research. The Carnegie Institution at Washington		[267]
XX.OBSERVATION
What to look for. The eye may not see what it does not expect to see. Lensesreveal worlds great and small otherwise unseen. Observers of the heavens and of seashore life. Collections aid discovery. Happy accidentsapplied to profit. Popular beliefs may be based on truth. An engineer taught by a bank swallow		[279]
XXI.EXPERIMENT
Newton, Watt, Ericsson, Rowland, as boys were constructive. The passion formaking new things. Aid from imagination and trained dexterity. Edison tells how the phonograph was born. Telephonic messages recorded.Handwriting transmitted by electricity. How machines imitate hands. Originality in attack		[299]
XXII.AUTOMATICITY AND INITIATION
Self-acting devices abridge labor. Trigger effects in thelaboratory, the studio and the workshop. Automatic telephones. Equilibrium of the atmosphere may be easily upset		[329]
XXIII.SIMPLIFICATION
Simplicity always desirable, except when it costs too dear. Taking directinstead of roundabout paths. Omissions may be gainful. Classification and signaling simpler than ever before		[340]
XXIV.THEORIES HOW REACHED AND USED
Educated guessing. Weaving power. Imagination indispensable.The proving process. Theory gainfully directs both observation and experiment. Tyndall’s views. Discursiveness of ThomasYoung		[355]
XXV.THEORIZING CONTINUED
Analogies have value. Many principles may be reversed with profit. Thecontrary of an old method may be gainful. Judgment gives place to measurement, and then passes to new fields		[366]
XXVI.NEWTON, FARADAY AND BELL AT WORK
Newton, the supreme generalizer. Faraday, the master ofexperiment. Bell, the inventor of the telephone, transmits speech by a beam of light		[387]
XXVII.BESSEMER, CREATOR OF CHEAP STEEL. NOBEL, INVENTOR OF NEW EXPLOSIVES
Bessemer a man ofgolden ignorances. His boldness and versatility. The story of his steel process told by himself. Nobel’s heroic courage in failureand adversity. His triumph at last. Turns an accidental hint to great profit. Inventors to-day organized for attacks of new breadth andaudacity		[401]
XXVIII.COMPRESSED AIR
An aid to the miner, quarryman and sculptor. An actuator for pumps. Engravesglass and cleans castings. Dust and dirt removed by air exhaustion. Westinghouse air-brakes and signals		[417]
XXIX.CONCRETE AND ITS REINFORCEMENT
Pouring and ramming are easier and cheaper than cutting andcarving. Concrete for dwellings ensures comfort and safety from fire. Strengthened with steel it builds warehouses, factories and bridgesof new excellence		[429]
XXX.MOTIVE POWERS PRODUCED WITH NEW ECONOMY
Improvements in steam practice. Mechanical draft.Automatic stokers. Better boilers. Superheaters. Economical condensers. Steam turbines on land and sea		[446]
XXXI.MOTIVE POWERS, CONTINUED. HEATING SERVICES
Producer gas. Mond gas. Gas engines. Steam andgas engines compared. Diesel engine best heat motor of all. Gasoline motors. Alcohol engines. Steam and gas motors united. Heat and powerproduction together. District steam heating. Isolated plants. Electric traction. Gas for a service of heat, light and power		[457]
XXXII.A FEW SOCIAL ASPECTS OF INVENTION
Why cities gain at the expense of the country. Thefactory system. Small shops multiplied. Subdivided labor has passed due bounds and is being modified. Tendencies against centralizationand monopoly. Dwellings united for new services. Self-contained houses warmed from a center. The literature of invention and discovery aspurveyed in public libraries		[478]
INDEX[489]