Part 1 (1/2)

How it Works

by Archibald Williams

PREFACE

How does it work? This question has been put toand old that I have at last decided to answer it in such a er public than that hich I have personal acquaintance may be able to satisfy the many of the mechanisms met with in everyday life

In order to include steaht, and a variety of detached mechanisms which cannot be classified under any one of these heads, within the coes, I have to be content with a comparatively brief treatment of each subject

This brevity has in turn compelled me to deal with principles rather than with detailed descriptions of individual devices--though in several cases recognized types are examined The reader will look in vain for accounts of the Yerkes telescope, of the latest thing in est loco the essential nature of _all_ telescopes, ines so far as they are at present developed, which I think reater ultimate profit to the uninitiated

While careful to avoid puzzling the reader by the use of y I consider that the parts of a iven their technical names wherever possible To preventthe letterpress have words as well as letters written on them This course also obviates the wearisoraures

I rams of this book, that they are purposely so to the canons of professional draughtsmanshi+p Where advisable, a part of a erated to show its details

As a rule solid black has been preferred to fine shading in sectional drawings, and all unnecessary lines are ohts the two hundred or ans of the body--the eye, the ear, the larynx, and the heart--are noticed in appropriate places The eye is compared with the camera, the larynx with a reed pipe, the heart with a pump, while the ear fitly opens the chapter on acoustics The reader who is unacquainted with physiology will thus be enabled to appreciate the better these marvellous devices, far more marvellous, by reason of their absolutely automatic action, than any creation of human hands

AW

UPLANDS, STOKE POGES, BUCKS

HOW IT WORKS

Chapter I

THE STEAM-ENGINE

What is steay of steam--The boiler--The circulation of water in a boiler--The enclosed furnace--The multitubular boiler--Fire-tube boilers--Other types of boilers--Aids to coe--The steae--The water supply to a boiler

WHAT IS STEAM?

If ice be heated above 32 Fahrenheit, its molecules lose their cohesion, and move freely round one another--the ice is turned into water Heat water above 212 Fahrenheit, and the molecules exhibit a violentsunshi+ne, separate and dart to and fro If confined in an air-tight vessel, the hts curtailed, and beat ainst their prison walls, so that every square inch of the vessel is subjected to a rising pressure We may compare the action of the steaun at a plate reater would be the continuous co

THE MECHANICAL ENERGY OF STEAM

If steaht but freely- piston, it will bombard the walls of the cylinder and the piston; and if the united push of the reater than the resistance on the other side opposing its ot their liberty, the orously The pressure on the piston decreases as it inal position against the force of the steam, the molecular activity--that is, pressure--would be restored We are here assuh the cylinder or piston and been radiated into the air; for any loss of heat y

THE BOILER

The combustion of fuel in a furnace causes the walls of the furnace to become _hot_, whichthe walls are thrown into violent agitation If the walls are what are called ”good conductors” of heat, they will trans substance In the case of the ordinary house stove this is the air, which itself is agitated, or groarm A steam-boiler has the furnace walls surrounded by water, and its function is to transh the furnace plates to the water until the point is reached when steaenerates At atmospheric pressure--that is, if not confined in any way--steam would fill 1,610 times the space which its molecules occupied in their watery formation If we seal up the boiler so that no escape is possible for the steam molecules, their motion becomes more andon the walls of the boiler

There is theoretically no limit to which the pressure y is transe quantities we reat heat in proportion to its weight, is readily procured, and cheap

Coal fulfils all these conditions Of the 800 hout the world, 400 million tons are burnt in the furnaces of steah to withstand her pressures than that at which it is worked; (2) so designed as to burn its fuel to the greatest advantage