INTENDED FOR THE

INSTRUCTION AND ENTERTAINMENT

OF

YOUNG PEOPLE:

IN WHICH

THE FIRST PRINCIPLES

OF

NATURAL AND EXPERIMENTAL

PHILOSOPHY

ARE FULLY EXPLAINED.

VOL. IV. OF PNEUMATICS.

Conversation, with the habit of explaining the meaning of words, and the
structure of common domestic implements, to children, is the sure and
effectual method of preparing the mind for the acquirement of science.

Edgeworth's Practical Education

BY THE REV. J. JOYCE.

A NEW EDITION,

WITH NUMEROUS CUTS, AND OTHER ADDITIONS
AND IMPROVEMENTS.

LONDON: PRINTED FOR BALDWIN AND CRADOCK;
AND R. HUNTER, ST. PAUL'S CHURCH-YARD,

C. Baldwin, Printer,

New Bridge street, London.

ΤΟ

VOL. IV.

Conversation

I. Of the Nature of Air: Wind, Air in Mo-
tion: how Fish swim...

II. Of the Air-pump; Dr. Darwin's Descrip-

tion; Barometer-guage; Resistance of

the Air; Philosophical Hammer.....

III. Of the Torricellian Experiment; Experi-

ments

IV. Of the Pressure of the Air: No such
principle as suction....

V. The same Subject continued: The Trans-

ferrer; Hemispherical Cups; Fountain

in Vacuo; Bottle broken by the Pres

sure of the Air; Mercury passes through

the Pores of Wood.

VII. Of the Elasticity of Air; Experiments;

VI. Of the Weight of Air.

Cupping.

VIII. Of the Compression of Air; Artificial

Fountains; Condensing Syringe and

common Squirt compared...

IX. Miscellaneous Experiments on the Air-

pump; why Smoke and Vapours ascend;

Lungs-glass; &c.....

X. Of the Air-gun and Sound; Air-guns ille-

gal; Magazine Wind-gun; Air, the

medium of Sound; Conducters of Sound;

Striking Experiment.....

Page

XI. Of Sound: Thunder; Gon-powder; Musi-

cal Chords; how far Sound can be heard ;

Velocity of Sound and Light; Uses to

which this Knowledge may be applied 96

XII. Of the Speaking Trumpet; Speaking

Figures, &c......

109

Conversation

XIII. Of the Echo: Line of Incidence and

Page

Reflection; Principle of the Echo.... 116

XIV. The same Subject continued; Echoes at

Glasgow, Brussels, Thornbury Castle,

Milan, &c.; Echo applied to measur-

ing inaccessible Distances; Whispering

Gallery at St. Paul's; Musical Glasses;

Different Tones depend upon the Num-

ber of Vibrations, and the Vibrating

Substance of the Instruments...

XV. Of the Winds; Smoke-jack, Trade

Winds, &c.; Experiments; Storms;

Velocity of Wind; Table....

XVI. Of the Steam-engine: when and by whom

invented; Mr. Watt's improvement.. 156

XVII. The same Subject continued....

XVIII. The same Subject, and Papin's Digester:

Whitbread's Brewery; Accidents by

Steam..

128

148

169

178

XIX. Of the Barometer: Fluctuation of the

Mercury; the Vernier; Rules for pre-

dicting the Changes of the Weather.. 189

XX. Application of the Barometer to the

measuring of Altitudes

200

XXI. Of the Thermometer; Fahrenheit's Scale 211

XXII. The same Subject; Wedgewood's Scale

of Heat; Fahrenheit and Reaumur's

Thermometer's compared............ 220

XXIII. Of the Pyrometer and Hygrometer.... 230

XXIV. Of the Rain-guage, and Rules for judging

of the Weather

APPENDIX.

Of Air, as a Vehicle of Heat and Moisture. Of

Rain-Dew-Meteoric Stones

242

253

CONVERSATION I.

OF THE NATURE OF AIR.

FATHER-CHARLES-EMMA.

FATHER. That branch of natural philosophy which is called Pneumatics, treats of the nature, weight, pressure, and spring of the air which we breathe, and of the several effects dependent upon these properties.

Charles. You told us, a few days ago, that the air, though to us invisible, is a fluid; but it surely differs very much from those fluids which you conversed upon when treating of hydrostatics.