ARRANGED ACCORDING TO MONTHS

SEPTEMBER.-Weather: Appearance and Names of Clouds; Blackboard
Record; Direction and Velocity of Wind; Excursions; Rain.
Plants: Aster; Black-eyed Susan; Butter and Eggs; Chicory
Ferns; Garden Nasturtium; Goldenrod; Ironweed; Jamestow
Weed; Morning Glory; Pond Lily; Sunflower; Thistle; Wi
Carrot.-Animals: Bee; Beetles; Cicada (Locust, or Harv
Fly); Dragon Fly; Fly; Locust (Grasshopper); Mosquito; Mc
and Butterflies (general); Tussock Moth.
OCTOBER.- Weather: Excursions; Records; Sun.-Plants: Floers
(continued). See list under September.-Fruits: Ailant 18;
Apple; Ash; Burdock; Chestnut; Maple; Stick-me-tig-
Animals: English Sparrow: Insects (continued). See list ader
September.

NOVEMBER. - Weather: Examination of October Record; Moon;
Temperature.-Plants: Buds; Bulbs; Falling Leaves; Fleshy
Roots.-Animals: Cocoons; Other Preparation for Winter; The
Pigeon.

DECEMBER.-Weather: Examination of November Record Record;
Snow; Stars.-Plants: Arbor Vita; Balsam Fir; Hemlock;
Holly; Mistletoe; Pine; Spruce. -Animals: Fish; Mussels;
Snail; Tadpole.

JANUARY.-Weather: Boiling; Condensation; Evaporation; Examina-
tion of December Record; Record.-Plants: Evergreens (con-
tinued). See list given under December; Germination.-Animals:
Beaks and Feet of Birds; Bones of Birds; Crow; Feathers;
Owl; Woodpecker.

FEBRUARY.-Weather: Clouds; Dew; Frost; Hail; Rain; Records;
Snow.-Plants: Germination (continued); Seed Food-supply.-
Animals: Chickadee ; Golden-crowned Kinglet; Snowbird; Winter

Wren.

MARCH.-Weather: Records.-Plants: Buds; Seed Food-supply (con-
tinued).-Animals: Blackbird; Bluebird; Earthworm; Excursions;
Migration; Robin.-Stones: Clay; Feldspar; Mica; Pebbles;
Quartz; Sand; Soil.

APRIL.-Ailanthus; Arbutus; Ash; Beech; Birches; Bloodroot;
Buckeyes; Buds; Cherry; Chestnut; Dogtooth Violet; Elms;
Excursions; Hepatica; Hickory; Horse-chestnut ; Linden ;
Locusts; Maples; Oaks; Poplars; Quaker Ladies; Spring
Beauty; Sycamore (Buttonwood); Violet; Walnut; Willows.-
Animals: Bees; Beetles; Butterflies; Moths.-Stones: Gneiss ;
Granite; Mica Schist.

MAY AND JUNE.-Plants: Apple; Buttercup; Chickweed: Clover;
Daisy; Dandelion; Ferns; Fungi; Jack-in-the-pulpit; Lichens;
Mosses; Sheep's Sorrel; Shepherd's Purse; Strawberry; Trees
(continued). See the list given under April.-Stones: Limestone;
Sandstone; Slates and Shales.

APPENDIX.

Adapted to the Elementary Stage of the South Kensington Syllabus, and suitable for the Junior University Local Examinations

London

MACMILLAN AND CO., LIMITED

NEW YORK: THE MACMILLAN COMPANY

166

PHYSIOGRAPHY FOR BEGINNERS

CHAP.

the east and west of this locality was made in the last chapter. Being able, however, to now regard the earth as a spinning globe, we are in a position to explain this difference more fully. Fig. 78 makes the matter very simple. The student must suppose himself in space looking down upon the north pole of the earth, which is situated at the intersection of the diameters of the circle representing the equator of the earth. The circle is divided into twenty-four equal parts, and hence the angle between any pair of radii will be 360 divided by 24, or 15 degrees.

FIG. 78.-To explain the different times at places east and west of Greenwich.

As the globe spins round each radius in turn occupies the position of that one marked " 12 noon." An observer in this position will see the sun in his highest position for the day, or on the meridian, that is, southing. The observer situated at the opposite end of the same diameter will be as far away from the sun as he can possibly be. Or, to take an example, at places longitude 180° it will be twelve o'clock midnight when it is twelve o'clock noon at Greenwich. When the sun is on the dian at Greenwich at places 90° W. and 90° E. it will be Mock in the morning and six o'clock in the evening (continu

Sandstone APPENDIX.

32

31

199

stem of the barometer shown in Fig. 95, the mercury column to its upper limit in the long tube, the air to its upper limit, which as will be seen, is a great distance from the surface of the earth. If for any reason the weight of the atmosphere becomes greater, the mercury will be pushed higher to preserve the balance; if it should become less, then similarly the amount of mercury which can be supported will be less, and so the height of the column of mercury is diminished.

The student will now understand why it is so necessary to remove all the air bubbles in Expt. 193. If this were not done, when the tube was inverted the enclosed air would rise through the mercury and take up a position in the top of the tube above the mercury. The reading would not then be thirty inches, for instead of measuring the whole pressure of the atmosphere, what we should really be measuring would be the difference between the pressure of the whole atmosphere and that of the air enclosed in the tube. In a properly constructed barometer, therefore, there is nothing above the mercury in the tube except a little mercury vapour.

An arrangement like that described constitutes a barometer, which we can define as an instrument for measuring the pressure exerted by the atmosphere.

.30

29

28

FIG. 95.-To explain the Principle of the Barometer.

§ EXPT. 194.-Procure a thick glass tube about thirty-six inches long and closed at one end. Fill the tube with mercury; place your thumb over the open end; invert the tube; place the open end in a cup of mercury and take away your thumb. A column of mercury will be supported in the tube by the pressure of the atmosphere. The distance between the top of the column and the surface of the mercury in the cup will be about thirty inches.

§ EXPT. 195.-Weigh the column of mercury sustained in the barometer

THIS book has been constructed to follow the annotated syllabus of Elementary Physiography published in the Directory just issued by the Department of Science and Art. Its distinctive features are:-(1) The large number of experiments described; (2) the liberal use of illustrations, many of them new; (3) summaries of the chief points in each chapter; (4) 250 questions on the subjects dealt with. The wide scope of the book will be seen from the following list of the subjects of the chapters:

Chapter I. Matter. II. Measurement of Space, Mass, and Density. III. Motion, Inertia, and Force. IV. The Mechanical Powers. V. Energy. VI. Heat and Temperature. VII. Radiation. VIII. The Chemical Composition of Matter. IX. Common Chemical Elements and Compounds. X. The Earth. XI. Rotation of the Earth, and Measurement of Time. XII. The Sea, the Earth's Revolution, and the Moon. XIII. The Atmosphere. XIV. Atmospheric Phenomena. XV. The Oceans. XVI. Currents in the Oceans. and Glaciers. XVIII. The Earth's Solid Crust, Igneous Rocks. XIX. Aqueous and Metamorphic Rocks. XX. Internal Forces acting on the Earth's Crust. XXI. Terrestrial Magnetism.

PRESS OPINIONS

XVII. Rivers

Educational News-"This is really an excellent text-book on the subject. . . . The value of the work as a practical text-book on the subject cannot be overestimated."

Royal College of Science Magazine-"Mr. Simmons' book should have a large circulation, and we recommend it both to those who will use it as a text-book, or as ground work for lectures and demonstrations."

Educational Times-"Mr. Simmons has evidently written his book with extraordinary care, and to read his chapters on 'Energy' is to be convinced that he is a teacher of very exceptional ability."

Academy "It is anything but a light task to undertake the explanation of the elementary principles of mechanics to persons whose mathematical knowledge is limited to arithmetic, yet Mr. Simmons has attempted it with great success.. A pupil-teacher who has mastered its contents and has performed the numerous experiments described, will never lack material for an object lesson."

Nature-"It may be stated at once that the book covers the syllabus in the most complete and satisfactory manner, and we have no hesitation in saying that teachers will find it to adequately meet their requirements as a class-book. The descriptions are clear and not too long, and great pains have evidently been taken to ensure accuracy in every section. One of the best features is the great prominence given, for the first time, we believe, to experimental illustrations of the subject, all those suggested in the syllabus having been incorporated, and others added to make a total of 216, all of which require but simple appliances."