6. ZODIACAL LIGHT.

This is one of the most extensive phenomena in the solar system; but of such feeble light as to be barely visible in the darkest nights.

It is disposed somewhat excentrically about the Sun, and is flattened out nearly in the plane of the ecliptic. In that plane it has a radius of about 90 millions of miles, and at right angles to that plane, about 20 millions of miles.

Occasionally it reaches as far as the Earth's orbit, and the separate particles of it are then distinguished as the so called "shooting stars."

They revolve about the Sun as planetary bodies, and are

recognised by the enormous velocity which they are observed to have, and which nothing but revolving motion at that distance from the Sun could possibly give. (See PLANETARY TABLE).

On their approaching nearer to the Earth still, they occasionally fall upon it, as "meteoric" stones; and are always found to have a very remarkable chemical composition. They become inflamed and explode on entering our atmosphere; having previously shone only by light reflected from the Sun, like the Moon and all the planets.

On the whole, the Zodiacal Light is supposed to be a remnant of the great nebulous atmosphere about the Sun, out of which the planets may have been formed by condensation.

PART III-BODIES CIRCULATING ABOUT THE PLANETS AS PRIMARIES.

ELEMENTS

OF

PHYSICAL AND CLASSICAL

GEOGRAPHY.

THE GEOGRAPHY

ОБ

THE ANCIENT WORLD,

IN SO FAR AS IT IS SUBSERVIENT
TO THE UNDERSTANDING AND ILLUSTRATION

OF THE CLASSICS.

I.

HISPANIA, Graece et Poetice IBERIA,
(SPAIN AND PORTUGAL)

WAS the name given by the Romans to a peninsula of quadrangular shape, in length and in breadth about 600 miles, which occupies the S. W. extremity of Europe, and is wholly contained within the lines of 36° and 44° N. latitude, and of 31° E., and 91° W. longitude.

PHYSICAL CHARACTERS OF THE PENINSULA.

An elevated ridge of Mountain and Table-land extends from N. to S., forming the water-shed of the country, and giving origin to all the great rivers, some of which find their way to the Mediterranean, and some to the Atlantic. To this crest, or backbone as it were of the peninsula, are attached, on the side facing the West, ranges of mountains and

B