the Caucasian Mountains, which have given a name to the most intellectual variety of the human race.

41. Mount Ararat, which is a little South of the 40th parallel, is very nearly the exact latitude of Philadelphia.

42. The dark spot on Mount Ararat, the Ark. This is delineated as marking the locality of the patriarchal civilization, the vale of Shinar, the sources of the Euphrates and the Tigris, the fountains of sacred history.

43. The Vine. 44. The Colliseum of Rome.

45. The Horse. 46. The Apple tree. 47. Wheat.

48. The Pumpkin. 49. The Ox.

50. The Oak tree. 51. Sheep. 52. Barley.

53. The Church of Notre Dame, Paris.

54. Ocean and emblems of Commerce.

55. St. Paul's, London. 56. The Roe Buck.

57. The Potatoe plant, emblem of lat. Dublin.

58. Rye. 59. The castled hill in the distance, Edinburg. 60. The brown Russian Bear, lat. Moscow.

61. Fir trees. 62. Flax. 63. Hemp. 64. Turnips.

65. Oats, the most Northern of the Cereal grains.

66. The Birch tree. 67. The Larch.

68. The Moose Deer.

69. Hunter and dog after wild fowl, the wild goose.

70. Laplander and Reindeer.

71. Esquimaux and dogs. 72. Icebergs.

73. Polar Bear, the last animal at the North.

74. Man, who for short excursions penetrates farthest but gladly hastens back from the uninhabitable North. 75. Icebergs.

Ocean Scene, commencing at the Equator.

The moderately elevated Land, N. Lat. 3, is Cape de Norte, the mouth of the Amazon, East coast of South America.

The Mean Temperatures of warm parallels of the ocean are usually several degrees cooler than on land, in similar parallels.

The Mountain, lat. 7, is Adams' Peak, Isle of Ceylon, lat. 7°6', North.

The ship, lat. 10, may be considered as a homeward bound East Indiaman.

The Palmtree island, lat. 13, is one of the horse-shoe shaped coral islands of the Tropics. The little boat is intended for a Malay prow.

At lat. 15 to 20, is represented a ship under close reefed topsails, and a Typhoon or Hurricane, one of those exaggerations of our thunder storms, which, though not of great extent, are very severe, and of which perhaps hundreds are at all times roaring over the tropical latitudes of the ocean. Thunder storms are less frequent in the temperate latitudes and very rarely occur in the North.

Lat 23°9', is the Moro Castle at the Havana, which, as it is within twenty miles of the Tropic of Cancer, is used as a landmark of the Tropic.

The vessel lat. 25, is intended for a Baltimore clipperbuilt West India trading schooner.

The Mountain in the distance, lat. 28°13', is the peak of Teneriffe.

The pagoda is intended for the pagoda of Nankin, China, lat. 33°30'.

Lat. 36°5', is the rock of Gibraltar, with a Spanish boat in the foreground.

Lat. 38, a Greek felucca, the promontory of Sunium, with the ruins of the Temple of Minerva in the distance. Lat. 40, an Italian polacre, Mount Vesuvius in the distance.

Lat. 43, a Genoese vessel, indicates the home of Christopher Columbus.

Lat. 44, may represent the largest American Man-ofWar, the Pennsylvania.

Lat. 46, is the Great Western, the celebrated English steam-packet ship, from Bristol to New York.

Lat. 48, the sail on the horizon may be a Dutch vessel. Lat. 49, a French Frigate.

Lat. 50°8', the Eddystone Lighthouse, Lands-End of Engand, and a ship in a storm.

Lat. 53, on the horizon a Danish vessel.

Lat. 55, a Swedish vessel.

Lat. 57, a Prussian vessel.

Lat. 57°38', the Skaw at the entrance of the Cattegat, mouth of the Baltic.

Lat. 59, a Russian vessel.

Lat. 60, a Norwegian vessel.

Lat. 62, an American Whale ship.

Icebergs.

Lat. 63, Mount Hecla in Iceland, an Esquimaux boat, a Polar bear on a field of ice.

Icebergs.

The Aurora Borealis.

CHAPTER V.

We are, to our own observation, in the middle of the universe. Our knowledge of what is around us must begin from a point of which we are the centre. Our own daily and yearly relations to the sun are the seasons of our own landscape; those of the different latitudes constitute the climates of the globe we inhabit. These are perhaps the first and most obvious and impressive lessons in terrestrial astronomy. To explain these is the purpose of the Dial of the Seasons. The Dial is an illustration of the sunlight as it falls on our planet.

GENERALIZATION OF THE LAWS OF LIGHT.

From the preliminary consideration of the sunlight, as it falls on our own planet, it is natural to pass to the illustration of the laws of light, as it expands in the universe, and to the generalization of the laws of light.

Light is subtle and ethereal; men differ as regards its na ture. One thing is certain—the absence of light is darkness; it is the cause of which seeing is the effect. Without it, our noble sense of sight would be useless.

Light is a subject of unbounded extent and interestequally worthy of our investigation, whether considered in the grand or the useful, the illimitable or the infinitely minute developments of nature continually occurring around us; or in the wonderful adaptation and exquisite susceptibilities of those organs of vision which receive its most minute and feeblest impressions, and by some inscrutable association with the operations of the mind, render them immediately subservient to the simplest wants of existence, or the most exalted efforts of intellect.

The present chapter chiefly considers light as it radiates. in the universe.

From the properties, nature, and existence of light in our solar system, we derive laws which we shall attempt to illustrate, and which enable us to contemplate it as the omnipresent traverser of infinite space-pouring from its eternal reservoirs into a theatre where, only, its nature could be illustrated, and which it alone could illumine.

This sublimated ethereal substance, according to the inspired Hebrew historian, was spoken into existence by the first fiat of the Eternal, and originated in the incipient act of creative energy on rude and darkling chaos. Holding an intermediate relation to matter and immaterial existence, and triumphing in the inconceivable velocity and infinite extent

of its emanations over time and space, it is a sort of angelic messenger from the throne of the Omnipotent to the boundlessness of universal creation.

It is certainly the most magnificent prototype which physical creation affords of the omnipresence of Deity, and of the unity of that self-existent universal energy, which, while it "spreads undivided," and "operates unspent” in the worlds of matter and of mind, is continually revealing to intelligent creation the infinity and benignity of creation's Author.

Mankind, in the earliest ages, as by universal consent, had invested light with the attributes of divinity. The most barbarous nations of both hemispheres, as well as those on the Delta of the Nile, the plains of Chaldea, the mountains of the Caucasus, and the shores of the Ægean and the Adriatic, worshipped the sun as a benignant deity from their earliest traditions.

The planets, and the starry vault beyond them, as their periodical revolutions marked the lapse of time, and the returning seasons of seed-time and of harvest, to the transient generations of men, could not but inspire a degree of sublimity and of devotional sentiment among the rude wanderers on the banks of the Missouri, the Niger and the Ganges, as well as among those nations whose mythology and whose rapturous poetry had taught them to view the constellations of Heaven as no other than the resting-places of their translated heroes, and the happy abodes of the immortals.

The examination of the physical properties of Light was, however, an investigation but little known to the ancients, and our present knowledge has been a gradual consummation of the experience of many ages.

Of the philosophers of antiquity, Plato was the first who has left us any observations on the subject. He considered vision to be occasioned by minute particles, continually fly