1. Celtic or Druidical remains. 2. The Monuments of Egypt. 3. Asiatic architecture. 4. Greece. 5. Etruria and Rome. 6. The Early Christian style. 7. The Byzantine style. 8. Mahometan architecture. 9. The Romanesque style. 10. Gothic architecture. 11. The Renaissance. I. CELTIC OR DRUIDICAL REMAINS. The Celtic race has left enduring marks of its power in the numerous monuments which are found in various parts of Great Britain, France, Germany, and Spain, and scattered through adjacent countries. These consist of collections of huge uncarved boulders, arranged in geometrical lines, and often found in the centre of vast plains, far removed from quarry or mountain-side. The more common forms are called “menhirs or peulvans,” signifying in Celtic “long stones.” These are either found separately or ranged in long parallel lines. The most remarkable examples are at Carnac, in Brittany, where there are twelve hundred of these huge stones, varying from three to eighteen feet in height, ranged in eleven rows, leading to a semicircular enclosure. What purpose they served, and whether of a religious or civil character, has not been conclusively determined. Some consider that they served to mark the burial-spot of the Druids; others that they were landmarks or emblems of victory. To another class belong the so-called Rocking Stones, which consist of two immense blocks of rock, placed one upon the other, and either balanced so exactly that the slightest touch will suffice to shake them, or pivoted so as to revolve. There are examples at Tenanville, near Cherbourg, in the north of France, and in Sussex, England. One of these, called the “Great upon Little,” is estimated to weigh a million pounds. Batissier considers them to have been erected by the priests, either to strike terror and wonder into the hearts of the people, whom they sought to hold in subjection, or as emblems of the world suspended in the air. We know that they have existed from remote ages, as mention is made of their antiquity by Pliny and Ptolemy. Trilitha, or lichavens, are formed with three stones, two vertical and one horizontal resting upon the others, in the shape of a rude gateway. This is what they were probably intended for, though it has been suggested that they were used for altars. Similar to these are the dolmens, or table-stones, consisting of one large flat boulder supported by several smaller ones. Their upper surfaces, as a rule, have channels cut in them, which are generally believed to have been receptacles for the blood of victims sacrificed upon them, and some are even hollowed out in the shape of the human body. The Merchants’ Tables, at Lochmariaker, are the most noted among the many that still exist.