Cairns are conical heaps of loose stones frequently found on the top of hills or artificial tumuli ; the term is derived by Mr. Roland from two Ilebrew words, signifying coped heaps. On these are supposed to have been kindled fires, at which certain religious ceremonies took place, such as that mentioned as being observed by the Israelites in making their children pass through the fire. in imitation of their heathen neighbours ; thus connecting the customs of the British Druids with those of Asia and l'hcenivia. From these Druidical practices may have arisen perchance the ordeal by fire of later times.
At New Grange. near Drogheda. Ireland. is a curious sepulchral pyramid of stone, formed of pebble stones, the weight of the solid contents of which amounted to no less than one hundred and eighty-nine thousand tons. The plan of this monument is curvilinear, and covers about two acres of ground, and is surrounded by a number of large unhewn stones, rising about seven feet above the ground ; the height of the pyramid is calculated at seventy feet. A great number of stones, removed tbr paving and other purposes, led to the discovery of a passage leading into an interior vaulted apartment. This passage began about forty feet within the body of the work, and is entirely composed of large flag stones; its length is sixty-one feet, the width three feet, and the height varies from two to nine feet. This passage leads into an octangular vaulted apartment, whose diameter is seventeen feet, and its height twenty ; the vault or dome is remarkable as being composed of overlapping horizontal stones, the upper ones projecting inwardly beyond the lower, sustained in their position by having a larger portion of each stone upon the one beneath it, than projects towards the interior; this construction is exactly similar to that of the tomb of .Agamemnon, or treasury of Atreus at
Nyeene. The side of this irregular octagon immediately opposite the entrance, is formed into a niche, as are also two sides at the right and left, similar to the erections called kist-vaens, the last two containing each a roek-bason. This building is, we believe, the only one of its kind existing in Britain.
We have not included the barrows or tumuli in the list of monuments to be considered, simply because they can scarcely be considered to have :my great connection with Architecture, lint as they are closely allied to the structure: we have been considering, we ought not to pass them without notice. They are were mounds of earth, of v.trious shapes, raised, as is supposed, over the graves of men of rank, and are found in great, numbers in the neighbourhood of the larger monuments : some of them are of shape, raised like coped tombs, some triangular, sotne circular :1114I ova], Of which again some are convex, some concave. Some are of the shape of bowls, and some of bells, while others are of a conical form ; occasionally two are formed together, and are called twin-barrows, but more frequently they are seen separate. Nary of them have been opened, and are found to contain not only human remains, hut also spear-heads and other implements of war, besides articles of domestic use, such as earthen vessels and the like. Their contents deter mine as well their use, as the date of their