rank among all known orders of architecture, is the execution of their mosaic relievos, very different from plain mosaic, and consequently requiring more ingenious combination and greater art and labor. They are inlaid on the surface of the wall, and their duration is owing to the method of fixing the prepared stones into the stone surface, which made their union with it perfect." Figure 33, taken from Charnay's photograph, shows part of the mosaic decoration on a wall of one of the great edifices at Mitla.

The general character of the architecture and masonry is much like that seen in the structures at Palenque, but the finish of the workmanship appears to have been more artistic and admirable. These ruins are remarkable among those of the country where they are found. All who have seen them speak much as Dupaix speaks of the perfection of the masonry, the admirable design and finish of the work, and the beauty of the decorations. Their beauty, says M. Charnay, can be matched only by the monuments of Greece and Rome in their best days.. One fact presented by some of the edifices at Mitla has a certain degree of historical significance. There ap-, pears to be evidence that they were occupied at some period by people less advanced in civilization than their builders. M. Charnay, describing one of them, points out this fact. He says of the structure:

"It is a bewildering maze of courts and buildings, with facings ornamented with mosaics in relief of the purest design; but under the projections are found traces of paintings wholly primitive in style, in which the right F

line is not even respected. These are rude figures of idols, and meandering lines that have no significance. Similar paintings appear, with the same imperfection, on every great edifice, in places which have allowed them shelter against the ravages of time. These rude designs, associated with palaces so correct in architecture, and so ornamented with panels of mosaic of such marvelous workmanship, put strange thoughts in the mind. To find the explanation of this phenomenon, must we not suppose these palaces were occupied by a race less advanced in civilization than their first builders ?"

Two miles or more away from the great edifices here mentioned, toward the west, is the "Castle of Mitla." It was built on the summit of an isolated and precipitous hill of rock, which is accessible only on the east side. The whole leveled summit of this hill is inclosed by a solid wall of hewn stone twenty-one feet thick and eighteen feet high. This wall has salient and retiring angles, with curtains. interposed. On the east side it is flanked by double walls. Within the inclosure are the remains of several small buildings. The field of these ruins was very large three hundred years ago. At that time it may have included this castle.

AN ASTRONOMICAL MONUMENT.

In this part of Mexico Captain Dupaix examined a peculiar ruin, of which he gave the following account: "Near the road from the village of Tlalmanalco to that called Mecamecan, about three miles east of the latter, there is an isolated granite rock, which was artificially

formed into a kind of pyramid with six hewn steps facing the east. The summit of this structure is a platform, or horizontal plane, well adapted to observation of the stars on every side of the hemisphere. It is almost demonstrable that this very ancient monument was exclusively devoted to astronomical observations, for on the south side of the rock are sculptured several hieroglyphical figures having relation to astronomy. The most striking figure in the group is that of a man in profile, standing erect, and directing his view to the rising stars in the sky. He holds to his eye a tube or optical instrument. Below his feet is a frieze divided into six compartments, with as many celestial signs carved on its surface." It has been already stated that finely-wrought "telescopic tubes" have been found among remains of the Mound-Builders. They were used, it seems, by the ancient people of Mexico and Central America, and they were known also in ancient Peru, where a silver figure. of a man in the act of using such a tube has been discovered in one of the old tombs.

RUINS FARTHER SOUTH.

Old ruins, of which but little is known, exist in Guatemala, Honduras, San Salvador, and the more southern portion of Central America. Mr. Squier, who tells us more of them than any other explorer, says, "I heard of remains and monuments in Honduras and San Salvador equal to those of Copan in extent and interest." He mentions the ruins of Opico, near San Vincente, in San Salvador, which "cover nearly two square miles, and