The Mexican Empire at the period of its conquest by Cortes had arrived at a standard of civilisation comparable with that of those dynasties which immediately preceded the rule of the Ptolemies in Egypt. The government was an elective monarchy, but princes of the blood alone were eligible for royal honours. A complex system of jurisdiction prevailed, and a form of district and family government was in vogue which was somewhat similar to that of the Anglo-Saxons. In the arts a high state of perfection had been reached, and the Aztec craftsman appears to have been a step beyond the slavish conventionalism of the ancient Egyptian artist. In architecture the Mexicans were highly skilled, and their ability in this respect aroused the wonder of their Spanish conquerors, who, however, did not hesitate to raze to the ground the splendid edifices they professed so much to admire. As road-builders and constructors of aqueducts they chiefly excelled, and a perfect system of posts was established on each of the great highways of the empire. With the Aztecs the art of writing took the form of hieroglyphs, which in some ways resembled those of the ancient Egyptians; but they had not at the period of their conquest by Cortes evolved a more convenient, and cursive method, such as the hieratic or demotic scripts employed in the Nile valley. In astronomical science they were surprisingly advanced and exact. The system in use by them was wonderfully accurate. It is, however, quite erroneous to suppose that it has affinities with any Asiatic system. They divided the year into eighteen periods of twenty days each, adding five supplementary days, and providing for intercalation every half-century. Each month contained four weeks of five days each, and each of the months had a distinct name. That the Aztecs were possessed of exact astronomical instruments cannot be proved; but in the thirteenth plate of Dupaix's _Monuments_, (Part II.) there is a representation of a man holding to his face an instrument which might or might not be a telescope.[2] The astronomical dial was certainly in use among them, and astrology, and divination in its every shape were frequently resorted to. In the manual arts the Aztecs were far advanced. Papermaking was in a moderate state of perfection, and the dyeing, weaving, and spinning of cotton were crafts in which they excelled. Feather-work of supreme beauty was a staple article of manufacture, but in the metallic arts the absence of iron had to be compensated for by an alloy of copper, siliceous powder, and tin--an admixture by the use of which the hardest granite was cut and shaped, and the most beautiful gold and silver ornaments fashioned. Sharp tools were also made from obsidian, and in the barbers' shops of the city of Mexico razors of the same stone were in use.