He must be knowing in History, and be able to give a reason for the greatest part of the Ornaments of Architecture which are founded upon History. For Example, if instead of Pillars he support the Floors of the House with the figures of Women, which are called _Cariatides_, he ought to know that the _Greeks_ invented these Figures to let Posterity know the Victories they obtained over the _Cariens_, whose Wives they made Captives, and put their Images in their Buildings. It's necessary likewise, that he be instructed in the Precepts of Moral Philosophy; for he ought to have a great Soul, and be bold without Arrogance, just, faithful, and totally exempt from Avarice. [Sidenote: _Lib. 1. Chap. 11._] The Architect also ought to have a great Docility which may hinder him from neglecting the advice that is given him, not only by the meanest Artist, but also by those that understand nothing of Architecture; for not only Architects, but all the World must judge of his Works. [Sidenote: _Lib. 1. Chap. 2._] Natural Philosophy is likewise necessary for him for to discover what are the Causes of many things which he must put a remedy to. He ought also to know something of _Physick_, to know the qualities of the Air, which makes Places Healthful and Habitable, or the quite contrary. He should not be ignorant of the Laws and the Customs of Places for the Building of Partition Walls, for prospect and for the conveying of Waters and Sewers. He ought to know _Astronomy_, that he may be able to make all sorts of Dials. It was necessary among the Ancients, that an Architect should have skill in _Musick_ to make and order _Catapults_ and other Machines of War, which were strung with strings made of Guts, whose sound they were to observe, that they might judge of the strength and stiffness of the Beams which were bended with those Strings. _Musick_ was also necessary in those days for the placing musically Vessels of Brass in the Theatres, as we have said before. ART. III. _What are the Parts of Architecture._ There are Three Things which ought to meet in every Fabrick, _viz._ _Solidity_, _Convenience_ and _Beauty_, which Architecture gives them; by the due ordering and disposition of all the Parts that compose the Edifice, and which she rules by a just Proportion, having regard to a true _Decorum_, and well regulated _Oeconomy_; from whence it follows, that Architecture has Eight Parts, _viz._ _Solidity_, _Convenience_, _Beauty_, _Order_, _Disposition_, _Decorum_, _Oeconomy_. _Solidity_ depends upon the goodness of the Foundation, choice of Materials, and the right use of them; which ought to be with a due order, disposition and convenient Proportion of all Parts together, and of one in respect of another. _Convenience_ likewise consists in the ordering and disposition, which is so good that nothing hinders the use of any part of the Edifice. _Beauty_ consists in the excellent and agreeable form, and the just proportion of all its parts.