locality, "A good hat and a good pair of shoes is all that cob wants." The pair of shoes here meant is a stone foundation such as I have described in the Persian houses—that is, to protect the lower part of the wall; and the hat is a sufficient amount of thatch, or covering, to the top of the wall to save it from the influence of rain. With such conditions, I believe that mud walls in Devon, even in our own damp climate, have stood for long periods of time.
The sloping jambs of doors and windows are peculiar to many old styles of architecture, such as the early Greek and Etruscan. Theories of origin for this have been often suggested, but we have no difficulty in accounting for them, if we suppose that the narrowness above was a form, and the natural result of the sloping walls of mud.
I have already explained how builders in mud—and which is well exemplified in Persia—construct their walls with a broad base, to give solidity below, and with a marked batter upward to reduce the weight above. It has been suggested—and, I think, with every reason in its favor—that this explains the very marked slope of the perpendicular lines of the Egyptian pylons. All the authorities agree in stating that in the old temples the outer wall forming the temenos of temples of Egypt was made of crude brick, and as the pylon was the gate through this wall in front of the temple, the great probability of its being constructed of the same material is obvious.
When I had seen village after village in Persia with vaulted or domed roofs, and learned that such roofs could be formed without centers, the idea immediately suggested itself that these methods of building had existed from the most primitive times. While the necessity for wooden centerings for building vaults and domes was believed in, we never could have credited an early state of civilization with this invention. Let this assumption regarding centers be removed, and the whole problem is changed. The earlier workers in mud or clay could not have been long in discovering how to spread their material over the space inclosed by four walls. They would, no doubt, have begun at first with small spaces, and a very little experience would soon have enabled them to deal with greater. If any one considers the matter, I think he must arrive at the conclusion that mud must have been first used for a long period of time before burned brick came into existence; and now that we know how easy it is to produce a roof with the mud, there is no great improbability in the assumption that the vault or dome, as well as the arch, all date back to a period when that material alone was in use.
I have described the foundations of a mud wall, such as they are in Persia, formed of burned bricks or stones and lime; and also