This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1839. Excerpt: ... round it nearly fits the cavity of the pipe, and removes any deposit, or obstruction to its discharging end without difficulty. It seldom happens that a road can be continued for any great distance, without the necessity of constructing culverts for the conveyance of water under it, or bridges for passengers and carriages to pass over rivers or streams, and it may therefore be expected that something should be said on these subjects; but as their formation embraces principles of construction not yet treated of, we must defer any observations on these heads until these principles have been explained. CHAPTER VIII. ON BUILDING MATERIALS. Section I.--Of Stones and Bricks. 451. Under the general denomination of building materials are comprehended all the various substances made use of in the formation of buildings, machinery, and constructions of every kind; and the object of the present chapter is, to enumerate some of the principal of these, to point out what they are, how they are procured, and converted into such forms as will render them available; and that done, the succeeding chapter will investigate their value and forms, by an examination of their strength and durability, and the purposes to which each are particularly suitable. 452. Many of these materials are produced by nature in a state fit for immediate use, such as the several varieties of stone and timber; while others require operations of art and manufacture to render them available, of which bricks, lime, the metals, and many other things that might be mentioned, are examples. On this account these materials have been called natural and artificial, but this distinction is unnecessary; and in proceeding to describe them we shall, therefore, follow the order of their unity in preference to an...