eaiCK MAKINU*. 1 J 9 



BRICK MAKING. 



The following article is from the Edinburgh Enci/clopedia. It 

 contains some facts which are not generally known by brick- 

 makers, and some historical information interesting to every one. 



The art of brick making consists chiefly in the preparing and 

 tempering of the clay, and in the burning of the bricks ; and as the 

 quality of the ware depends very much upon the right performance 

 of these operations, we shall present our readers with a short sketch 

 of the general process of this manufacture. The earth proper for 

 making bricks is of ax^layey loam, neither abounding too much in 

 argillaceous matter, which causes it to shrink in the drying, nor in 

 sand, which renders the ware heavy and brittle. As the earth, be- 

 fore it is wrought, is generally brittle and full of extraneous matter, 

 it should be dug two or three years before it is used, that, by being 

 exposed to the action of tlie atmosphere, it may be suOiciently mel- 

 lo^wed and pulverised, and thus facilitate the operation of temper- 

 ing. At any rate, it should always have one winter's frost ; but 

 the longer it lies exposed, and tlie more it is turned over and 

 wrought with the spade, the better will be the bricks. 



The tempering of the clay is performed by the treading of men 

 or oxen, and in some places by means of a clay-mill. If the ope- 

 ration be performed by treading, which is the common way, the 

 earth is thrown into shallow pits, where it is wrought and incorpo- 

 rated together until it is formed into a homogeneous paste, which 

 is facilitated by adding now and then small quantities of water ; 

 but the less water that is used, the substance of the clay will be 

 more tough and gluey, and consequently the bricks will be smooth- 

 er and more solid. This operation is the most laborious part of 

 the process ; but it is of essential importance, and therefore ought 

 to be done well ; for it is to the negligence of (he manufacturers in 

 this respect, tiiat we are to attiibute the bad quality of our modern 

 bricks, which are often light and spongy, and full of cracks. 

 Whereas, if the clay be properly tempered, they are hard, ponde- 

 rous, and durable ; much stronger and better lilted for every kind 

 of building, than those made in the common way. This will ap- 

 pear very evident from the following experiment of M. Gallon, 

 Having taken a quantity of brick-earth tempered in the usual way, 

 he let it remain exposed to the air for seven hours, and then caused 

 it to be moistened and beaten for the space of half an hour: the 

 next morning the operation was repeated ; and in the afternoon 

 the clay was again beaten for fifteen minutes more ; making the 

 whole additional labor an hour and a quarter. The bricks made 

 of this earth, being dried in the air for thirteen days, and burned 

 along with the rest without any particular precautions, were found 

 to be not onlv heavier than common bricks, but also very dilferent 

 in strength ; for on placing their centre on a sharp edge, and load- 

 ing both the ends, Mr. Gallon found, that while it took a weight 

 of G§ lb. at each end to break them, other bricks wore broken by 



