458 [Senate 



withstanding this great variety of stock, perhaps it is not generally- 

 known that there is but one kind of clay, and it is, perhaps, seldom 

 that the stock contains one-half, or perhaps, one-third of this article, 

 and it is frequently the case there is but simply enough to operate as 

 a cement for other substances ; and I have known brick made out of 

 stock which a practical chemist informed me contained but one-thir- 

 tieth part of clay, but the bricks were not of good quality. It would 

 occupy too much room, and be of little practical benefit to go into 

 nice chemical details of all the different ingredients composing the 

 various stock for manufacturing brick, and I shall confine myself to a 

 few facts. 



Most persons judge of the quality of brick by their color, red be- 

 ing supposed to be of good quality. Red is the color most fancied 

 for fronts ; hence, stock that will color a beautiful red, is valuable 

 for making what are called pressed brick, which are used for fronts of 

 buildings ; but the color has very little to do with the quality, for 

 strength or durability ; and the manufacture has as little to do with 

 the color, as that has to do with the strength and durability. It is 

 the prevailing mineral in the stock, that gives the color ; when this 

 is oxide of iron, the brick will be a beautiful red ; but if this mine- 

 ral be absent, and magnesia prevail, it will have a whitish color ; and 

 when copper prevails, a cream color, — the color varying according 

 to the combinations of these and other minerals. 



No regular system has been, as yet, adopted for the manufacture of 

 brick. Brick-makers in different sections, operating in entirely dif- 

 ferent ways ; so much so, that a. skillful workman in one place, 

 would be no better than an inexperienced hand, in another, — espe- 

 cially in that important part of the business, molding. In one sec- 

 tion, the stock is tempered entirely by the physical labor of man, 

 with a spade or shovel ; in another, by the tramping of oxen, and 

 sometimes horses are used ; and in another with what is sometimes 

 called a hedge-hog, — a round log with wooden pins, to the outer end 

 of which are attached oxen or horses, by which means it is made to 

 revolve round horizontally over the stock, in a circular pit ; then, 

 again, some use a large iron wheel, which is made to revolve on an 

 iron shaft, in such manner as to run alternately from the outside to 

 the centre, and back. But what is called the tub mill, or square tub 

 with an upright shaft placed in the centre, in which are placed knives 

 that pass through the stock, and a shaft or lever attached to the top, 

 to which is attached a horse, is more generally in use, than any 

 machinery for tempering mortar. The methods of molding, or 

 forming the mortar into bricks in molds, are nearly as variable as 

 that of tempering the stock. Formerly, the most common means 

 used to make brick deliver from the mold, was water; but now, 

 sand is more generally used ; molding in water is entirely a diffe- 

 rent business from molding in sand, — and one skilled in the former 

 mode, could not mold in sand without first learning. Then again, 

 the manner of molding in sand at the north, is different from that 

 practiced at the south ; and the facility with which the work is done, 



