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In hot countries bricks are often used which have simply been dried in the sun in this way. But these sun-dried bricks will not stand much rain: the water soaks into them, and they once more become lumps of soft clay.
在炎熱的地區，以前經常把磚直接在太陽底下曬干。但是用太陽曬干的磚經不住水，水會滲進磚里，磚就又變回了軟軟的粘土塊兒。
The reason of this is that there is not only water in the pores of the clay, there is also water united with the clay itself, and this water can only be got rid of by the strong heat of a fire. So the bricks, after being dried in the air, are placed in a kiln. Fires are lighted beneath the kiln, and the bricks are baked or burned in it for some time.
這是因為，不只有粘土的孔洞里才有水，還有跟粘土融合在一起的水，這種水，只有用火焰的高熱才能去掉。所以，在空氣中晾干之后，磚坯就運進了磚窯，在磚窯底下燒起火來，把磚坯烤上或燒上一段時間。
Most bricks turn red when burnt. That is owing to the fact that the clay from which they were made contained a very little iron, and the burning changed this iron into iron-rust, which is of a red colour.
大多數磚在燒過以后，都會變成紅色。這種變化的原因是，磚的原料——粘土含有很少的鐵，燒磚的過程，把這些鐵變成了鐵銹，鐵銹是紅色的。
Bricks will stand a great heat without melting, especially those made from a kind of clay which is called fire-clay. Such bricks are called fire-bricks, and they are used for the backs and sides of fire-places, and for building furnaces in which metals are to be melted.
磚可以承受很高的溫度而不熔化，特別是那些用“耐火粘土”做的磚。這樣的磚就叫做“耐火磚”，用來做壁爐的后面和兩個側面，還用來做熔化金屬的熔爐。
