206 ANNUAL OP SCIENTIFIC DISCOVERY. 



flaws and cracks, and is injured by damp and frost like terra cotta. 

 3. The silicious stone is rarely flawed in the kiln, but even if it is 

 the stone does not crack or the surface peel by exposure to damp 

 and frost, owing to the nature of the cement, which is, in fact, glass. 



A new process, however, has been recently discovered by Mr. Han- 

 some, which promises most valuable results. Heretofore, his artificial 

 stone, after its formation in a, plastic state, required about one month 

 to dry, and another to be kiln-burnt. Now, it seems, the plasticity is 

 superseded by stony hardness not only without either drying or kiln- 

 burning, but also in an hour or two's time ! The moulded or prepared 

 stone requires simply to be dipped into a solution, and the work is 

 done, even when tke stone has been one weighing a whole ton weight 

 or more. The solution consists of chloride of calcium ; or, as it is 

 more properly called when dissolved in water, muriate of lime. 

 When the moulded matter is dipped into this solution it is very soon 

 saturated with it, and a double decomposition takes place ; the lime 

 combines with the silica, forming a silicate of lime, and the muriatic 

 acid with the soda of the water-glass, forming common salt, which can 

 be removed by washing. To prove that by this process a coating of 

 hard -silicate of lime is actually formed, Mr. Ransome, in a public ex- 

 periment, made small blocks of various forms, in moulds, by mixing 

 loose sand with the fluid silicate of soda, and then dipping the mould 

 into the chloride of calcium ; when there came out almost instanta- 

 neously a perfectly compact, hard, and, to all appearance, a perfectly 

 durable solid. The stone thus formed has already been tried on a 

 somewhat extensive scale, and found to answer all requirements. At 

 the Great Exhibition of 1862, a mass of it, weighing ten tons, formed 

 the bed of a steam-engine ; and a four-inch cube has been found to 

 sustain a weight of thirty tons before crushing. 



At the meeting of the British Association, in 1862, Mr. Ransome, 

 at the conclusion of Prof. Austed's remarks, manufactured the stone 

 in the presence of the audience. It consists of any kind of mineral 

 fragments, sand, limestone, or clay, mixed into paste with fluid silicate 

 of soda (obtained by digesting flints in a boiler under high pressure 

 in alkali), and afterwards dipped into a solution of chloride of cal- 

 cium. The result is an almost immediate hardening of the pasty 

 mass, and the specimens constructed were in a few minutes handed 

 about the room. 



In a paper on the preservation of stone, recently read before the 

 London Architectural Association, Mr. A. II. Church noticed the 

 curious effect produced on stones by the efflorescence of sulphate of 

 soda or sulphate of magnesia upon their surface. The formation of 

 such salts is actually favored by some of the so-called preservative 

 processes ; and it is remarkable to note upon the summit of each 

 hair-like crystal a minute fragment of stone torn off and carried for- 

 ward by the force of the crystallization. Another singular phenom- 

 enon was described as occurring when a strong solution of silica in 

 water is applied to chalk or any soft limestone. The silica glutinizes 

 on the surface ; the film thus formed separates into small scales, and 

 as these fall off, it will be noticed that their under surfaces are cov- 

 ered with minute adherent particles of the stone or chalk. 



