904 Transactions of the American Institute. 



and retentiveness of water or damp. In England, the common bricks 

 absorb as much as a pint (or a pound) of water. Supposing the exter- 

 nal walls of an ordinary cottage to be one brick thick, and to consist 

 of 12,000 bricks, they will be capable of holding 1,500 gallons, or six 

 and a half tons, of water. To evaporate this amount of water would 

 require three tons of coal, well applied. The softer and more worka- 

 ble stones are of various degrees of absorbency, and appear to be 

 more retentive of moisture than common brick." 



The chilling sensation experienced on entering an unwarmed brick 

 house in winter is not suprising, when we consider that the walls 

 must be one mass of ice, making the air within the house still colder 

 than without. When it is further considered that Portland cement 

 stone is non-absorbent of moisture, it will not appear strange that 

 houses built of it are from eight to ten degrees warmer in winter than 

 houses built of brick. 



Resistance against Fire. 



To any one acquainted with the chemical composition of cement 

 stone, it must at once become evident that, with regard to its resistance 

 against fire, it ought to supersede most building stones. That this is 

 really the case, we learn from several reports before us, given on the 

 " Frear stone," which was used in the construction of several buildings 

 in Chicago, and which is essentially a cement stone. Merrill Ladd, Esq., 

 president of the Mutual Life Insurance Company of Chicago, writes 

 as follows : 



" In passing through the ' great fire] no signs of flaking, splitting, 

 or disintegration were perceptible, as was the case with all natural 

 stone (even granite) which was used in this city. I will say, in con- 

 clusion, that I believe it to be the best material that can be used for 

 building, where strength, solidity and protection against fire are 

 desired." 



Also Professor McChesne}' , the geologist, says : 



" I examined its condition just after our great fire, where it had 

 been exposed to as severe tests as any building material in this city ; 

 it was neither cracked nor scaled off by the great heat so badly as the 

 real stone used in this city ; and, on examination closely, the heat 

 had not penetrated but about two inches in any instance, from w T hich 

 I conclude it might be used to advantage in the construction of fire- 

 proof vaults." 



I would gladly add other testimonials, if I did not fear that I had 

 already occupied more space than is usually assigned to such papers. 



