ON MORTAR. 'fi|| 



V. 



On Mortars and Cements; Experiments that show (he Cohe- 

 sion which Lime contracts with Mineral ^ Vigetabie, or 

 Animal Substances; extracted from a Paper read to the 

 French Institute the 17 th of October, 1808, by B. G. 

 Sage*. 



A VING found, that an alkaline lixivisl gas was evolved Gas evolyed 

 from a mixture of three parts of sand and two of lime slacked ^^'^^ lime and 

 by immersion; and desirous of ascertaining;, whether the 

 products of the three kingdoms, minj^led in the same pro- 

 portions, would afford a similar gas ; Mr. Sage made a num- 

 ber of experiments, which taught him, that the force of co- .- , 

 hesion contracted by slacked lime was greater with metallic Metallic ox* > 



oxides in eeneral, than with any other substance. These »^^* strengthen 



" . / mortar, 



trials led him to new facts, which enabled him to discover 



mortars, or cements, at least as solid and impermeable as 



those made with the best puzzolana, which is of the greatest 



use, particularly in hydraulic structures. 



The work we announce points out also a prompt and easy 

 method of ascertaining the solidity and impermeability of 

 mortars or ceraents, which cannot but be highly interesting 

 to builders. 



We must not always judge of the goodness of a cement Mortar solid - 

 from its having acquired a great deal of coi^dity in the open '" *^^ air may. 

 air, for it frequently loses this in water, in which it diffuses water, 

 itself. Buildings made with such mortar soon tumble to pieces. 



The necessity of a minute division of the substances, thajl; '^^a^/i^ ♦ ,. 

 enter into a cement, cannot be insisted on too strongly. Rules for mak- 

 They should first be mixed together uniformly while dry ; jjj^^ good mor- 

 and they must not be drowned in water, which must be 

 added gradually, till the mixture is reduced to a soft paste, 



and of the other an inch and half: and those of the small scales, one half 



an inch, the other a quarter j we should get the proportions of a half, , ^^ 



A third, a fourth, and a sixth. Two rules, with joints mutually fitting 



each other, would give 16 di&erent proportions. If both edges be 



graduated, there must of course be a hole for a pivot at the extremity of 



each. C. ' 



• Journal des Mines, vol. XXVI, p. 471. The above appears to bm 

 the title of a pamphl«t, vrhi.h Mr. Sage has published separately. 



It. 



