Analysis of Scientific Books, 411 



r 

 " Hence hydraulic mortars, made with common lime, require 



more time than the others to attain their maximum of resistance." 



—p. 58. 



" On the Nature of Hydraulic Lime, — The modification which 

 the action of the fire has caused in the small proportion of silex 

 and alumine, mixed with the pure calcareous matter, gives to 

 the compound which results, the power of acting chemically by 

 the intervention of water on the new siliceous substances, 

 added in the state of sand. It is this circumstance which 

 constitutes the .distinctive and essential character of hydraulic 

 lime."— p. 73. 



" On the Use of the Siliceous Sand. — According to our 

 results, the different sands range in the following order of 

 superiority. 



" For highly hydraulic lime : 1. Fine sand. 2. Sand of un- 

 equal size resulting from the mixture of fine sand, either with 

 coarse sand or with small gravel. 3. Coarse sand. 



" For lime moderately hydraulic : 1. Mixed sand. 2. Fine 

 sand. 3. Coarse sand. 



*' For common lime : 1. Coarse iand. 2. Mixed sand. 3. Fine 

 sand. — ^p. 74. 



*^ Rapidity of Desiccation. — Mortars made from hydraulic lime, 

 which have the power of solidifying all the water they contain, 

 require to be dried slowly. They lose, according to circum- 

 stances ; namely, by common desiccation, three-tenths, and by 

 rapid desiccation eighth-tenths of the force which they would 

 acquire by slow desiccation." — p. 77. 



2 E !J 



