■674 NEW YOEK STATE MUSEUM 



slaking Increases with tlie decrease of impurities. The same lime 

 may show a varying increase in volume in slaking due to amount 

 of water added, etc. The slow addition of water raises less hea,t, 

 and slaking lime in an open box gives less heat than in a closed 

 one. 



With an equal volume of water the increase in size of a rich 

 lime is 2 to 2.4^. Eichardson illustrates this point as follows: 



Yol. of HgO Increase in volume 

 i 1.6 



1 2 

 2i 2.5 



With a poor dolomitic lime it was 



2 1.7 



ISTo set rule can therefore be laid down. For instance, 1 peck 

 lump lime with 44^ of voids, on slaking with its own volume of 

 water, gave 2i pecks of fine powder of slaked lime. From 1 

 peck of closely packed lime, 2.5 vol. of slaked lime were obtained. 



Gilmore found large increases, some running 2.46, 2.83, 3.21, 

 -2.40, but this was caused by his using larger amounts of water 

 than are generally taken in practice. 



The following table gives the tests made by both Gilmore and 

 -Kichardson. 



Weight of lime in pounds 



Vol. of lime in cubic centimeters . . 



Vol. of water required 



Increase of weight to slake, in ^. . 

 Increase in volume 



The theoretic increase is 1.53. Lime also slakes simply on 

 exposure to the air, but this is not good for mortar-making, as 

 the slaking has not been accompanied by any violent disengage- 

 ment of heat to rupture the mass. The larger particles also have 

 B. hardened rim. 



Rockland Rondout 

 Gilmore 



New York 

 Richardson 



5 



5 



5 



1557 



1806 



2 350 



2 983 



3 300 



2 000 



2.24 



2.24 



1.6 



2.46 



2.14 



1.91 



