709 



s- YORK si MUSEUM 



much sulfur in the fuel used. The effect of this sulfate of 

 lime, if it does not • \& to greatly delay the setting 



of the oement and also inorease its final strength somewhat. If 

 present to the extent of or 5^, however, both these qualities 

 disappear, Bince the formation of calcic sulfid is brought about, 

 which in turn n ith the iron compounds in the cement and 



bo disintegrate it. The effect of sulfate of lime is shown 

 in the aocompanying table, taken from Prof. Johnson's work, 

 M lie rials of construction (p. 1>7). 



The German tion of Portland cement manufacturers lias 



dared against any addition except up to the 2# CaS0 4 to regu- 

 late setting time. It is the general practice in the United States 

 now to put in 2# CaS0 4 to produce slow set. 



The following experiments are quoted by Lewis, showing the 

 effect of sulfate of lime on the rate of setting. 1 





ONK SORT OF CEMENT 



SETTING 

 TIME 



NEAT-CEMENT BRI- 

 QUET 



BRIQ. 1 CEMENT, 3 

 SAND 



HO. 



en 

 >» 



c3 



•a 



323 

 315 

 375 

 423 



818 



CO 



>» 



<& 

 •o 



405 

 454 

 508 

 543 



450 



co 



8 



518 

 572 

 568 

 688 



550 



CO 



J* 



© 



Ss 

 ex 



620 

 623 

 695 

 718 



592 



u 



as 



<W 



>> 



»-i 



700 

 650 

 780 

 805 



618 



■ 

 >> 



•o 

 t- 



115 

 142 

 1*9 

 180 



168 



- 



c8 



•c 



CO 

 CI 



168 

 212 

 238 

 263 



218 



CD 

 CO 



• 



w 



CM 



238 



CO 



M 



■ 



0) 



ft 



0* 



30? 



u 



4 

 © 



*-> 



1 





0° 20' 



8° 30' 



10» V 



14* V 



10° 80' 



360 



« 





:w.t RSI 



890 



n 



A% u 



311 

 305 



38 



368 

 375 



360 



384 



4 



.9* " 



410 



6 



No pyp. but kept in store for some 



431 









Results reported by John Grant in 1880. ! 



MIXTURE 



7 days 81 days 60 days 90 days 



1-1 briq. average of 5 107 159 188 267 



1-1 briq. w. II 2 S() 4 added to water; 



average of 5 129 227 200 255 



Results reported by Prof. Tetmajer in 1894. 3 



1 Min. ind. 6: 101. 

 • "6: 89, 90. 

 » Mitth. d. Aui rur Priifung v. baumaterialien. 1894. 7 hfte, p. 89. 



