REPORT OP THE DIRECTOR AND STATE GEOLOGIST 1901 1'93 



of the sand. Clay, though refractory enough as a constituent 

 of a molding sand, bakes at a high temperature, and therefore 

 tends to cause both shrinkage and loss of porosity. 



No analyses of American molding sands are available for 

 insertion in this paper. The analyses following will suffice to 

 give the reader a good idea of the composition of standard for- 

 eign molding sands. Of the 12 analyses given, numbers 1, 2, 3, 

 5 and 12 are to be found in Percy's Metallurgy, 1:152-54; while 

 the remaining seven analyses are quoted in Crook & Rohrig's 

 Practical Treatise on Metallurgy, 2:627. The analyses have, in 

 the following table, been arranged in the order of their content 



of silica. 



Analyses of molding sands 





Si0 2 



A1 2 3 



Fe 2 3 



CaO 



MgO 



K 2 



Na 2 



1 



92.913 



92.083 



91.907 



91.61 



90.625 



90.25 



88 



87.6 



86.68 



83-77 



79.02 



67.6 



5.85 



5.415 



5.683 



2.11 



6.667 



4.1 



2.78 



7.7 



9.23 



8.2-7.7 

 13,72 

 17.64 



1.249 

 2.498 

 2.177 

 2.53 

 2.708 

 5.51 

 3.77 

 3.6 

 3.42 

 4-2.8 

 2.4 

 al.6 



tr. 



tr. 

 .415 



tr. 



tr. 

 .23 

 .73 

 .96 

 .96 



.86 



.73-.38 

 .71 

 1.41 



5.78 \ 

 4. 

 3.69 





?, 





3 





4 

 5 

 6 







7 





8 





9 





10 

 11 

 12 



;o 3.17 

 58 



.14 



a FeO 2.3 



1 From Manchester, England. Analyzed by Kumpmann 



2 From the foundry of Freund at Charlottenburg 



3 Employed for bronzes at Paris, France 



4 Employed at Rothehutte. Analyzed by Streng 



5 From the establishment of Lagua near Stromberg 



6 From Lunenburg. Analyzed by Sauerwein 



7 From Konigshutte. Analyzed by Bierworth 



8 From Birmingham, England. Analyzed by Sauerwein 



9 From Sheffield, England. Analyzed by Sauerwein 



10 From Naples, Italy. Analyzed by Jwanow 



11 Employed at Ilsenberg. This sand is an artificial mixture, 

 and is said to " consist of three different kinds of material, 

 namely — common argillaceous sand, sand found in alluvial de- 



