VOLCANIC TUFF. 



397 



Por piirposes of comparison I have recalculated the results ^ of sonie 

 Wisconsin building stones which are given below : 



Table V. — Transverse strength of Wisconsin Jiuilding stone. 

 SANDSTONE. 



Babcoek and Smith quarry 



Bass Island Brownstone Co. quarry __ 



C. and N. W. Ey. Co. quarry 



Flag River brownstone quarry 



Grover red sandstone quarry 



Grover red sandstone quarry" 



Prentice Brownstone Co. quarry 



Num- 

 ber of 

 sam- 

 ples 

 aver- 

 aged. 



Length. 



Breadth. 



Height. 



Weight 

 o{ load. 



Cm. 



Cm. 



Cm. 



Kilos. 



8. 89 



2.55 



2.85 



57.8 



8.89 



2.45 



2.65 



49.4 



10.16 



2.58 



2.62 



83.0 



17.78 



2.78 



2.80 



25.6 



7.62 



2.70 



2.43 



35.8 



7.62 



2.45 



2.45 



13.6 



12.70 



2.72 



2.81 



41.3 



Modulus 

 of rup- 

 ture per 

 square 

 centi- 

 meter. 



Kilos. 

 37.0 

 41.8 

 71.3 

 31.3 

 25.5 

 10.6 

 36.5 



LIMESTONE. 



Bridgeport quarry 



Story Bros, quarry 



Marblehead L. and S. Co. quarry 



Menominee Falls Co. quarry 



Laurie Stone quarry 



1 



15.24 



2.69 



2.71 



7L2 



2 



15.24 



2.41 



2.76 



120.2 



1 



15.24 



2.73 



2.73 



227.3 



1 



15.24 



2.77 



2.62 



185.5 



1 



12.70 



2.66 



2.59 



307.5 



81.9 

 149.7 

 255.4 

 222.9 

 327.6 



GRANITE. 



Montello Granite Co. quarry- 

 New Hill O'Fair quarry 



10.16 

 10.16 



2.53 

 2.67 



2.75 

 2.66 



335.2 

 232.2 



266.8 

 177.1 



» Sample was wet. 



The modulus of rupture of the tuff is not high, but it is not necessary 

 that it should be since it is not used as caps and sills in heavy buildings. 

 The necessity of having a high niodujus of rupture was obviated in the 

 large buildings, for example the Guadalupe church, by using stone of 

 considerable thickness and by arching the doors and windows. 



Durability. — The durability of a stone depends chiefly upon its ability 

 to withstand the mechanical, physical, and chemical conditions to which 

 it is e.xposed. The most important durability tests which aid in de- 

 termining this are the specific gravity and porosity. 



Specific gravity. — The method employed was to weigh the sample in 

 air and then to weigh it, completely saturated with water, in water at 



'Buckley, E. R.: Bull. Wis. Geol. d Nat. His. Stir. {Econ. Sr. 2) 

 75034 7 



(1898), 4, 396. 



