604 CLAY. ROAD MATERIALS, ETC. 



"The dried briquettes were placed in a down draft test kiln and 

 fired to 1225 C., trials being drawn at 25 intervals, the first at 950 C. 

 The per cents, porosity of the fired briquettes was determined in the 

 usual manner and are given in the following table: 



Temp C. Porosity. Color Hardness 



950 28.4 Light red 



975 12.3 do 



1000 8.6 Dark red Vitrified 



1025 7.5 Dark do 



1050 6.3 do do 



1075 6.1 do do 



1100 6.4 do do 



1125 6.4 do do 



1150 5.8 do do 



1175 7.1 do Overburned 



1200 7.4 Chocolate do 



"The material has a very satisfactory vitrification range and may 

 be easily burned in a commercial kiln. A good red color is developed 

 by burning. The use of this shale as a paving material could be es- 

 tablished only by abrasion tests on full sized blocks. The material 

 would be satisfactory insofar as working and vitrification behavior 

 are concerned. 



"Sample No. 101 (Blue Shale). The sample was prepared, molded, 

 dried and burned in the same manner as sample No. 102. The shale 

 has a drying shrinkage of 3.9 per cent., the water of plasticity being 

 17.5 per cent. This sample is not as plastic as sample No. 102, al- 

 though it may be worked by the stiff mud process. The per cents, poro- 

 sity as determined are given in the following table: 



Temp' C. Porosity. Color Hardness 



950 26.3 Buff and red Soft 



975 24.2 do do 



1000 22.5 do do 



1025 19.7 do Hard 



1050 19.6 do do 



1075 17.3 do do 



1100 15.9 Dark Steel hard 



1125 14.1 do do 



1150 11.2 do do 



1175 10.4 do do 



1200 15.4 do do 



1225 20.8 do do 



"The vitrification behavior of this shale is not so satisfactory as 

 that of sample No. 102, everburning taking place suddenly at 1200 C. 

 The minimum porosity, 10.4 per cent., attained at 1175 C., is perhaps 

 too high for a material designed to be used in the manufacture of 

 paving brick. The burning color of this shale is very inferior to that 

 of sample No. 102. 



"Very truly yours, 

 (Signed) "P. H. BATES, For the Director." 



Whiting and West Brick Plant. The Whiting and West 

 Brick Plant, located at the mouth of Nutter Run on the south 



