CLAY WORKING INDUSTRIES. 



139 



As has been before indicated it is probable that there are few clay 

 deposits in the state which are able to satisfy all of the conditions of 

 fire qualities and physical qualities also. But the Coal Measures abound 

 in the materials which are capable of giving the proper qualities by 

 judicious mixture. 



The following table of analyses was furnished by the Haydenville 

 Mining and Manufacturing Co., who manufacture the Hayden paving 

 and sidewalk blocks in one plant, and fire proofing and sewer pipe in 

 another, side by side. The value and benefits of maxing are well exem- 

 plified in this case for out of the clays of this table, they are able to pro- 

 duce material of the best quality and reputation in each of the lines they 

 have developed. 



TABLE VII. 



Silica, total 

 Alumina.... 

 Iron Oxide. 



Lime 



Magnesia... 



Alkalies 



Water 



Totals . 



69.92 



23.46 



.20 



.48 



.40 



1.43 



3.84 



99.73 



76.24 



16.87 



.16 



.50 

 1.09 

 4.90 



99.86 



62.05 



27.71 



.60 



.15 



.20 



2.40 



6.67 



99.78 



61.86 



26.02 



.63 



.19 



1.26 



.31 



9.98 



100.25 



62.10 



22.71 



3.69 



.71 



.86 



3.65 



6.03 



9.75 



E. M. Reed, Chemist. 

 No. 1. Soft Lower Mercer. 

 No. 2. Hard Lower Mercer. 

 No. 3. Soft Brookville Clay. 

 No. 4. Out-crop Lower Kittanning. 

 No. 5. Middle Kittanning. 



These clays are all fire clays, and it has been the policy of these firms 

 to confine their production to fire clay goods. However, it is highly 

 probable that even more beneficial results are attained by the mixture of 

 fire clays and shales. The vitrifying action in the shales is usually earlier 

 to begin and relatively slower in its progress than in fire clays, but many 

 shales are so near the danger line of fusibility that the margin of profit 

 is much diminished by the results of the least negligence or mismanage- 

 ment. If to such a shale, a good hard fire clay be added in proportion 

 of one-fourth or one-third and the machinery be such as will effect an 

 intimate mixture of the two, the result is all that would be desired, being 

 refractory enough and yet easy to vitrify, having still a good dark color 



and some glaze. 



Instances of the use of the good qualities of shales and fire clays 

 conjointly to do what neither would profitably do alone are very common 

 in the state. Some of the best vitrified goods in the market are produced 

 from such material. 



