xxvi PREFACE. 



refractoriness. The series of tests carried out in this connection 

 include all the brands made in the State, with the exception of 

 those of three manufacturers, one of whom maintains only a 

 branch establishment in New Jersey, who declined to permit their 

 brick to be tested. It is, of course, impossible to say whether this 

 reluctance on their part arose from a disbelief in the express 

 promise of the State Geologist that the identity of the various 

 brands would not be made known, or from a consciousness that 

 their brick would not compare favorably with other brands, or 

 from some other reason. In strong contrast to 1 this attitude was 

 that of the other manufacturers, most of whom were not only 

 willing to have the tests made, but were willing to- have the 

 results published under their own names. 



So far as known, this set of fire-brick tests is the most complete 

 ever published in this country. A careful study of the fusion 

 temperatures in comparison with the chemical composition can- 

 not fail to' indicate many important points, one of the most 

 marked of which is the effect upon the fusion of a large amount 

 of free silica, and of the fineness or coarseness of its grain. 



It is with great pleasure that acknowledgment is made to all 

 who have supplied information or assisted in the preparation of 

 this report. By clay miners and clay manufacturers, by foremen 

 and superintendents, by laborers and proprietors, we have been 

 received with a courtesy and attention so uniform that the very 

 few instances where information has been refused and the door 

 shut in our faces stand out strongly by contrast. While thanks 

 are due to many, especial mention must be made of favors 

 received from Messrs. J. A. Campbell and E. C. Stover, of the 

 Trenton Potteries Company; Alfred Law she, of the Trent Tile 

 Works; J. E. Rossi, of Perth Amboy ; M. D. Valentine, of Wood- 

 bridge ; E. C. Fisher, of the Sayre & Fisher Company, and. Mr. 

 O. Speir, of the Perth Amboy Terra Cotta Company. Messrs. L. 

 C. Gratton, Fellow in Geology, and W. E. McCourt, Assistant in 

 Economic Geology, at Cornell University, gave very material 

 assistance in the chemical and physical analyses, and the latter 

 also made most of the drawings for the report. 



It is, perhaps, too much to hope that no errors have crept into 

 these pages. The compilation and sifting of all the data collected 



