HOLLOW WARE FOR STRUCTURAL WORK. 283 



Fireproofing Company, which has its headquarters at Pittsburgh, 

 and whose original plant in New Jersey was the factory at Port 

 Murray, Warren county, which uses Hudson shale (PL XXXIII, 

 Fig. 2). In 1900 this company acquired the Perth Amboy 

 Works, known as the Old Pardee Works; in January, 1901, the 

 fireproofing factory at Lorillard was taken over, and in July, 

 1 90 1, the Raritan Hollow & Porous-Brick Company at Keasbey. 

 Other factories are those of C. W. Boynton, Sewaren, and one 

 located at Spa Springs, which began in 1869 as the Anness 

 Pottery, and was subsequently known- as Anness & Lyle, Staten 

 Island Terra-Cotta Lumber Company, and is now the Staten 

 Island Clay Company. 



In addition to the nine factories above mentioned, fireproofing 

 is now manufactured by the Brinkman Terra-Cotta Company, 

 near Piscataway, and by the National Clay Manufacturing Com- 

 pany, of South River, which purchased the old Edgar Brick 

 Works in 1902, and has more or less re-modeled them. Anness 

 & Potter, at Woodbridge, also began the manufacture of fire- 

 proofing during 1902, and some hollow brick are made at Cross- 

 wicks by John Braislin & Son (PI. XXXIV, Fig. 2). 



The rapid growth of this industry in New Jersey is clue to 

 several causes. It is for the most part due to an inexhaustible 

 supply of clay, which in former years had little or no* value, and 

 even at the present day would probably not be put toi any use other 

 than that for which it is now dug. Furthermore, these clay de- 

 posits are in general close to tide water, so> that the product can 

 be shipped either by boat or rail to the large eastern markets. 

 Cheap fuel is also- an important factor. 



CONDUITS. 



Clays and manufacture. — Conduits form a line of clay prod- 

 ucts, the use of which has greatly increased in the last few years. 

 These are hollow blocks of varying length, having sometimes 

 several cross partitions and rounded edges, and are used for 

 pipes for electrical cables and wires below ground. On this ac- 

 count they have to be hard-burned, with dense body, and are 

 salt-glazed. 



