18 BULLETIiSr 1036, V. S. DEPARTMEIS^T OF AGRICULTURE. 



Table 4. — Comparative yield of water-gas tar from different oils. 







Mixture contains— 





Volume 



of tar 

 produced. 



Class of oil. 



Base. 





Paraffin. 



Per cent. 

 2 to 4 





. ..do 



6 to 10 



Crude oils 



do 



8 to 12 







10 to 15 





do 



12 to 18 









PRODUCTION OF TAR IN THE UNITED STATES. 



The figures given in Table 5 show the number of gallons of coal tar 

 produced in the United States since 1904: 



Table 5. — Production of coal tar in the United States. 



Year. 



Retort tar. 



By-product tar. 



1904 

 1908 

 1912 

 1915 

 1917 



41,726,970(5) 

 68,541,220(5) 

 40,489,855(5) 

 47,863,192(7) 

 53,318,413(7) 



27,771,115(.5) 



42.720,009(5) 



94, 306,. 583(6) 



138,414,601(7) 



221,999,264(7) 



No direct figures are available on the amount of tar produced by 

 each type of retort or coke oven throughout this period. Some 

 general idea ma}", however 

 coke ovens in existence at the end of 1917: (8.) 



be obtained from the following list of 



Koppers : 3, 374 



Semet-Solvay 1, 831 



United Otto 2, 032 



Wilputte 78 



Gas machinery 60 



Klonne " 27 



Rothberg. 

 Roberts. . . 

 Didier 



281 



36 



150 



Total 7,869 



Idle 571 



The amount of water-gas tar produced and sold in this country as 

 given by the United States Geological Survey is shown in Table 6 : 



Table 6. — Production of water-gas tar in the United States.^ 



Year. 



Produced and 

 sold. 



1905 

 1908 

 1912 

 1915 

 1917 



Gallons. 



9,2.30,411(9) 



9,168,834(5) 



34,000,000(6) 



51,381,911(7) 



59,533,208(7) 



1 F'llweiler (56) gives the production of water-gas tar in 1918 as approximately 70,000.000 gallons; in 1919, 

 75,000,000 gallons; and in 1920, 80,000,000 gallons. 



