36 



BULLETIN 1036, U. S. DEPAETMEISTT OF AGEICULTURE, 



duplicate commercial conditions on a laboratory scale. It was found 

 that air under a pressure of 7 inches completely fulfilled this condition 

 with the still that was used, and that by using this air pressure the 

 creosotes made at the laboratory agreed as closely as could be 

 expected with commercial oils from the same tar. Figure 15 shows 

 the indices of refraction, the specific gravities, and the sulphonation 

 residues of two creosotes, one made at the laboratory and the other 

 at a commercial plant from tar No. 1. Figure 16 shows the index of 

 refraction values and the specific gravities of another pair of creosotes 



FRACTION 

 }Oc 





































^ 



















/ 









fe5l.60 



X 













y 



/ 

















-> 



/- 











o 







1 

































/ 







>- 



1- t Ofi 

















/ 







5u 















,jf 































%^ 











/ 



/ 











8> 1.02 









.j^ 



/ 



































220 240 260. 280 300. . 320 

 TEMPERATURE (NOT CORRECTED) *C 



Fig. 15. — Physical cousUnts of two coal-tar creosotes 

 produced from tar No. 1. 



Comniercial coal-tar creosote — Dotted line. 

 Experimental coal-tar creosote — Soad line. 























u 



% 1.63 



1- 



































/^ 





21.62 



1- 

















/' 

















/ 







a. 



w t.6t 













J 



/ 

















A 









o 



Sl.60 



o 

 z 











/ 



' 













^ 



^' 













1 <;o 















• 







1.08 



1.06 



5 I, 



C9 



tl, 



04 



02 



1.00 















/ 

















/ 



/ 















/ 



/ 

































// 

















/ 



^ 















^ 



































240 260 280 300. „ 320 

 TEMPERATURE ^ORRECTED) "C 



Fig. 16.— Phisical constants of two coal-tar creo- 

 sotes produced from tar No. 2. 



Commercial coal-tar creosote— Dotted line. 

 Experimental coal-tar creosote — So' id line. 



produced from tar No. 2, and figure 17 shows the indices or refraction 

 of two other pairs of creosotes made from tars No. 3 and 4, respec- 

 tively. These figures show that creosotes can be produced from tars 

 in the laboratory in such a way as to duplicate commercial condi- 

 tions, and can be made as nearly identical as two anal3^ses of the 

 same oil. 



In view of the fact, however, that not aU tar (hstillers use air in 

 their operation, it was decided that all work on authentic tars should 



