PART IV. METHODS OF TESTING CREOSOTES AND OFFICIAL 

 SPECIFICATIONS FOR CREOSOTE. 



CHAPTER I. PRACTICAL METHODS OF TESTING CREOSOTES. 



A number of tests have been proposed for creosote which, in gen- 

 eral, are of considerable service when materials of known source are 

 to be examined. The 



tests fail, however, if an : H \< 6 rnm. 



attempt is made to deter- 

 mine whether the creo- 

 sote under test meets the 

 requirements for purity. 

 The following tests have 

 heen proposed and used. 



SPECIFIC-GRAVITY TEST. 



5 



if* 



•00 |r 



101 



102 



103 



104 



105 



106 



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<:32mm.> 





_>^ 



e 

 ^ 



^ 



s 



22 mm. 



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_ _smi^shot 



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Practically all specifi- 

 <cations for creosote re- 

 quire that it shall have a 

 •certain range of specific 

 gravity; sometimes it is 

 stated that the specific 

 gravity shall not be less 

 than 1.03 or more than 

 1.08, and sometimes that 

 it shall not be less than 

 1.03. The specific-gravi- 

 ty determination is effec- 

 tive only when straight 

 distilled oils are used. Water-gas- tar oils have practically the same 

 range. An oil of low specific gravity may be made to pass the 

 specifications for coal-tar creosote by the addition of tar. This would 

 also raise the distillation limits. The specific-gravity test, although 

 it is an exceedingly useful one when used with creosotes of kno^^ni 

 origin, does not identify the oil or exclude tar. Any approved method 

 of determining specific gravity will answer. An ordinary hydro- 

 meter is generally used. The dimensions of the hydrometer and 

 cylinder, and the details of the test adopted as standard by the 

 Ajnerican Society for Testing Materials, the American Railway Engi- 



87 



Fig. 40. — Hydrometer and cylinder used for specific-gravitj' test. 



