COAL-TAR AND WATER-GAS TAR CREOSOTES. 



95 



above the final graduation large enough so that the pressure will not become excessive 

 at the highest temperature. The thermometer shall be finished at the top with a 

 small glass ring or button suitable for attaching a tag. Each thermometer shall have 

 for identification the maker's name, a serial number, and the letters "A. S. T. M. 

 distillation." 



The thermometer shall be graduated from to 400° C. at intervals of 1° C. Every 

 fifth graduation shall be longer than the intermediate ones, and every tenth gradua- 

 tion beginning at zero shall be numbered. The graduation marks and number 

 shall be clear-cut and distinct. 



The thermometer shall conform to the following dimensions: 



Total length, maximum 385 mm. 



Diameter of stem 7 mm. ; permissible variation 0.5 mm. 



Diameter of bulb, minimum 5 mm. ; and shall not exceed diameter of stem. 



Length of bidb 12. 5 mm. ; permissible variation 2.5 mm. 



Distance, 0° to bottom of bulb... 30 mm. ; permissible vanation 5 mm. 



Distance, 0° to 400° 295 mm. ; permissible variation 10 mm. 



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o 







n 





AatQSfOS Popar Cofar 



for 



RnrxirT 



Th ^rmornQrar 



Cork Stopper 





BunsQn Burnar 



Fig. 45. — Arrangement of distilling apparatus recommended by American "Wood Preservers' Association 

 American Railway Engineering Association, and American Society for Testing Materials. 



The acciu-acy of the thermometer when delivered to the purchaser shall be such 

 that when tested at full immersion the maximum error shall not exceed the following: 



°C. 



From 0° to 200° C 0.5 



From 200° to 300° C 1.0 



From 300° to 375° C 1. 5 



The sensitiveness of the thermometer shall be such that when cooled to a tempera- 

 ture of 74° C. below the boiling point of water, at the barometric pressure at the time 

 of test and plunged into free flow of steam, the meniscus shall pass the point 10° C. 

 below the boiling point of water in not more than six seconds. 



The retort shall be supported on a tripod or rings over two sheets of 20-mesh gauze, 

 6 inches square. It shall be connected to the condenser tube by a tight cork joint. 

 The thermometer shall be inserted through a cork in the tubulature with the bottom 



