SPECIFICATIONS FOR BITUMINOUS EOAD MATERIALS. 57 



(6) Thermometer: The thermometer shall conform to the following require- 

 ments : 



It shall be made of thermometric glass of a quality equivalent to suitable 

 grades of Jena or Corning make. It shall be thoroughly annealed. It shall be 

 filled above the mercury with inert gas which will not act chemically on or 

 contaminate the mercury. The pressure of the gas shall be sufficient to pre- 

 vent separation of the mercury column at all temperatures of the scale. There 

 shall be a reservoir 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 graduation beginning at zero shall be numbered. The graduation marks 

 and numbers 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, 5mm. ; and shall not exceed diameter of stem. 



Length of bulb, 12.5 mm. ; permissible variation, 2.5 mm. 



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



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



The accuracy of the thermometer when delivered to the purchaser shall be 

 such that when tested at full immersion the maximum error from to 200° C. 

 shall not exceed the following : 



From to 200° C 0°.5C. 



From 200 to 300° C 1°.0C. 



From 300 to 375° C 1°.5C. 



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

 temperature of 74° C. below the boiling point of water at the barometric pres- 

 sure, at the time of test, and plunged into free flow of stream, the meniscus 

 shall pass the point 10° C. below the boiling point of water in not more than 

 six .seconds. 



The thermometer shall be set up as for the distillation test, using water, 

 naphthalene and benzophenone as distilling liquids. The correctness of the 

 thermometer shall be checked at and 100° C. after each third distillation until 

 seasoned. 



(c) Condenser : The condenser tube shall have the following dimensions : 



Adapter mm 70 



Length of straight tube " 185 



Width of tube " 12-15 



Width of adapter end of tube ^ " 20-25 



(d) Stands: Two iron stands shall be provided, one with a universal clamp 

 for holding the condenser, and one with a light grip arm with a cork-lined clamp 

 for holding flask. 



(e) Burner and shield: A Bunsen burner shall be provided, with a tin 

 shield 20 cm. long by 9 cm. in diameter. The shield shall have a small hole for 

 observing the flame. 



(/) Cylinders: The cylinders used in collecting the distillate shall have a ca- 

 pacity of 25 cc, and shall be graduated in 0.1 cc. 



4. Setting up the apparatus. — The apparatus shall be set up as shown in 

 figure 8, the thermometer being placed so that the top of the bulb is opposite 

 the middle of the tubulature. All connections should be tight. 



