SAMPLING AND TESTING HIGHWAY MATERIALS. 53 



be made by a fixed, arbitrary, and closely defined method if the results obtained are 

 to be comparable. 



I. APPARATUS. 



(2) The apparatus shall consist of the following 



din l br r "^ 15 f o mm - (f lnCh) ln in8ide diameter and 6 -35 mm. (J inch) 

 deep thickness of wall, 2.38 mm. ( A inch) permissible variation on inside diamete 

 and thickness of rmg, 0.25 mm. (0.01 inch). This ring shall be attached in a con 



venient manner to a No. 15 B. & S. gauge brass we (diameter 1.79 mm. =0.0703 

 mcnj. (bee fig. 29.) 



g rlms A 8teel baH 9 " 53 mm " ^ lnCh) ^ diamete1 ' WeigMng betWeen 3 - 45 and 3 - 55 



(c) A glass vessel, capable of being heated, not less than 8.5 cm. (3.34 inch) in 

 diameter by 10.5 cm. (4.13 inch) deep. (A 600 c. c. beaker, Griffin low form meets 

 this requirement.) ' " xwu> 



(d) A thermometer which shall conform to the following specifications: 



DSmete- Sth c 3 l° + t0 40 ° mm " ^ 14 " 57 t0 15 - 75 in ^s). 



BulMenoth 6 - 5 + t0 7 " 5 mm - < - 256 to °' 295 inch )- 



5, S ; not over 14 mm ' ( not over 0.55 inch). 



Bulb diameter 4.5 to 5.5 mm. (0.177 to 0.215 inch) 



