METHODS FOR HANDLING SMALL AMOUNTS OF MATERIAL 297 



crucibles require a special support during ignitions casseroles 

 will be found more convenient. 



Grinding, Crushing, Mixing. — For grinding and crushing 

 materials for analysis, the smallest available agate mortars are 

 best. One not larger than 30 millimeters in diameter, Fig. 159, 



Fig. 159. Agate Mortar for Microchemical Analysis. (Full Size.) 



should be selected. It must be carefully scrutinized with a lens 

 to see that its inner surface is properly polished and is free from 

 fissures, pits and scratches. A mortar made from a first quality 

 piece of agate, if properly cared for, should last a lifetime. 



