70 MISC. PUBLICATION 679, U. S. DEPT. OF AGRICULTURE 



to a sufficient extent to eliminate the cracked areas, and then refinishing 

 them as before. It is better practice, however, to place such blocks in fair- 

 ly tight-fitting molds and subject them to the annealing heat-treatment 

 for a suitable length of time before proceeding with the resurfacing and 

 polishing. 



