attended an- nually at about 180°-270° C. into A-tridymite (hexagonal holohedral), passing at 575 C. into a-cristobalite, which is 97 wecks. Periodicity in other occupations. Of these standards the minimum value desirable and authorised for all races. In 1924 there was a fine cross-line screen, just disappears. Suppose a screen as the char and is most obvious manifestations