220 J. C. MOULDEN. 
Microphotograph of Cordierite in the Granulite, X 32. 
Objective 13”. Eyepiece ©. Light, ordinary transmitted. 
Actual diameter of visual field =-090’”. Dimensions (actual) of 
large grain of cordierite = -079” x ‘030’. Exposure, three minutes. 
Light, paraffin lamp. Plate, Paget. Developer, hydroquinone 
soda. 
