4 CONTENTS. 
Part I. Scientific discussion — Continued. Page. 
Granite proper — Continued. 
Maine granites — Coutinued. 
Rock variations - - 42 
Dikes (granitic) 42 
Veins (quartz) 46 
Dikes, basic 47 
Segregations ( knots ) - 49 
Geodes 49 
Inclusions - 49 
Contacts 51 
Minerals on joint faces 51 
Discoloration ( ' ' sap, ' ' etc. ) 52 
Decomposition 54 
Black granites 56 
Black granites in general 56 
Classification 56 
Origin . 57 
Mineralogical and chemical composition 57 
Texture - 58 
Physical properties 58 
"Black granites " of Maine 59 
Classification 59 
General structure 60 
Rift „ . . . 60 
Sheets 60 
Joints 60 
Variations in the rock 60 
Banding 60 
Dikes 61 
Contacts 61 
Text-book references on granite and " black granites " 62 
Part II. Economic features ■ 63 
Tests of granite 63 
Chemical analysis 63 
Determination of ( .'< », and CaO 63 
Discoloration 63 
Mineral composition 63 
Proportions of minerals 64 
Polish 64 
Hardness 64 
Compressive strength 65 
Transverse strength, shearing strength, and compressive 
elasticity 65 
Porosity 65 
Freezing and thawing 66 
Absorption and compression 66 
Behavior under fire . . . 66 
Specific gravity . . 66 
Weight per cubic foot 66 
Coefficient of expansu >n 66 
Adaptability to different uses 67 
Granite quarrying 67 
Exploration of surface . 68 
