C

Cartesian
10;

Chums of Chance
3; aeronaut club out of ...; 6, 7,

Chums of Chance and The Evil Halfwit
5;

Chums of Chance and The Curse of the Great Kahuna
5;

Chums of Chance in Old Mexico
7;

Chums of Chance at Krakatoa
6;

Chums of Chance Search for Atlantis
6;

Columbian Exposition of 1893
3; 10

Commandant of Earthly Days
17; a "potent though invisible" entity that dictates human behavior

Counterfly, Chick
4; member of the C of C

Counterfly, Richard "Dick"
7; father of Chick Counterfly; 17

Crack of Doom
12; The phrase at the crack of doom, meaning "at the striking of the fateful hour", is derived from Macbeth by William Shakespeare and has entered common usage. Wikipedia entry

cubeb
17; the name for the berry and for the oil obtained from the unripe berry of the East Indian climbing shrub P. cubeba. The dried fruits are sometimes used as a condiment or are ground and smoked in cigarette form as a catarrh remedy. The oil is used medicinally and also in soap manufacture. The masticated roots of kava, P. methysticum, widely grown in its native Pacific islands, are made into a beverage called kavakava, which contains soporific alkaloids. It is an integral part of religious and social life there. A preparation of kava for commerce, also called kavakava, is sold widely as an herbal remedy for anxiety and insomnia. -- From The Free Dictionary