Calories (20°C)
A Calorie (20°C) is sometimes referred to as a small calorie or gram calorie. It is a unit of energy defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius from 19.5°C to 20.5°C.
Ergs
An erg is a unit of energy defined as the work done by a force of one dyne exerted over a distance of one centimeter which is equivelent to 10-7 joules.