If nuclear lengths, masses, times, energies, actions, etc., are compared with corresponding cosmological quantities, the resulting dimensionless ratios are near unity or near a small, half-integral power of1080, which is picturesquely called the “number of particles in the universe.” These “numerical coincidences” are collected and shown to imply probably a single relation between atomic and cosmic structural constants. They may be used to define two systems of units such that any quantity has a measure in the “elementary” system which is an integral power of1040times its measure in the “cosmical” system. Both systems are theoretically convenient, the “elementary” havingcandhunity, and the “cosmical” havingcandGunity.