Take a cubic millimetre of hydrogen.
"The Story of Evolution" by Joseph McCabe
Now, the volume of the curie is only a little more than one half a cubic millimetre.
"The Birth-Time of the World and Other Scientific Essays" by J. (John) Joly
No property of the blood has been so exactly and frequently tested as the NUMBER OF RED CORPUSCLES PER CUBIC MILLIMETRE OF BLOOD.
"Histology of the Blood" by Paul Ehrlich
Their greatest volume therefore can only be an eighth of a cubic millimetre.
"Are the Planets Inhabited?" by E. Walter Maunder