Abstract: A gas-absorption cell for use with spectrophotometric equipment having a generally circular housing or body formed with inlet and outlet openings for the passage therethrough of predetermined types of energy, there being an optical lens in the inlet opening for directing incoming energy to a highly reflective annular surface within the body whereby energy is permitted to reflect back and forth across the interior of the body, thereby making a plurality of different paths through a gas sample before it is caused to leave the cell through the output opening therein. Such cell configuration can be substantially coplanar or it can be in the form of a sphere; in either case, the plurality of paths through the gas includes substantially all of the interior of the cell. Also, two or more substantially coplanar cells can be arranged in juxtaposition with the energy being transferred from one cell to another by suitably positioned reflectors.