A medical respiratory apparatus includes a chamber (10) which is at least in part at least translucent. The chamber (10) includes a float member (12) formed of an inert material and contains, in use, a fluid intended for inhalation. The float member (12) is adapted to float upon the fluid intended to be contained within the chamber (10) and has a peripheral dimension adjacent, but less than, the internal peripheral dimension of the chamber (10). At least the outer peripheral surface of the float member (12) has a coloration distinct from that of the fluid to be contained within the chamber such that the level of the fluid within the chamber (10) can be readily observed.