The gas to be checked is admitted through tube 6. As the space above bell-shaped member 1 is filled with the gas, the pressure inside and outside the member differs. As a result, member 1 and weight 3 are displaced vertically. At this, hand 5, turning about fixed axis A, indicates the density of the gas being checked. Weight 3 is connected by a flexible link to lever 2. Weight 4 keeps the flexible link taut.
$3933$LHP,M$