If possible, a pressure-gauge should be provided to indicate immediately if the air-pressure is excessive or the water is not being freely displaced.
Ukuba kuyenzeka, umlinganiselo woxinzelelo mawube khona ukubonakalisa ngokukhawuleza ukuba umoya onoxinzelelo ungaphezu komlinganiselo okanye amanzi angashenxiswanga ngokukhululekileyo.