air under a pressure of fifty atmospheres. This tank is fastened to the back by means of straps, like a soldier’s knapsack. Its top part forms a box where the air is regulated by a bellows mechanism and can be released only at its proper tension. In the Rouquayrol device that has been in general use, two india-rubber hoses leave this box and feed to a kind of tent that imprisons the operator’s nose and mouth; one hose is for the entrance of air to be inhaled,
air under a pressure of fifty atmospheres. This tank is fastened to the back by means of straps, like a soldier’s knapsack. Its top part forms a box where the air is regulated by a bellows mechanism and can be released only at its proper tension. In the Rouquayrol device that has been in general use, two india-rubber hoses leave this box and feed to a kind of tent that imprisons the operator’s nose and mouth; one hose is for the entrance of air to be inhaled,
