1908-04-04: A NEW APPARATUS FOR SUBMARINE OPERATIONS. A Submerged Operating Chamber Fitted with Helmets and Flexible Arm Sleeves is in free Communication with the Surface Through a Collapsible Vertical Shaft
1908-04-04: A NEW APPARATUS FOR SUBMARINE OPERATIONS. A Submerged Operating Chamber Fitted with Helmets and Flexible Arm Sleeves is in free Communication with the Surface Through a Collapsible Vertical Shaft
