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SUB-MARINE AND WRECK-WEIGHING MACHINES. 



A Company has been formed for this highly praise-worthy object ; the 

 following is a brief description of the method adopted in the process of 

 raising sunken vessels. " Supposing a vessel to have sunk with her 

 cargo, we go (say the company) to the spot as early as possible ; the 

 divers descend clothed in their diving dresses, inspect the wreck, secure 

 round her strong chains, such as are used for ships' anchors or moorings, 

 which are lowered from a proper vessel floating above, and from which 

 air is also supplied to the divers ; this done, they give signals to be 

 furnished with India-rubber air chambers (these chambers are constructed 

 of very strong fabrics, similar to the best sail cloth, with a very thick 

 layer of India-rubber between such fabrics, whereby they are air and 

 water-proof, and to which chambers sufficient length of pipe is attached); 

 these air chambers being fixed to the links of the chains previously made 

 fast round the wreck, are filled with air by the pumps, through the 

 connecting tubes before mentioned ; their size and number being such 

 that their buoyancy may be sufficient to again float the vessel, which can 

 then be conveyed to a place of safety." Now, it is a well ascertained fact, 

 that for every cubic foot of water thus displaced, a floating power of about 

 621bs, avoirdupoise is obtained ; the recovery of any weight from the bed 

 of the sea must appear easily practicable ; thus, supposing the air chambers 

 to be only 6 feet in diameter, and 18 feet long, they would contain 525 

 cubic feet of air ; which, if we reckon at GOlbs. per cubic feet, would give 

 a sustaining power of 14 tons each; twelve of these, six on each side, 

 would possess a raising power of 168 tons, sufficient to float a vessel of 

 upwards of 300 tons burthen. For larger ships, however, chambers of 

 12 feet in diameter, and 36 feet long (a size easily constructed), would 

 possess a power of upwards of 112 tons each, and twelve of this size 

 would have a power of 1,344 tons, which would raise a vessel of upwards 

 of 2,000 tons burthen; and a greater power maybe obtained, either by 

 increasing the number or size of the air chambers. Several vessels of 

 large burthen have been raised already by these means, by the Company's 

 Engineeer, Mr. Bush. 



