PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 483 



failure, but she is in existence to-day, a staunch ship. This 

 Great Britain was the steamer which went ashore on the Irish 

 coast, and lay nearly two years exposed to storm, yet she is now 

 running to Australia and other ports. Now we have the Great 

 Eastern, the greatest triumph of genius that this age can boast 

 of, a ship which stamps her projector with immortality. It is 

 impossible to sink her, because she is stronger than the sea, and 

 made of good wrought iron, hermetically sealed. Some say she 

 will rust out, but that cannot come to pass, as her bottom will 

 become covered with barnacles, which will preserve her. Cast 

 her on a lee shore, and although half her compartments may be 

 broken into, a thing not likely to happen, yet she will still sur- 

 vive. If the whole of the British navy had been exposed to the 

 winter of the year during which the Great Eastern was exposed, 

 they would be all destroyed. He stated that he was in Liver- 

 pool in 1846, when the Great Britain came in after being ashore, 

 and had her bottom bilged in, which, however, did not do her 

 any material injury, as she is still in existence. Put her in the 

 cliffs of Dover, exposed to the roughest storms, and she would 

 still weather it out. That Dr. Crosby had measured the sea, and 

 found that the greatest blow it can strike is 30,000 lbs. to the 

 superficial foot of 144 inches; that it is impossible for her to be 

 lost, and unless a man falls overboard or down the hatchway, he 

 would be as safe on board of her as he would be on shore, and 

 that it was the interest of railway companies to patronize her. 

 He concluded his remarks by saying that she had not made an ex- 

 traordinary fast run from Southampton to New York on this her 

 first trip, but expected that when she had a clean bottom, and' 

 was cleansed of the barnacles which adhered to her keel, she 

 would make the passage in eight days. 



Mr. Fisher produced a tube of No. 25 wire gauge, one-fifteenth 

 of an inch in thickness, which he stated could be made water- 

 tight, and wished to know what is the maximum thickness that 

 a tube can be made of, so as enable it to bear a maximum pres- 

 sure of 200 pounds. 



CUT-OFFS IN STEAM ENGINES. 



Mr. Rowell stated that Mr. Hedrick wished to have the 

 matter of the "cut-off" delayed, as he had not called the com- 

 mittee together. He then read a paper which contained the 

 result of some experiments made on the subject of using steam. 



