Proceedings of the Polytechnic Association. 877 



making a large piece of steel ; such as is required for tlie shears of 

 nail macliines, could not be made and tempered without cracking. 

 The quality of iron used for gun metal is that which has from three 

 to four per cent of carbon. A piece of brass treated in the same 

 way for tempering steel, becomes softened. This he attributed to 

 the better conducting power of the braes than the steel. 



The following paper by H. B. "Wilson, Esq., was then read by the 

 author : 



Ocean I^avigation and Postal Subsidies — The Tkans-Atlantio 

 Carrying Trade — How We Lost it and How to Regain it. 

 Early in the present centur)^ our ship builders began to acquire 

 notoriety for their skill in naval architecture. Shortly after the close 

 of the war with England, 1812-14, which was forced on us by the 

 gross interference of that country with our maritime rights, this skill, 

 together with the enterprise of our merchants, led to still more 

 important results in the improvements introduced in the models and 

 accommodations of our ocean ships. The most marked features in 

 these improvements consisted in the gradual increase in size and 

 diminution in their draft. The enlarged dimensions took the direc- 

 tion of length rather than breadth of beam, and the floors of ships, 

 year by year, were made more llat, and were carried further fore and 

 aft. Thus, while an English Indiaraan of 800 tons register was only 

 120 feet long between perpendiculars, an American liner, of the same 

 tonnage, would be 160, and, while the former drew twenty-two feet 

 of water, laden, the latter floated in eighteen or nineteen. Our naval 

 designers also discovered the efiicacy of the hollow water, or wave 

 line, in displacing and replacing the water, wliile European builders 

 continued, for many years longer, to use the convex form of entrance 

 and run in their ships. 



From these causes our ships became so superior to those of English 

 build that we acquired almost a monopoly of the best paying passen- 

 ger and freight business. For twenty years prior to 1840, our lines of 

 packet ships between New York and Liverpool, London and Havre, 

 possessed the same sort of -reputation and prestige as that since 

 acquired by the English steam lines. Their size, superior accommo- 

 dations, and the pleasures of a voyage in these old liners, were the 

 frequent subjects of eulogium and description by the first writers of 

 both countries, and especially by our great novelist. Cooper. Those 

 who desire to learn how much praise was bestowed on these then noble 



