1843.] on the effects of Sea-water on Iron. 1077 



The " Phlegethon" left England with a clean bottom, having when 

 on the slip received three coats of red lead and three of black varnish, 

 which with an additional coating we partly succeeded in putting on at 

 the Mozambique, will I hope be found to have entirely preserved the 

 iron from corrosion, as at Mozambique I observed the coatings of red 

 lead remained perfect, when the blacking had been worn off. 



The first barnacles appeared and rapidly increased after crossing 

 the Tropic, with another species, I think called the Teredo. 



These were invariably scraped off on the arrival of the vessel in 

 port, as well as a narrow belt of soft green weed, of which the water 

 line was the margin, and the depth 8 to 9 inches, and of most rapid 

 growth. 



These obstructions to the vessel's sailing have, in from three to five 

 weeks, become very great, reducing her rate of sailing frequently one- 

 ninth, and occasionally upwards. 



The barnacles are fast disappearing since our arrival in fresh water. 



I have, &c. 

 (Signed) R. F. Cleaveland. 

 W. B. O'Shaughnessy, M. D. 



(True Copy.) 

 (Signed) C. B. Greenlaw, Secretary. 

 Fort William, Marine Superintendent's 

 Office, the 23d Sept. 1843. 



(Copy.) 



To T. H. Maddock, Esq. 



Dear Sir, — I beg to have the honor of laying before you, a few 

 remarks upon the nature of iron considered simply with relation to its 

 adaptation for the entire construction of the hulls of Sea-going Vessels. 

 The grand experiment of the practicability of this has been sufficiently 

 and satisfactorily tried, by the recent arrival from England of three 

 large Steamers built wholly of iron, but questions of great moment 

 respecting the integrity (for want of a better term) of this metal when 

 exposed to the chemical action of air or water, and also concerning the 

 evils that are occasioned by the facility with which several kinds of 

 marine animals appear to attach themselves to its surface, still occupy 

 the attention of many very able naturalists, with the view ofdetermin- 



