Transactions of the Royal Society. 347 



of the copper, was applied in four masses, two near the stern, two 

 on the bows. She made a voyage to Nova Scotia, and returned 

 in January, 1825. " A false and entirely unfounded statement 

 respecting this vessel," says Sir H., ** was published in most of 

 the newspapers, that the bottom was covered with weeds and 

 barnacles. I was present at Portsmouth soon after she was 

 brought into dock : there was not the smallest weed or shell-fish 

 upon the whole of the bottom from a few feet round the stern- 

 protectors to the lead on her bow. Round the stern-protectors 

 there was a slight adhesion of rust of iron, and upon this there 

 were some zoophytes of the capillary kind, of an inch and a half 

 or two inches in length, and a number of minute barnacles. For 

 a considerable space round the protectors, both on the stern and 

 bow, the copper was bright ; but the copper became green to- 

 wards the central parts of the ship ; yet even here the rust or 

 verdigris was a light powder, and only small in quantity, and 

 did not adhere, or come off in scales, and there had been evidently 

 little copper lost in the voyage. 



u I had seen this ship come into dock in the spring of 1824, 

 before she was protected, covered with thick green carbonate and 

 submuriate of copper, and with a number of long weeds, princi- 

 pally fuci, and a quantity of zoophytes, adhering to different parts 

 of the bottom ; so that this first experiment was highly satisfac- 

 tory, though made under very unfavourable circumstances." 



At Liverpool several ships have been protected, and have re- 

 turned after voyages to the West Indies, and even to the East 

 Indies. The proportion of protecting metal in all of them has 

 been beyond what Sir H. recommended, g 1 ^ to -fa; yet two of them 

 have been found perfectly clean, and with the copper untouched 

 after voyages to Demerara ; and another nearly in the same state, 

 after two voyages to the same place. Two others have had their 

 bottoms more or less covered with barnacles ; but the preservation 

 of the copper has been in all cases judged complete. 



In cases when ships are to be newly sheathed, some of the 

 experiments detailed in this paper render it likely, that the most 

 advantageous way of applying protection will be under, and not 

 over the copper : the electrical circuit being made in the sea- 

 water passing through the places of junction in the sheets ; and 

 in this way every sheet of copper may be provided with nails of 

 iron or zinc, for protecting them to any extent required. By 

 driving the nail into the wood through paper wetted with brine 

 above the tarred paper, or felt, or any other substance that may 

 be employed, the incipient action will be diminished ; and there is 

 this great advantage, that a considerable part of the metal will, if 

 the protectors are placed in the centre of the sheet, be deposited 

 and re-dissolved: so there is reason to believe that small masses 

 of metal will act for a great length of time. Zinc, in consequence 



