1074 Experiments and Papers, [No. 144. 



I have the honor to inform you of one particular instance which 

 came under my notice about three years ago. When at anchor in the 

 " Swinton" a little below your wharf, a large Burman boat hooked a 

 chain, the original size of which must have been upwards of an inch in 

 diameter, and was lost with the Brig " Macaulay" about ten years 

 previous ; it was completely eaten away with rust, and broke with its 

 own weight in two fathoms of water; it must be taken into consideration 

 that this chain was lying m fresh water more than half the time above- 

 mentioned. 



As the tenor of your letter leads me to suppose that an object would 

 be gained by preventing corrosion on the bottom of iron steamers only, 

 I beg to forward three experiments of mine on sheet iron, the ingre- 

 dients are the same in each, but differ in quantity. 



No. 1 has two measures of dammer and one of chunam, with one- 

 sixteenth measure or less of artol, (or crude arsenic,) each pounded 

 separately and sifted through a fine sieve, to which is added a sufficient 

 quantity of wood-oil, and then well pounded together until it becomes 

 in substance a stiff paste. 



Directions for using the above. 



Heat the bottom of the vessel as on common occasions, and lay it on 

 with the hand, warm towels should immediately follow, which will make 

 it as smooth as may be required, and the vessel may be floated as soon 

 as finished ; each coat I feel certain will remain good under water 

 longer than any other composition yet known. 



The qualities of inferior composition have often been proved under 

 water on wood, with the exception of artol, but barnacles will adhere 

 to it, which the artol will prevent. 



On receiving your letter, I was doubtful whether the composition 

 would adhere to iron, which doubt I trust has now been removed by 

 the experiments now forwarded. 



No. 2 has one measure of dammer and one of chunam, with the same 

 proportion of artol. No. 3 has three measures of chunam, and one 

 measure of dammer mixed and prepared as the above. 

 Moulmein, ist De- I have, &c. 



cember, 1840. (Signed) Thos. Kinsman, 



Commander H. C. Schr. " Swinton" 



