Observations on the Temperature oftheOcean andyltmosphere.TJ 



entirely unfit for use — that the one shall (or perhaps tnay) be 

 infected with the drv-rot — the other free from such disease. 



" I have conversed with men of great experience and knowledge 

 in timber, and the result has always gone to strengthen my opi- 

 nion, that the oak timber has not degenerated ; but that the 

 drv-rot is given it bv the improper mode of cutting it down and 

 preparing it for use ; and I am firmly persuaded that, in a ship 

 built of timber so prepared, this destructive di.-ease will never 

 make its appearance. 



" I could expatiate on this subject, and adduce the opinions of 

 others to qualify what I have stated ; but I think it will re(|uire 

 little argument to show that a tree cut down in its natural state, 

 and seasoned in the mode I have described, will be a more solid 

 substance, finer-grained, and consequently less liable to be in- 

 fected with any disease, than that of a tree cut down, imme- 

 diately stripped of its bark, and left exposed to the elements, 

 from which, in fact, the disease is absolutely engendered. 



" In making these suggestions I have been actuated by the good 

 of mv countrv; and if they should ultimately prove to be founded 

 on a solid basis, and that benefit will result from them, I feel 

 great confidence that they will, by th.e Honourable Board, be 

 appretiated accordingly; and, 



" I am, Hon. Sirs, 



" Your obedient servant, 

 " To the Hon. the Commissioners John Shilubeer, 



of the Navy, &'c. London. 1st Lieut. Roy. Marines." 



" P.S. A small reduction in the tax on leather would prevent 

 an inconvenience to tlie public from any rise in bark, and the ex- 

 penditure of the navy would be considerai)ly reduced. — J. S." 



*^:* I have been just informed that orders are issued not to 

 receive timber into the Dock-yard that has been barked ; — if so, 

 and it be attended with success, these suggestions of Lieut. S's 

 will reflect great credit on him. 



VI. Observations on the Temperature oj' the Ocean and Atmo- 

 sphere, and on the Density of Sea-water, made during a 

 Vojjage to Ceylon. In a Letter to Sir Humphry Davy, 

 LLD. F.R.S. By John Davy, M.D. F.R.S.* 



Mv DEAR Brother, xTircoRDiNG to the promise contained in 

 a former letter, I proceed to give you a short account of the ob- 

 .servations which I made during my late voyage from England to 

 Ceylon. At present, I shall confine myself chiefly to three to- 

 • F»oin the Transactions of the Royal Society for 181 7, part ii. 



pics. 



