Mk. Napiek on Copper Sheathing. 161 



5. S. oleoides (Decaisne) ; leaves linear or narrow oblong-lanceolate, 

 racemes short, flowers close sessile, stamens included. — Jacquem. Voy. iv. 

 t. 144. S. indica Royle. Wall. L. No. 7530. — Hab. Banks of the Jumna 

 and northern India. 



C. Lobes of the calyx erect, scarcely longer than the tubular calyx ; 

 stamens slightly protruded. 



6. S. madurensis (Decaisne). — Jacquem. Voy. iv. t. 144. — Hab. Island 

 of Madura, near Java. 



I am unwilling to enter upon the affinities of this genus ; the most pro- 

 bable conjectures are those lately made by M. Planchon, that Salvadora, 

 Doiera (to which he refers Schir.ocalyx coriaceus Hochst, and Blackhurnia 

 02}positifolia, or rather B. monaddpha, Roxb., and Azima, to which 

 il/owe<^a of L'Heritier SiXidi Adegeton of Blume are reducible), form a small 

 order allied to Oleaceae : at the same time the distinct petals and hypo- 

 gynous stamens of the two last of these genera, and the one-celled ovary 

 of the first, are considerably at variance ; while between each other they 

 have few common links, except the structure of the seed and number of 

 stamens. 



Messrs. Wm. Black and Jas. Murdoch, jun., were admitted members. 

 A new drainage level, patented by Mr. T. R. Gardner, Buchanan- 

 Street, was exhibited, and its construction explained by Mr. Bryce. 

 The following paper was read : — 



XX. — On Copper Sheathing, and the probable cause of Us deterioration. 

 By James Napier, Esq. F.C.S 



The objects for which ships and other sea-going vessels are covered 

 with metal are twofold. 1st. To prevent worms and other marine animals 

 boring into the wood and destroying the vessel ; and, 2d, To prevent the 

 adhesion of sea-weed and shell-fish to the bottom of the vessel, which 

 greatly impedes her progress and otherwise affects her sailing qualities. 



The protecting of sea-going vessels, by covering them over with metal, 

 appears to have been practised by the ancients. Leo Baptista Alberte 

 observed upon the remnants of a ship discovered in the neighbourhood of 

 Lake Reccia, that it had been sheathed with an alloy of copper. More 

 commonly vessels were covered over with wood; but when the milling of 

 lead was invented, about the year 1670, a patent was granted to the 

 inventor for sheathing vessels with milled lead, and this was practised for 

 a period of thirty years, but was afterwards given up and wood again 

 adopted. The reasons for abandoning the use of lead were tlic fouling 

 of the vessel, and the destruction of her iron work. Notwithstanding 

 these results, several patents have been since taken out for lead sheathing, 

 and the government, so late as 1832, made a trial of it on a hulk, but 

 the lead dropped olf by the rapid destruction of the nails which fastened 

 it. 



