monteath's forester's guide. 161 



shipping. If the quantity necessary be not greater 

 than what we have supposed— even Mr Hume him- 

 self would not consider the expense extravagant — 

 the preservation of a line-of-battle ship not exceed- 

 ing that of one of our numerous army captains "while 

 lying in ordinary. 



Lime is preventive of dry-rot in sever-al ways, — » 

 when uncombined as an antiseptic, simply by dry- 

 ing, from its attraction for water ; by its causticity, 

 which remains for a number of months after it is 

 slaked, destroying organic life ; and by its absorb- 

 ing putrescent gases. It is not easy, without trial, 

 to form a correct estimate of the quantity of mois- 

 ture which would enter through the inside planking 

 of a man-of-war ; but were the bottom of the vessel in 

 good condition, the pumps attended to, and external 

 air excluded, we should consider that the moisture 

 would not greatly exceed 60 tons of water yearly,^ 

 which would nearly be required to convert 240 tons 

 of lime-shells into dry hydrate of lime. No very 

 great injury or inconvenience would be produced 

 I by the opening of the seams of the ceiling (the 

 inside skin), or of the inner decks or floors, or by 

 the warping of the plank, resulting from the con- 

 traction of the timber by the dryness; but the caulk- 

 ing of the main deck would require to be looked to, 



i 



