When the plastering is finished, a considerable time should be allowed for the work to get dry again before the skirtings, the floors, and other joiners’ work be fixed. Drying will be much accelerated by a free admission of air, particularly in favourable weather. When a building is thoroughly dried at first, openings for the admission of fresh air are not necessary _when the precautions against any new accessions of moisture have been effectual_. Indeed, such openings only afford harbour for vermin: unfortunately, however, buildings are so rarely dried when first built, that air-bricks, &c., in the floors are very necessary, and if the timbers were so dried as to be free from water (which could be done by an artificial process), the wood would only be fit for joinery purposes. Few of our readers would imagine that water forms ⅕th part of wood. Here is a table (compiled from ‘Box on Heat,’ and Péclet’s great work ‘Traité de la Chaleur’):-- WOOD. Elements. Ordinary state. Carbon ·408 Hydrogen ·042 Oxygen ·334 _Water_ _·200_ Ashes ·016 ----- 1·000 Many houses at our seaport towns are erected with mortar, having sea-sand in its composition, and then dry rot makes its appearance. If no other sand can be obtained, the best way is to have it washed at least _three times_ (the contractor being under strict supervision, and subject to heavy penalties for evasion). After each washing it should be left exposed to the action of the sun, wind, and rain: the sand should also be frequently turned over, so that the whole of it may in turn be exposed; even then it tastes saltish, after the third operation. A friend of ours has a house at Worthing, which was erected a few years since with sea-sand mortar, and on a wet day there is always a dampness hanging about the house--every third year the staircase walls have to be repapered: it “bags” from the walls.