The loss of men’s lives from the foul air of the well is a common accident in ships, and I have been myself witness to several instances of it. Where there is the least suspicion of this, a candle should previously be let down, and if it should be extinguished, it may be concluded that the air is deadly. It becomes safe for men to breathe in it by leaving it open for some time, or, more expeditiously, by letting down fire in a pot or grate, which soon changes the air, by producing a draught of it upwards.
It is a very salutary practice to let down fires frequently into the well, both in order to purify the air and to dry the surrounding parts. It was formerly mentioned that this was daily done in the Intrepid, and the effect of it was to remove the wetness of the ballast and the mouldiness which had overspread the sides and beams; and having had the effect of sweetening and purifying the air, it seemed to be the principal circumstance that tended to make this ship extremely healthy from being the most sickly of all the fleet. This precaution, as well as every other point of cleanliness, is more necessary in large ships, because the mass of foul air, as well as the quantity of corrupting materials, is greater[58].
The following fact strongly evinces the good effect of fire and smoke:—When it was the custom for frigates to have their kitchens between decks, they were much more healthy than in the present construction, in which they have them under the forecastle, where the heat and smoke are dissipated without being diffused through the ship, and causing a draught of air upwards, as formerly. The men derived then also great benefit and comfort from having a large fire, round which they might assemble to warm and dry themselves in a sheltered place. I leave it to those who preside in the construction of the navy to determine how far it would be advisable to return to the old manner of construction. The French ships of the line have their kitchens and ovens between decks, and this must tend to counteract the effects of their want of cleanliness. The Dutch ships of the line have their kitchens on the orlop deck, which must be still more conducive to the general purity of the air.
Moisture is pernicious both in itself and as the instrument of putrefaction. All the complaints, called colds, are more owing to wet than cold; and moisture may be the means of producing, or at least of exciting dangerous fevers, when they would not otherwise appear. It besides contributes greatly to the production of scurvy. Ships built of ill-seasoned wood are found to be very unhealthy on account of the moisture contained in it. The moisture of timber arises not only from being used too soon after being felled, but also, as I am informed, from being stripped of its bark and outer surface when piled and exposed to the weather in dock yards. This method of smoothing and piling the wood is only a late practice; and the advantage in point of convenience and neatness seems to be more than overbalanced by the detriment it thereby receives.
A wet hold diffuses moist vapour all over the ship; and it was a rule with some of those commanders whom I observed to be most successful in preserving the health of their men, not only to have daily fires in the well, but to bail out the water when the pumps could not exhaust it all, and never to allow it to collect to more than the depth of a few inches. It is, therefore, very doubtful whether it is a good practice to let in water, as is very commonly done in order to sweeten the hold, for the same sweetness will be preserved if it is kept strictly dry. If it should happen, indeed, that there should be a great deal of putrid matter in the lower parts of the ship, from previous neglect or unavoidable leakage, it may be adviseable to let in a quantity of water in order to loosen and wash off what is offensive, and then to pump it out.
There is a circumstance in the first fitting out of a ship well worth attention, as highly conducive to the dryness and cleanness of the hold. I mean the choice of the ballast; for that which is called shingle, consisting all of pebbles, is far preferable to that which is sandy and earthy, as it does not so readily soak and retain the moisture and filth. Water or fluid of any kind readily subsides in it, and should any putrid matter be entangled in it, there will be less difficulty in washing it out.
The decks should not be washed so often when the weather is moist as when it is fine, as it will be more difficult to dry them, and more harm may arise from the moisture than benefit from the cleanness. Washing should also be performed very early in the morning, even in the best weather, in order that there may be time for the decks to become dry in the course of the day. It is after a general washing that the moveable fires, formerly described, are most proper and useful.
Every contrivance should be fallen upon to change the air in the orlop and hold. Ventilators and windsails[59] are well adapted for this purpose, and should be used as frequently and for as long a time as possible. It has also a good effect in cooling the air in the lower parts of a ship in the West Indies, to lift the gratings of the hatches, raising them on their edges, and lashing them to the staunchions. It contributes likewise to cleanliness and coolness to keep the decks as clear as possible from[60] chests and other lumber, which are in the way of sweeping and washing, and prevent also the free course of the air.
Particular attention to ventilation is necessary in frigates, for almost all that part in which the men sleep is excluded from the air, and they are therefore very uncomfortable in the West Indies unless small scuttles are cut in the sides. But if this should be objected to as weakening or endangering the ship, there is a good contrivance for the same purpose, which I met with on board of the Nymphe frigate. It consists of a square wooden pipe, of about nine inches in the side coming from between decks, running along the side of the ship, and opening over the gunwale of the forecastle. There was one on each side.