[** The deck immediately above the hold.]
But the most obvious use of the portable fires was their drying up the moisture, and especially in those places where there was the least circulation of air. This humidity, composed of the perspirable matter of a multitude of men, and often of animals (kept for a live-flock) and of the steams of the bilge water from the well, where the corruption is the greatest; this putrid moisture, I say, being one of the main sources of the scurvy, was therefore more particularly attended to, in order to its removal. The fires were the powerful instrument for that purpose, and whilst they burned, some men were employed in rubbing hard, with canvass or oakum, every part of the inside of the ship that was damp and accessible. But the advantage of fire appears no where so manifest as in cleansing the well; for this being in the lowest part of the hold, the whole leakage runs into it, whether of the ship itself, or of the casks of spoilt meats or corrupted water. The mephitic vapours, from this sink alone, have often been the cause of instantaneous death to those who have unwarily approached to clean it; and not to one only, but to several successively, when they have gone down to succour their unfortunate companions: yet this very place has not only been rendered safe but sweet, by means of an iron pot filled with fire and let down to burn in it.
When, from the circumstances of the weather, this salutary operation could not take place, the ship was fumigated with gun-powder, as described in the Paper; though that smoke could have no effect in drying, but only in remedying the corruption of the air, by means of the acid spirits from the sulphur and nitre, aided perhaps by some species of an aerial fluid, then disengaged from the fuel, to counteract putrefaction. But as these purifications by gun-powder, as well as by burning tar and other resinous substances, are sufficiently known, I shall not insist longer on them here.
Among the several means of sweetening or renewing the air, we should expect to hear of Dr. Hales's _Ventilator_. I must confess it was my expectation, and therefore, persuaded as I was of the excellence of the invention, it was not without much regret that I saw so good an opportunity lost, of giving the same favourable impression of it to the Public. If a degree of success, exceeding our most sanguine hopes, is not sufficient for justifying the omission of a measure, deemed one of the most essential for attaining an end, I would plead in favour of our worthy brother, that by a humiliating fatality, so often accompanying the most useful discoveries, the credit of this ventilator is yet far from being firmly established in the navy. What wonder then, if Captain Cook being so much otherwise taken up, should not have had time to examine it, and therefore avoided the encumbering his ship with an apparatus, he had possibly never seen used, and of which he had at best received but a doubtful character? Nor was he altogether unprovided with a machine for ventilation. He had the _Wind-Sails_, though he hath not mentioned them in his Paper, and he told me that he had found them at times very serviceable, and particularly between the Tropics. They have the merit of taking up little room, they require no labour in working, and the contrivance is so simple that they can sail in no hands. But their powers are small in comparison with those of the ventilator; they cannot be put up in hard gales of wind, and they are of no efficacy in dead calms, when a refreshment of the air is most wanted. Should there be any objection to the employing both?