FTER several observations Aon on the difference of places whose situation is more or less wholesome, Mr. Duhamel concludes in general, that rising grounds, and exposed to the wind, are the most wholesome; that those situate near tide, fresh or salt water, are not subject to the epidemics that infect ships; that the sea is not the cause of these epidemics; that the seamen are more exposed to them, when they anchor in roads, surrounded by mud, marshes, and sheltered from the wind; that, when their health obliges them to go on shore, they should be compelled to return on board for the night; or, if this cannot be conveniently effected, should be kept at a distance from marshy grounds, and not permitted ever to encamp, or to lie without goods tents, set up in dry, high and open places.

To discover the particular causes of infection in ships, M. Duhamel lays down this general principle: that the different qualities of the air, the vapours that humect, the exhalations that penetrate it, influence, to a great degree, the health of the animals that breathe it. Nothing but malignant vapours, or putrid exhalations in the air, can occasion those dreadful contagions that lay waste cities, and sometimes provinces. The more the air is debarred of a free circulation, the more it is susceptible of impressions from the causes that alter and corrupt it.

Now all these inconveniencies concur to infect the air in ships, especially in the hold of a ship. It there becomes thick, and its thickness does not permit the perspiration of animals that breathe it, to discuss and dissipate it. Whence it happens, that the warmth of this confined air is more sensible than that of the exterior air, and its elasticity is prodigiously weakened. It has not, therefore, that degree of condensation, that freshness, that mo tion, which makes it so favourable to respiration. This may be evinced from the accidents that happen to a bird shut up under a bell, where the air it breathes cannot be renewed. Between decks, and in the holds of ships, provisions contract heat, ferment, and send forth exhalations; of which the volume, stench, and malignity are augmented by the like produced by the dung of animals, the smell of their wool, their respiration and transpiration, and the vapours exhaled from the putrid waters in ships and in the sink, and even by the bitumen exhaled from the sea.

If the ship's crew are attacked by any sickness, the causes for infecting the air are still more multiplied. During voyages into cold, and much more into hot countries, seamen meet with new sources of disorders. The changes of air and climate are the more dangerous by their indiscretion in braving, and even provoking their pernicious impressions. Lastly, salt aliments, though less subject to corrupt, yet,

by

by being hard of digestion, bring on a multiplicity of deseases, especially the scurvy. These are the enemies M. Duhamel endeavours to destroy. He first proposes precautions against their attacks by preventing them: persuaded, that it is always easier to guard against deseases; than to cure them; or that if they cannot be entirely avoided, their violence may, in a great measure, be checked or abated.

These precautions are: 1. To admit nöne aboard; but fresh and healthy sailors, and well provided with all necessaries, in linen and cloaths, to keep themselves clean. Sick, fatigued, ill-clothed sailors are, in ships, a source of contagion. 2. To clean frequently the sick; to sweep and scrub, especially on the inside, all the upper parts of the ship, and particularly the post of the sick and cattle fold. All should be carefully washed; but this ought to be only during the heat of the day, that it may dissipate the moisture before night. Cleanliness in the sailors, and keeping the ship from all filth, infection, and every thing productive of putrid exhalations and vapours, cannot be suffi ciently attended to. 3. To purify and renew, as much as possible, the air in the hold and under decks. For this purpose are used the ventholes, the wind sleeve, bellows, and principally Dr. Hales's ventilator.

Vent-holes are only apertures, through which the infected air may escape. Some observations are necessary to direct their use. Vapours are lighter than pure air, and their levity determines them to ascend through the vent given them. This is a general principle, that regulates the form and use of all the machines for renewing the air of VOL. II.

the

ships. Therefore the vents for introducing the pure air cannot be placed too low, nor those for letting out the infected vapours too high; and if they were too narrow, vapours would find in them a friction, which must obstruct, and cannot be conquered by their levity: As to the other machines, M. Du hamel proposes some methods for making their play more easy, and their action more effectual.

Fire is another agent, which may serve the same purposes: it rarifies the ambient air, and the vapours it is loaded with. This rarefaction augments considerably their levity, and consequently accelerates their going out. Perfumes are also reckoned as a means for purifying the air of ships. The author alledges some examples of very troublesome and obstinate fainting fits, wherein the smell of vinegar alone produced the most salutary effects. This virtue he attributes less to the stimulating action of vinegar, than to the impression it produces on the air the i sick persons breathe; " For, says he, there are none but have found some pleasure in breathing the vapour of vinegar on days disposed for stormy weather; wherein the air being less fit for respiration, one is obliged to fetch frequent and profound respirations; and thus it is sufficiently proved, that it is necessary to sprinkle good vinegar between the decks, and especially in the apartment of the sick." However, it seems probable, that the effect is almost as transient as salutary; that is, that the salubrious quality communicated by vinegar to the air, is not so durable as the ease it procures to the sick.

The vapours of burning sulphur, continues our author,hinder fermen. E e

tation,

tation, and consequently corruption, even in the liquors that are most disposed to ferment, such as wine, beer, &c. It is allowed that these vapours serve to disinfect the merchandize that come from countries suspected of contagion. Those captains of ships are therefore to be commended, who from time to time, burn priming powder steeped in vinegar between decks, or who perfume the decks with vinegar poured upon a red hot-ball. M. Duhamel prefers the aspersion of vinegar to its vapour, whereof the smoak is disagreeable, and may be hurtful, if too strong; for indeed the smell of vinegar is more grateful than breathing its vapour; and he also counsels, in certain roads, when the weather is fair, to perfume with the vapourof sulphur the decks and bread rooms. Care, at the same time, should be taken to guard against all accidents of fire; and the ventilator of Dr. Hales, a bellows so powerful for pumping air, would not be less so, in diffusing the perfumes throughout all parts of the ship. If any disagreeable smell remained, it might be easily dissipated, by going about with a red-hot iron ladle, filled with aromatic drugs of little value, as juniper-berries, and such like.

From all this practical doctrine, M. Duhamel concludes, "That the hold, where the air is more corrupt than in any other part of the ship, should never be the lodgment of the sick, except in the time of an engagement. He assigns them a place where there are no hatches from the hold nor the lower deck, because the air issuing from these places is almost always very unwholsome; and advises, in a parti

cular manner, those that are in good health, to make no use of the wearing apparel and the hammocks of the sick, contagious maladies being chiefly communicated by cloaths. "In the time of a plague, it has been observed, says he, that whole families have preserved themselves from the contagion, by shutting themselves up in their houses, tho they received their provisions from infected persons, who sometimes fell dead whilst they conversed with them from their windows; whereas at the same time, a single rag would have communicated the plague. Of this, adds he, I have a very decisive proof in the contagion that destroyed so great a number of cattle m France and elsewhere. One of our farmers preserved all his cows, by keeping them shut up in a stable, and by hindering his domestics to go into infected stables, and those of his neighbours, whose cattle died, to come into his."

It is true, all those precautions for keeping ships from being infected, are an addition to the seamen's toil; but they need not be deemed such when found highly expedient for obtaining the great ends required from their service. M. Duhamel proposes likewise some substitutes to the ordinary food of seamen; but as the victualling of ships, particularly those of war, is provided for as the wisdom of a government thinks most proper, we shall not here touch upon that article.

When ships are arrived at their place of destination, M. Duhamel recommends, that their stay should be as short as possible in rivers and muddy ports, sheltered from the wind, and known to be unwhol

some.

may

may be fastened on the wearer with strings, or, if it should be thought more secure, with buckles and leather straps. This waistcoat does not weigh above twelve ounces, and be made up for about five or six shillings expence. It is more simple in its make than the bag, not liable to the inconvenience of being blown up, as is absolutely necessary to the use of the bag, nor like that, subject to be torn. Mr. Dubourg has tried his waistcoat in the Thames, and found that it not only supported him on the water, but that even two men were not able to sink him, though they made their utmost efforts for that purpose. If those who use the sea occasionally, and especially those who are obliged to be almost constantly there, were to have these waistcoats, it would be next to impossible that they should be drowned. This expedient, considered as a pleasurable article, to those who love swimming, is not contemptible, but further and greater uses may be derived from it. It would be of vast service to those, who, for their health sake, bathe in the sea, and even the most timorous and delicate young lady might boldly venture, with one of these waistcoats, into a rough sea. need not say how useful they would be to the navy, and how many lives they would save. And as we have now experienced, that the coasts of France are not inaccessible, surely these waistcoats might be of prodigious service to our men in embarking and disembarking; as it would be impossible, that even those who cannot swim, should be drowned before they could receive help from the boats. The expence of providing a sufficient number of them for our navy, can be no objec

I

1

A particular method of recovering persons that are drowned; exem- . plified in the case of a young woman who had lain some hours under water.

Tcated to the author of Jour

HIS account is communi

nal Historique sur les matieres du tems, for December 1758, by Dr. Du Moulin, an eminent physician, who accidentally, and luckily for the poor girl, happened to hear of her misfortune soon after she was taken out of the water.

A servant maid, be says, of about eighteen years of age, had fallen into the river, down which she was carried, by the force of the stream, upwards of 150 paces from the place she fell in at. But her cloaths catching hold of some piles, driven down for the use of a neighbouring tanner, she there stopt; and, some hours after, the tanner's people coming that way, she was taken up. Being personally unknown to those who first found her, she was exposed some time before her friends heard of the disaster that had happened.

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