half an hour after this system of washing has been finished; and let us observe the influence of the moisture on the health of its inmates. It ought to be kept in mind, that the men have been laboring in water since half past four o'clock, with the exception of the breakfast hour; and then, their clothes had been wetted by previously drawing, carrying, and throwing water on the main and quarter decks. Under this system of cleaning the ship (let us suppose the month of December has been ushered in), we shall find, on examination, the deck and every other article below, thoroughly saturated with moisture, and in this most miserable situation will generally be found the following persons, sitting or lying on deck, and that most probably in canvas trowsers, viz. individuals resting from fatigue; the habitual drunkard taking his nap after last night's debauch; tailors, who are compelled to sit on deck professionally; seamen and marines, making, mending, or cleaning clothes; the lazy, the delicate, and those undergoing a course of medicine, are all doomed to suffer by this humid enemy, from which they cannot fly. and which has now become fixed in the decks after such constant previous application; and long before it can be dried by animal or combustible heat, it is again deemed necessary to have recourse to ablution, and so on ad infinitum.

It will appear, on reading the foregoing statement, that British seamen are in the habit of laboring in water at least three hours daily, before breakfast, and nearly double that time (twice a week) in those ships where washing the lower deck is practised; and every morning after breakfast, in other ships where sprinkling and scrubbing are deemed salutary. But, as any thing in the shape of exagge

In the West Indies and at Bermuda, polished iron surfaces and buttons become partially oxidized in a few days; while at Quebec, but yet more particularly at Montreal, some houses which have been covered with tinned plates for forty years, remain still untarnished; and scythes, &c. exposed to the open air, in that country, continue nearly free from rust till the ensuing year.

It is generally admitted, that iron has the property of decomposing water by uniting with its oxygen to form rust, while hydrogen, the other component part of water, is carried off by caloric in the form of hydrogen gas.

It would appear, however, this process does not take place rapidly, unless the atmosphere has been previously charged with marine evaporations. For to what are we to attribute the little or non-oxidizement of metal at Montreal, but to its great distance from the sea; or, in other words, from all the oceanic exhalations having been condensed on their passage hither by the tops of mountains, and immense tracts of cold desert land, over which the wind has to pass before it reaches that city.

Rain-water, in Europe, according to Margraaf, always contains traces of the muriatic and nitric acids; it would be interesting to learn, if rain near Montreal (at a distance of 500 miles from the sea) is impregnated with marine acid.

ration would defeat my purpose, I would rather be under than over the truth; and certainly it cannot be denied, that British seamen, on an average, are daily three hours employed working in water, and the remainder of the 24 hours under its pernicious influence.

Although washing the lower deck is so very hurtful to the constitution of seamen in the temperate zones, by producing a continual train of inflammatory complaints; yet it is, sometimes, far more dreadful in its consequences within the Tropics. It being generally admitted, where ablutions of the lower deck are most frequent, the greater will be the quantity of vegetable and animal matter, which finds its way into the lower department of a ship; and, consequently, the greater will be the danger of fever; admitting animal and vegetable matter in a state of putrefaction, to be its great common cause.

All vegetable and animal substances, when deprived of life, have a tendency to perform a retrograde process, and are dissipated in the atmosphere in the form of putrid gas.

In tropical climates, this process is known to be quickest, owing to the greater strength of the putrefactive agents there; which are, 1st, a high range of temperature; 2dly, a certain quantity of moisture; and, 3dly, the free admission of atmospheric air.

And it is not a little wonderful that, even by the partial abstraction of either of these destructive agents (heat, air, or humidity), we are enabled to preserve vegetable and animal substances from decay, for a great length of time.

I am aware, that the present pernicious practice of so frequently washing decks, is founded on the venerable monument of ancient custom, rather than want of attention towards the health of our mariners and it would be wonderful indeed, if there did not exist some difference of opinion between officers, respecting the best mode of cleaning a ship, as well as on every other subject.

It cannot be denied, however, that executive officers generally adhere strictly to that method of cleaning which is best adapted to give the fairest show; while, on the other hand, the surgeon usually recommends those measures, which he thinks will give him

the least trouble.

It is painful to remark, that there generally exists an unbending disposition on the part of an executive officer, to yield to the suggestions of a surgeon, however salutary his injunctions may be; partly, it is true, because this is not the source from which orders should be issued; and partly too, from a certain esprit du corps, and a belief that the customary means are preferable.

For instance, I was once in a line-of-battle ship, where the surgeon recommended dry holy stoning the lower deck, in place of

washing it. The captain preferred the latter method, and firmly persevered in it. The consequences were, that the lancet was kept going by the surgeon, to retard the ravages of inflammatory disease, occasioned by continual humidity; and the water buckets were daily kept plying on the lower deck, by the captain's orders, on the alleged principle of allaying the dust and sweetening the ship.

In the following year, the same ship was commanded by another captain, attached to the same station, and performing exactly the same kind of service. This officer happened to be one of the few who recommended keeping the lower deck perfectly dry: and such were the happy consequences of this change, that not a single case of acute disease appeared for several months, and the medium number on the sick-list did not amount to one third of that of the preceding year.

I will leave the scientific world to judge, which of the above modes ought to have been adhered to; yet, I am fully convinced, both individuals had the welfare of the ship's company equally at heart. Hence, the propriety of having certain salutary regulations made official, or so intimately blended with the service, that they cannot be deviated from. It was by having demands for vegetables and lemon-juice interwoven with forms of service, that sea-scurvy was subdued; and it is only by putting certain barriers to washing decks, &c. that the dreadful class of inflammatory diseases is now to be diminished; and it was under a hope of obtaining so desirable an object, that this Essay took its origin.

Of cleaning a Ship's Hold.

THE practice of allowing filth to accumulate in a ship's hold to a great extent before it is cleaned out, is another link in the morbid chain of humidity, by which the inmates of the lower deck are often doomed to suffer.

No rule can be laid down for cleaning a ship's hold so good, as that it must be done as often as it becomes filthy; and it follows, as a consequence, that those ships, which are most famed for having their lower decks washed, soonest acquire an accumulation of filth in their holds.

In tropical climates, we are most imperatively called on to be

After the diurnal operations of bleeding and washing were gone through, the waggish tars used to say, "Now the doctor has taken his blood and the captain given his water, they hoped the purser's steward would soon follow with their grog."

punctual in this respect, in order to prevent fever being generated by such a cause.

Again, in colder regions, such punctuality is not necessary, as cold has the power of partially arresting the process of decomposi

tion.

I am here compelled to observe, that cleaning a ship's hold is a duty that is in general carelessly performed, because it is an unpleasant part of the service, and one that leaves no external mark for approbation, like washing and scrubbing. Hence, it is usually neglected or evaded, by saying there is no necessity, until fever has commenced its ravages.

Cleaning a ship's hold, however, is genuine cleanliness, and as salutary as washing the body and putting on dry clean linen ; while washing decks may be compared to shifting oneself into wet clean clothes. It will appear rather paradoxical to assert, that an extraordinary ship for washing is always a dirty one; but when we recollect the general tendency of the operation is that of washing filth from the surface of the lower deck into the holds, through the medium of the scuttle-holes, &c. the observation then becomes less objectionable.

Of Bilge Water.

WATER is never obtained quite pure from nature, for even rain water is known to contain small traces of the muriatic and nitric acids—and, in watering a ship from spring water, it is always found to hold a certain quantity of earthy salts in solution.

When river or marsh water is used, it is constantly found impregnated with animal and vegetable exuviæ in a suspended state, undergoing decomposition. On going to sea, after being so watered, the heat and impure air of the holds, together with the motion of the vessel, soon produce a spontaneous change in the water in cask; and that oozing through the ship's sides, and these united agencies, give origin to that fetid smell, commonly said to arise from the "Bilge Water." This is, in fact, a mixture of impure sulphuretted and carburetted hydrogen gases, varying in strength, in proportion to the quantity of foreign matter contained in the water, newness and tightness of the ship and casks, and degree of heat and motion at the time.'

1 Carburetted and sulphuretted hydrogen gases are formed in the following way-When water is partially decomposed, either by being kept long in cask, or subjected to great heat and pressure in oozing through a ship's sides, the carbon of the wood unites with the hydrogen of the water, to form an impure carburetted hydrogen gas. During hot weather, and when there is great motion in a ship at sea, this gas may be collected in the well of a

Both these gases are highly deleterious to animal life, and, from their being of greater specific gravity than atmospheric air, they will not give up their residence in the lower department of a ship (where they were generated), unless dislodged in the way hereafter to be mentioned in the chapter on Dry Rot.

Of wet Hempen Cables.

THE Common practice of coiling down wet hempen cables in the tier, immediately after they have been hove in, fully saturated with moisture, is another very injurious and unskilful custom in the royal navy. First, by conveying moisture into the tier, from which a continual evaporation is kept up; and, thus, the inmates of the lower deck are not only doomed to suffer, by internal, but from all circumambient causes. 2dly. Every one who is only acquainted with the rudiments of science, must be fully aware, how much the destruction of a cable is promoted by adding moisture to the heat of the tier (the chief agents of decomposition), on a perishable article like a hempen cable.

Farther, humidity, like caloric, has a tendency to equilibrium : hence, the hammocks, men's clothes, and every article on the lower deck, absorb moisture, until they reach an equal state in point of saturation with the mean of the surrounding objects.

Should a due regard for health not be sufficient to deter us from this unsalutary practice, surely, the great expense the country is put to on that account, and the yet more important consideration of greater personal safety, ought to induce us to abandon this

custom.

Moreover, when we consider that, in many perilous situations, a cable is the only connecting link between life and death to a ship's crew, one would not, a priori, anticipate any objections to preserving it in as perfect a state as possible. I would, therefore, recommend, that cables should uniformly be allowed to dry on the main deck (except in cases where it is necessary to have it clear for action) before being coiled down in the tier.

The iron cable, from its uniformity in point of strength, and its non-absorbing qualities, possesses advantages over the perishable hempen one, both in regard to safety and salubrity, which ought not to be forgotten in comparing them.

ship's hold, by a bottle, after the same manner that gases are collected in a pneumatic trough. Sulphuretted hydrogen gas is formed thus: during the putrefaction of the animal and vegetable matter contained in water, sulphur is evolved, in union with hydrogen, to form this fetid gas.