1821.] Capt. Manby on Preservation of Shipwrecked Persons. 165

As in winter, from the greater length of the nights, assistance is more likely to be required by night than day, and it might be difficult, if the first attempt to cast the rope over the vessel failed, to lay it again in the dark with due correctness, it was necessary to supply a method, by which it might be laid with as much correctness in the dark as in the light. This was done by an oblong wooden frame, six feet long and four wide,

having at equal distances round its edge conical pegs six inches long, tapering from their base to the point, on which the rope is faked in tiers alternately along and across, as is described in the figure.

The best mode of guarding against any kinks in the rope is, that one person should turn out all the inclinations of the rope to twist and kink, and give it in to another who is faking it, only exactly in such quantities as he is able to dispose of in the fake.

The greatest care should be taken to keep the mortar dry; it should not be loaded till every thing is ready; then it should be primed and instantly fired.

But as it would be impossible to prime with loose powder in a storm, a tube (in the form of the annexed figure) may be made of common writing paper, the outer edge of which should be cemented with a little gum. This is to be filled with a paste made of finely powdered gunpowder and spirits of wine; when it is half dry, a needle is to be run through the centre of it, and the hole left open. The effect will be, that when the tube is inflamed, a stream of fire will rush with great force down the aperture and perforate the cartridge.

It having been found difficult to keep a match lighted for firing the mortar, on which all depends, a pistol was fitted up with a tin box over the lock to protect it from the wind and rain or spray (as in p. 166); the flame of which, at the discharge, is so dilated, by the barrel being cut transversely at the muzzle, as to require but little exactness in the direction of the aim. Once however the pistol got wet from being washed over by the sea, and the whole crew of a ship nearly perished in consequence. This excited me to inquire whether, by a chemical process, instant and certain ignition might not be produced; and I found that it might in various ways. I state however the following as the most simple and convenient for this particular service: Take equal parts of hyperoxymuriate of potass and the best refined sugar or sugar-candy, reduce them to an impalpable powder in a perfectly dry mortar, and let them be well mixed together. It may like

wise be made by substituting gum olibanum for the sugar. The application of sulphuric or nitrous acid to this compound will produce immediate ignition.

To prepare the powder for the particular service of firing the mortar, the following directions are to be observed: Mix so much of the powder with rainwater that has been boiled as will form, after having been well stirred, a thick fluid; crack the heads of the tubes, prepared as above described, intended to be primed with this mixture, that it may better unite with the gunpowder in them, and lay so much on the tops of the tubes as will completely cover them; then let them be thoroughly dried in the sun. Care must be taken that the tubes are always kept perfectly dry; for on this the quickness and certainty of firing depend.

To fire the tubes, wet the end of the finger or a stick with the sulphuric acid, touch the composition on the primed tube with it, and instantaneous ignition

will follow.

The sulphuric acid should be closely stopped in a glass or lead bottle, kept in an upright position, and should not be exposed to the air, but for the moment when it is used; with this care it will retain its virtues for many years.

Having furnished instructions for preparing the apparatus, it is next necessary to direct the mode of applying it to its purpose of gaining communication with a distressed vessel driven on a lee-shore. When the wind blows directly on the shore, the mortar is to be pointed directly at the vessel; any direct opposition from the strength of the wind is to be met and overcome by a proportionate increase in the charge of powder, up to the highest quantity given in the scale. But it may happen that vessels take the ground when the wind blows sidewise along the shore, or the wind may have changed after they have taken the ground, supposing them to have driven with the wind right on the shore. When this is the case, if the mortar should be fired pointed directly at the object, the rope carried out by the shot would be swept far to leeward of the vessel by the force of the wind, and communication be missed. It is therefore in a side-wind, necessary, in proportion to the strength and obliquity of the wind, to point the mortar to windward of the object; the slack of the rope carried out by the shot will then be borne by the wind so much to leeward as to fall on one part or other of the distressed vessel. In the case of a strong side-wind the lower the elevation (about the angle of 15 degrees) at which the mortar is fired, the less power the wind will have over

the

1821.] Capt. Manby on Preservation of Shipwrecked Persons. 167

the rope, and the more certain it will be to fall on the weathermost part of the gging of the wreck, with which communication is attempted.

When the rope is thrown on board, the crew, if not extremely exhausted, will at once secure it to some firm part of the wreck, and then a boat* (if a boat be at hand) may be hauled off by it: the boat is kept, by the power given over it by the rope, with its head to the waves and wind; and consequently rises over the surges, free from the danger of being upset.

If the crew, as is sometimes the case, are so benumbed or fatigued as not to be able to secure the rope themselves, the barbed shot, when the rope with which it has been projected over the vessel is drawn in from the shore, will of itself take hold and fix on some part of the rigging or hull of the wreck, and a boat may be hauled off it, although the crew are so exhausted as not to be able to move a hand towards saving their own lives.-(To be continued.)

When circumstances will permit, a boat hauled off by the rope thrown from the mortar is the method most to be relied on as the most prompt and certain mode of relief from a beach.

SELECT POETRY.

From Flatt'ry-vile delusive flow'r-
(Like Humble Plants we'll bend)
The phantom of the affluent hour,
A counterfeited friend!

And vain Conceit, with tow'ring crust,
To Vanity allied;

With meagre Envy, we'll detest,

And cast Mistrust aside!

Of Falsehood, with her stentor voice,
We'll ever be aware;

Avoid vain Pleasure's fatal choice,
And shun that viper-Care!
From Fashion's wild and giddy round,
O Luna, let's retire!

To where mild Temperance is found,
And Friendship tunes the lyre!

There, if Content her smiles impart,
And Happiness attend;

'Twill be a Sov'reign Love-desert
If Luna calls me-Friend!
July 2, 1821.

T. N.

THE