The most usual voyage made by American ladies is across the Atlantic; and the time chosen for that voyage is generally in the spring or autumn. A winter passage is seldom attempted by ladies; and few that have tried it once are willing to undertake it a second time. To those who are preparing to traverse the ocean that separates us from Europe, we hope the following hints may not be unacceptable.

We earnestly recommend that every lady who can afford to pay the additional price, should engage, at an early period, a state-room exclusively to herself; unless, in deed , she can share it with a near relation. She will find the money well spent in securing the privacy and comfort of an apartment into which no one has a right to intrude; besides the additional space she will thus obtain for such articles as she would like to have with her in her room. No one who has not been at sea can imagine the perpetual and mutual annoyance, of being confined to the small limits of a state-room with a stranger; each incommoding the other all the time, and each feeling herself under the continual surveillance of her companion; both expected to make incessant sacrifices to the convenience of each other, and perhaps only one of them having a disposition to submit to these sacrifices; in which case she that is the most amiable is always the sufferer. We believe it to be the rule in packet-ships that the first applicant for a passage is allowed the privilege of being the last to have a stranger put into her apartment. And if the passengers are not numerous, the fortunate first applicant may in this manner have a whole state-room without the extra charge. But by offering this additional price on taking her passage, she can always secure the exclusive possession of an entire state-room.

If you have an apartment exclusively to yourself, the place of the second bed can be filled with boxes, books, etc, for which you would not otherwise have room. But as no ship state-room is large enough to contain much baggage, you should make your arrangements to wear during the voyage such articles of outside dress as will least require washing. Therefore, let all light-coloured or white dresses be packed away in the trunks that are to remain below, and not to be opened till the close of the voyage.

As ladies can have no washing done at sea, it will be well to begin with such dresses as can be worn all the passage. French silks are not good sea dresses, (even when black,) for the salt-air shrivels, spots, and turns them rusty. Dark-coloured india silks, or dark mousse-lines de laine, or merinoes, are much better. Dark chintzes, with no white in the figure, are convenient for common wear, at sea as well as on shore.

Muslin or bobbinet collars, to be worn in the ever-damp sea-air, should have no other trimming than an edging sewed on plain; as quilled or pleated frills lose their stiffening immediately. Silk neck-kerchiefs, or little shawls for the neck, will be found very convenient as substitutes for collars; and, if of white silk, they are extremely becoming. Or you may wear a broad, thick white ribbon, shaped with three diminishing pleats, to fit in closely the back of the neck, and crossed in front. Quilled or fluted cap-borders soon become limp and formless with the damp; so also do gauze or glace ribbons. Sea-caps should have borders either simply gathered or laid on plain; and their ribbons should be mantua, lutestring, or soft satin. A cap lined all through with silk of a pretty colour, will be very convenient at sea, as it not only assists in keeping the damp air from the head, but conceals the hair effectually; and there are rough days when the motion of the ship renders it impossible to arrange the hair nicely. A silk or madras handkerchief, pinned up into a sort of small turban, is sometimes worn at sea, instead of caps. They are very convenient, but only becoming to pretty ladies.

It is colder at sea than on shore; and even in summer, the atmosphere of the Atlantic is liable to be chilled for several days by the vicinity of floating icebergs, - even when these icebergs are not seen. Therefore, be careful at any season, to have in your state-room a sufficiency of warm clothing. A spring-passage is generally colder than an autumn one; and even in May it is sometimes found necessary, when on the open ocean, to dress as if it were winter. Flannel, of course, is indispensable; so, also, is a large thick woollen shawl, and a second shawl of lighter texture for mild weather. A very convenient outside sea-dress is the garment or coat that is sometimes called a mandarine. It should be made of very dark India silk, which is soft, strong, and not liable to stain or spot like the silks of Europe. This dress should be very long and wide; wadded and lined all through; and made with large, loose sleeves, large sleeve-holes, and a wrapper-body, confined at the waist by a broad ribbon run into a casing, and tied in front. A mandarine can be put on over another dress without rumpling it; and is far better than a cloak, as it is warmer and more compact, sits closer, and is not so liable to be blown about by the wind. At sea, there are always days when a mandarine will be found very comfortable to wear, even in the cabin.

No dress intended to be worn on a voyage should fasten behind, as it is not always that a lady can procure the assistance of another person to do this for her. Gowns, (or coat-dresses, as they are frequently called,) such as fasten in front, are the best habits for sea; and there is now a well-known way of making wrappers that is both handsome and convenient, and universally becoming. Fortunately, corsets are now exploded; and as they are no longer worn on shore, of course no one would be so absurd as to endure them at sea. Jackets of flannel, lined silk, thick cotton, or jean, made without whalebones, and to fasten in front, are best suited to a voyage. A flannel gown and a dark double-wrapper are indispensable in case of sickness. Your upper petticoat should be of dark linen, worsted, or silk. If you have no mandarine, take with you, by all means, a wadded silk petticoat, and a pair of slightly-wadded silk inside-sleeves, to be tied in beneath your gown-sleeves in chilly weather. For this purpose, have four tapes sewed to the top of each sleeve, at equal distances, and four corresponding tapes sewed to the inside of each arm-hole of your gowns.

The best sea-stockinsrs are those of substantial, un-bleached cotton. No others are so comfortable. Dark satin-ribbed cotton stockings are also good; so are the black raw silk, such as are shaggy inside. Take with you some very thick gray yarn stockings, to put on when your feet are cold in bed, and to draw on, occasionally, over your shoes and other stockings. Gaiter-boots, and boots lined with fur, are very comfortable when once on; but at sea, there is often some trouble in lacing- or button-ing them. Shoes worn on ship-board should be thin-soled and roomy, so that you may walk the deck easier, and keep your feet belter when the vessel rolls. Shoes of wadded silk are very pleasant at sea; so are Indian moccasins, or carpet moccasins lined with wool. Take with you two or three pairs of woolly sheep-skin soles, such as are coated on the under side with india-rubber varnish. They are warm, dry, and water-proof; can be slipped into your shoes or taken out, as occasion may require; and either for sea or shore, are far superior to the cork soles also in use.

A sea-bonnet should have a deep, close front, and a cape or ruffle at the back of the neck. The complexion is always liable to be injured by the salt air, the glare of the sun, and the bleak wind. A qudted close bonnet of dark silk or satin, lined with pink, blue, or leraon-colour, may be made to look very pretty. Cane or whalebone being very apt to break in the wind, it is best to run wired-satin piping-cord into the cases of a sea-bonnet, and round the edge. This will stiffen it sufficiently; and being very elastic, will keep it in shape without danger of breaking. These bonnets should, by all means, have a large wadded cape attached to them. At sea, it is important to keep the back of the neck always covered, for its exposure to the air may produce rheumatic pains in the head, shoulders, and face. Even in the cabin, and at all times when on ship-board, (except in decidedly warm weather,) it is prudent to wear a handkerchief of silk, cashmere, or velvet, tied or pinned round the neck, with a corner covering it closely behind.

Provide yourself, also, with a pair or two of warm gloves. On days when fire is most needed, it is most difficult to have it in the cabin of a ship. If the wind is strong, it impedes the draught of the stove, and fills the cabin with the smoke that is beaten down the chimney. And if the vessel rolls much, (as she always will in rough weather,) there is danger of the fire falling about the floor; and to prevent accidents from this cause, it is deemed safest to extinguish it entirely, or else not to kindle it at all. The passengers must depend chiefly on their clothing for warmth enough to make them tolerably comfortable, - particularly if they cross the ocean early in the spring or late in the autumn. But, as we before observed, a spring-passage is always the coldest. In the autumn, there is no danger of meeting with icebergs. Also, the ocean-water still retains a portion of the warmth communicated to it by the summer sun; while, in the spring, it remains a long while chilled from the cold of the preceding winter.

As dressing on ship-board is always more or less troublesome and inconvenient, on account of the motion of the vessel, and must generally be done in a sitting posture, it is well to make one dressing suffice for the day.

When packing to go on board, select such articles as are indispensable for use during the voyage, and put them all into one trunk, which must not be too large to keep in your state-room. You will find drawers there, in which you can place your caps, collars, handkerchiefs, and other light articles. Have a strong linen clothes-bag, with a drawing-string at the top, to hang up on one of the pegs or hooks in your apartment. The remainder of your baggage must be put below, in the place appropriated to stowing away the trunks of the passengers, with the understanding that they are to remain there all the voyage.

However pleasant you may find it to stay on deck, it is best, as soon as you get on board, to go to your stateroom, and make your arrangements there, lest you should be rendered incapable of doing so by the approach of seasickness; an event that may usually be expected within an hour after the vessel gets under-way, if she sails from New York or Boston, or any port in the vicinity of the ocean. Take out of your trunk your night-clothes, your easiest slippers, and whatever articles you may require for immediate use; and place them where they can be directly accessible.

Some few ladies, as well as gentlemen, cross the ocean without being in the least troubled with sea-sickness; and very many only suffer from it during the first two or three days, and are then perfectly well during the remainder of the passage, however stormy it may be. If you should incline to be sick, it will be nearly useless to struggle against it the first day or two. You may try as a preventive, or as an early remedy when the first symptoms come upon you, a lump of loaf-sugar placed in the bottom of a wine-glass, with just as much brandy poured on as will be sufficient to dissolve it, so that it can be eaten with a tea-spoon. If taken in time, this frequently succeeds; and it rarely fails in the short sickness that is sometimes felt in excursions down in the bay of New York; or in Boston harbour, when the water is rough; or in going round Point Judith; or in a trip by sea to any of the coast bathing-places.

If you find your sickness increasing, give up to it lor a day or two; and you will afterwards feel much the better for it. For the first two days you need take no nourishment but chicken-water. Avoid lemonade, oranges, all other acids, and every sort of warm drink. Be careful, while you are sick, not to taste any thing that you may like to eat afterwards, as it will give you a disgust to it during the remainder of the voyage. For the same reason, it is well not to use cologne-water, or any very fine perfume during your sickness. Liquid camphor, sprinkled over the bed and floor, will be found more refreshing and purifying to the atmosphere than any thing else that you can take with you.

The third day (if not before) you ought to make every possible exertion to go on deck, as you will be losing strength by remaining in bed; and as long as you keep your head in a recumbent posture, you will not become accustomed to the motion of the vessel. Also, on the third day, endeavour to eat a small portion of solid, relishing food - such as a piece of broiled ham, or the lean of salt beef, with a slice of dry toast. We have known what is called the tone of the stomach restored after sea-sickness by a little of the sailors' salt beef and biscuit. Something of this sort is always more effective than light or delicate food.

It will be well before you embark, to provide yourself with a box of that excellent medicine known as Lady Webster's (or Lady Crespigny's) pills. They are called by both names; probably because both these ladies patronized them in England. You may take one every night immediately after supper. In Philadelphia they are made according to the best recipe by J. C. Turnpenny, druggist, corner of Spruce and Tenth streets.

You may find a clay-ball for the removal of grease spots very useful to keep in your room; as, when the ship is rolling, greasy substances are frequently spilt on dresses.

Take with you and keep always in your apartment, a life-preserver, in case of being wrecked in sight of land; and it may really save your life by buoying you up, and floating you to the shore. It is said that a man's hat, laid brim downwards, and tied up in a shawl or pocket-handkerchief, and then fastened round the waist, will keep a person above water long enough to prevent drowning, if not far from the beach. The ladies of New York and Boston, and of other cities on the sea-board, have it in their power to learn, without danger or difficulty, the art of swimming; by subscribing to the saltwater baths, and visiting them daily during the summer. Nothing will make a sea-voyage seem shorter or less monotonous, than to be well provided with occupation - such as amusing and interesting books, and a due portion of needle work or knitting. By all means take with you one or more blank-books for the purpose of noting down whatever you may wish to remember. If you can keep a regular journal, so much the better. Also, the first day that you are able to write after getting to sea, commence on a large sheet of paper, a letter to one of your relations or friends, having previously folded and directed it. Write but a few lines at first; and every day add a little more to it, giving the fresh dates. It will always be ready (requiring only a wafer to seal it) in case you should have an opportunity of sending it by any vessel you may chance to meet, on her way to the land you have left. If no such chance offers during the voyage, this diary-letter will at least be ready to transmit with those you write home directly after arriving at your destined post. And your friends will be glad to have this concise transcript of your sea-life.