A party of four adventurous gentlemen--Mr. Louis Bucha, merchant; Dr. Bradshaw, dentist; Mr. Brackett, distiller; and Mr. Patchin, miner — arrived in this city on Saturday last from the town of Mesilla, in the Territory of Arizona, after a voyage of two months down the Rio Grande. Teh party left Mesilla on the 29th day of June last, and have been on the river ever since, without stopping at any place more than a day until they arrived at Davis ranche, where they stopped four days.

The experiment of navigating the Rio Grande from El Paso, fifty miles this side of Mesilla, has often been talked of, but no person has heretofore performed the hazardous undertaking. The gentlemen who arrived here on Saturday were solely prompted to the voyage, which they have so successfully accomplished, by the desire to do what so many had talked of, and which was pronounced an impossible journey. At present considerable bets are pending in Mesilla on the result of the undertaking, and many promises of reward will have to be fulfilled by the public-spirited citizens of that place towards the successful voyagers.

The party first constructed two willow canoes, which they lashed together and loaded with their provisions and baggage. In the next place, they erected about the sides of their raft a breastwork of hides, to protect them from the Indians, who were the first danger of which they were warned. Thus fitted out, the party started upon their novel trip. They floated along with the current, using the paddles but little, and directing the course of their raft with a rudder. They travelled during the day only, always making fast to the shore and camping on terra firma at night to avoid accidents in the river.

The Rio Grande did not treat the party roughly until they came within sixty miles of Eagle Pass, where, in descending the falls in the river, the raft upset. The water was not sufficiently deep, however, to swamp their baggage, consequently they soon righted themselves at that place. A short distance this side of Laredo, the raft capsized and in descending some falls, but without loss. At what is known as the Ten-Foot Falls, near Roma, the raft capsized, for the third time, and the party lost all their baggage, and Dr. Bradshaw lost a valuable set of dental instruments. These falls are commonly understood to be a solitary fall, where the river precipitates itself over a shelf ten feet high; but Mr. Bucha corrects this report, and says that there are three falls at that point, two of which are ten feet high, and one of which is only five feet.

It is the impression of the gentlemen composing the above party, that it will never be practicable to navigate the Rio Grande above the Ten-Foot Falls; as the current of the river is not only very strong, but the depth of water is very inconsiderable, and the bed of the river is interrupted by frequent falls and ledges of rocks which no rise of water will suffice to overcome.

The impression which widely obtains that there is a point in the Rio Grande, above Laredo and below Eagle Pass, where the river entirely disappears under the mountains, is incorrect, and the gentleman with whom we conversed accounts for it thus:--One or two parties have started from El Paso to descend the Rio Grande, but they have all failed at a point below Eagle Pass, where the mountains approach up to the water's edge, and where the bed of the stream is very rugged and the current very swift. At this point all other expeditions have failed, and from the place where their boats capsized, looking down the stream to where the cliffs beetle over the stream, which makes a sudden bend, the appearance of the scene seems to indicate that the projecting cliffs overlapped the river and forces the Rio Grande to make its way under the overhanging mountains. But this is found to be a delusion in descending the river, as the stream only makes a sudden bend and continues its rough and muddy course between instead of under the mountains.

Wild game — such as deer, turkeys, rabits, and birds abound on the river, and even if the voyagers had not found settlements every hundred or hundred and fifty miles, they could have subsisted themselves very well on what wild animals they could have killed on the river bank. The land in many places is good.

Speaking in general terms, the gentlemen express their entire satisfaction with the trip, and would have no objection to going over the route again.

It is unnecessary to specify examples from the wars of the French Revolution; the whole history of these wars is one continued proof of the superiority of fortifications as a maritime frontier defence. The sea-coast of France is almost within stone's throw of the principal British naval depots; here were large towns and harbors, filled with the rich commerce of the world, offering the dazzling attraction of rich booty. The French navy was at this time utterly incompetent to their defence, while England supported a maritime force at an annual expense of near ninety millions of dollars. Her largest fleets were continually cruising within sight of these seaports, and not unfrequently attempting to cut out their shipping. "At this period," says one of her naval historians, "the naval force of Britain, so multiplied and so expert from long practice, had acquired an intimate knowledge of their (the French) harbors, their bays and creeks; her officer knew the depth of water, and the resistance likely to be met with in every situation." On the other hand, these harbors and towns were frequently stripped of their garrisons by the necessities of distant wars, being left with no other defence than their fortifications and militia.--And yet, notwithstanding all this, they escaped unharmed during the entire contest.--They were frequently attacked, and in some instances the most desperate efforts were made to effect a permanent lodgement; but in no case was the success at all commensurate with the expense of life and treasure sacrificed, and no permanent hold was made on either the maritime frontiers of France or her allies. This certainly was owing to no inferiority of skill and bravery on the part of the British Navy, as the battles of Aboukir and Trafalgar, and the almost total annihilation of the French marine, have but too plainly proven. Why, then, did these places escape? We know of no other reason than that they were fortified, and that the French knew how to defend their fortifications. The British maritime expeditions to Quiberon, Holland, Boulogne, the Scheldt, Constantinople, Buenos Ayres, etc., sufficiently prove the ill success and the waste of life and treasure with which they must always be attended. But when her naval power was applied to the destruction of the enemy's marine, and in transporting their land forces to solid bases of operations on the soil of her allies, in Portugal and Belgium, the fall of Napoleon crowned the glory of their achievements.

Let us now examine the several British naval attacks on our own forts, in the wars of the Revolution and of 1812.

In 1779, Sir Peter Parker, with a British fleet of nine vessels, carrying about two hundred and seventy guns, attacked Fort Moultre, in Charleston harbor, which was then armed with only twenty-six guns, and garrisoned only by three hundred and seventy-five regulars, and a few militia. In this contest the British were entirely defeated, and lost, in killed and wounded two hundred and five men, while their whole two hundred and seventy guns killed and wounded only thirty-two men in the fort. Of this trial of strength, which was certainly a fair one, Cooper, in his Naval History says: "It goes fully to prove the important military proposition, that ships cannot withstand forts, when the latter are properly armed, constructed and garrisoned." Gen. Moultrie says only thirty rounds from the battery were fired, and was of opinion that the want of powder alone prevented the Americans from destroying the men-of-war.

In 1814, a British fleet of four vessels, carrying ninety-two guns, attacked Fort Boyer, a small redoubt, located on a point of land commanding the passage from the Gulf into the Bay of Mobile. This redoubt was garrisoned by only one hundred and twenty combatants, officers included; and its armament was but twenty small pieces of cannon, some of which were almost entirely useless, and most of them poorly mounted "in batteries hastily thrown up, and leaving the gunners uncovered from the knee upward," while the enemy's land force, acting in concert with the ships, consisted of twenty artillerists, with a battery of two guns, and seven hundred and thirty marines, Indians, and negroes. His ships carried five hundred and ninety men in all, This immense disparity of numbers and strength did not allow to the British military and naval commanders the slightest apprehension "that four British ships, carrying ninety-two guns, and a land force some what exceeding seven hundred combatants, could fail in reducing a small work mounting only twenty short carronades, and defended by a little more than a hundred men, unprovidedalike with furnaces for heating shot, or casements to cover themselves from rockets and shells." Nevertheless, the enemy was completely repulsed; one of its largest ships was entirely destroyed, and eighty-five men were killed and wounded on board the other; while our loss was only eight or nine. Here a naval force of five to one was repelled by the land battery.

Again, 1814, a barbette battery of one fourteen pounder and two eighteen-pounder guns at Stonnington, repelled a British fleet of one hundred and thirty-four guns. During the engagement the Americans exhausted their ammunition, and spiked their eighteen-pounders, and only one of them was afterwards used. Two of the enemy's ships, carrying one hundred and twelve guns, were engaged during the whole time of attack, and during much of this time bombarded the town from a position beyond reach of the land-battery. They were entirely too far off for the four-pounder guns to be of any use. Supposing the two eighteen-pounders to have been employed during the whole action, and also all the guns of the fleet, one eighteen-pounder on land must have been more than equivalent to sixty-seven guns afloat, for the ships were so much injured as to render it necessary for them to withdraw. The British loss was twenty killed and more than fifty wounded; ours was only two killed and six wounded.

The fleet sent to the attack of Baltimore, in 1814, consisted of forty sail, the largest of which were ships-of-the-line, carrying an army of over six thousand combatants. The troops were landed at North Point, while sixteen of the bomb-vessels and frigates approached within reach of Fort McHenry, and commenced a bombardment which lasted twenty-five hours. During this attack, the enemy threw "fifteen hundred shells, four hundred of which exploded within the walls of the fort, but without making any impression on either the strength of the work or the garrison," and the British were compelled to retire with much loss.

In 1815, a squadron of British ships, stationed off the mouth of the Mississippi, for the purpose of a blockade, ascended the river as high as Fort St. Philip, which is a small work capable of an armament of only twenty guns in all. A heavy fire of shot and shells was continued with but few and short pauses for nine days and nights; but making no impression either on the fort or garrison, they retreated to their former position at the mouth of the river.

--In the London Lancet, of August 10th, we find the report of the microscopical and chemical analysis of forty-eight samples of tea.

Of the twenty-four specimens of black tea analyzed, every one was found to be genuine. Of the like number of green teas all were adulterated. The adulterations are mainly a coloring matter with which the tea leaf is faced, painted or glazed. Ferro cyanide of iron or Prussian blue, is the article most commonly used for this purpose. Sometimes, however, indigo, kaolin, or China clay, and turmeric powder were found in addition. That species of tea which is denominated gunpowder, is adulterated in other ways by admixture with leaves not those of tea, with paddy husk, and particularly with "lie tea," so called, a leaf which resembles the tea leaf closely, and is sent to this country from China in vast quantities, to be employed in adulterations here. The coloring of the tea is almost entirely done in China, and probably because it improves its appearance, and perhaps renders its sale more sure and rapid.

Such is the result of a thorough analyzation of this article by eminent scientific men in England, and it is certainly not very flattering to the taste of those who drink green tea for the love of it. There is no such article as an unadulterated green tea. Let the lovers of the herb remember that fact, and as they sip the delicious beverage, and fancy they find in it a solvent for their aches and pains, let them also remember that they are sipping with it a solution of Prussian blue and indigo, as well as sundry other little peccadilloes, that neither add to its exhilarating properties, nor yet are entirely harmless to the system. On the other hand, the black teas are not adulterated, and are the only ones used by the Chinese. Knowing the impurities that are in the best green teas, they send them to foreign ports to tickle the delicate palates of the English, the French, and the Americans, who, in their view, fancy the bright, lively appearance imparted by the coloring compositions they use. The remedy for these wholesale adulterations is easy. It is entirely in the hands of the tea merchants. If they refuse to buy the poisoned leaf, the Chinamen will very quickly stop adulterating it.