An interesting letter, dated May 7, 1843, written by "A GENTILE," but apparently composed by a Church member, comes from the New York Herald. May 30, 1843.

LATE AND INTERESTING FROM THE MORMON EMPIRE ON THE UPPER MISSISSIPPI.-We have received very late accounts from the new Mormon religious empire, established by Joe Smith, the modern Mahomet-accounts which are very interesting and curious in a people which have attracted the attention of the public throughout the old and new world-in the Atlantic States, and the continent of Europe. Our correspondence is annexed.
By these authentic statements it appears that the holy city of the Mormons, called Nauvoo, is increasing more rapidly than ever-and that the recent efforts to persecute the prophet, and to disgrace their religion, have only resulted in more popularity-a fresh increase of converts-and further successes on land and water. New revelations and fresh predictions are also in the sack, and will soon be out. The new batch of brass plates will be the foundation of more prophecy, wonder, excitement, and increase. Joe Smith has already demolished Father Miller and the politicians, and is now preparing to issue another book of Mormon, that will wake up the world a second time. We shall wait for this development, with open mouth at least.

The following is our correspondence from the Holy City, which is quite curious and interesting:-

NAUVOO, ILL., May 7, 1843.
Rapid Increase of Nauvoo-Progress of the Faithful-New Discovery of Brass Plates-Splendid Military Review-Science-Politics.
DEAR BENNETT:-
The Spring here at last opened, after a long and very severe winter, which has brought us into May before the forest buds and the plains put on their green mantles; but lovely May is preparing the face of Nature with her usual taste; the feathered warblers begin to chirp their notes of praise, while the din and bustle of business consequent upon the rapid improvement of our city, from an aspect at once auspicious of its future glory and greatness.
About five hundred emigrants from England have arrived this spring, and it is said a number are still on their way, besides many who are daily arriving in small parties from different parts of the United States, all of whom settle in the city or its immediate vicinity. Those who have means, buy a lot of land, and build upon it immediately. Mechanics of all classes are here in abundance, who find sufficient employment to procure a subsistance, but would undoubtedly meet with a greater degree of prosperity if we had some capitalists to commence manufacturing upon a more extensive scale. I am surprised that Eastern capitalists do not turn their attention to this point; there can be no better place on the continent of America for the enterprise of those who command capital. Any amount of the best of mechanical labor can be had here at a low price-all the necessary materials for erecting and carrying on manufactures are convenient. Water power can be had to a great extent with a little expenditure-a navigable stream laving our shore, by which we can ship our surplus products cheap to the South, the North and East, besides the rapid increase of population of this place, is such as to demand the preparation for extensive manufacturing establishments to supply the demand for home consumption. Facts as they exist, warrant the conclusion that this place in five years, will be the largest city in the West, and if I was predisposed to the marvellous, I might carry out the conclusion until I had swept over the large cities of this continent, and set up a rivalry with those of Europe and Asia. Suffice it to say, in view of this city and its founder, that strange things have happened, and still things more strange may happen.
Another set of plates have been found in Pike county, in this State; they were dug out of a large mound, fifteen feet from the summit, by a company of persons, fifteen in number, who all affirm to the fact of their situation when found. There were six in number, about three inches in length, and two and a half broad at one end, and one inch broad at the other, being something of the form of a bell, about the sixteenth of an inch thick, with a hole in the small end of each, fastened together with a ring, apparantly of iron or steel, but which was so oxidised as to crumble to pieces when handled. The plates are evidently brass, and are covered on both sides with hyerogliphics. They were brought up and shown to Joseph Smith. He compared them in my presence with his Egyptian alphabet, which he took from the plates from which the Book of Mormon was translated, and they are evidently the same characters. He therefore will be able to decipher them. There can be no doubt but they are a record of some kind, buried with an individual, centuries ago; a skeleton was found with them-some of the bones in such a state of preservation as to show the size of the individual, whose height must have been eight and a half feet. You may expect something very remarkable pretty soon.
Yesterday, the sixth of May, was the general parade of the Nauvoo Legion. Gen. Arlington Bennett was expected to be here to inspect the Legion, but did not appear. The day was windy and cold, but the military spirit predominated, and the ranks were well filled; they formed and went through the evolutions out on the Prairie, about two miles from the Temple, all in good style, I expect, (as I was not out, I am unable to describe.) I had the pleasure of observing them when they came in the town in the afternoon somewhat fatigued, no doubt, but still presenting a martial appearance. An elegant band of music in front, the Lieut General, Jo Smith, and staff, next-followed by Major General Wilson Law and staff-then the Cavalry-then the Artillery-then the Infantry. The officers were well uniformed, and are fine looking men. The private soldiers (most of them) were without uniform, but are well disciplined, and ready to do good service to their country. I thought as they passed, "Who would not be a soldier?" The staffs of the two first ranking Generals, were adorned with twelve beautiful ladies mounted on elegant chargers, and if the officers of the Legion could not serve their country in the field gallantly with such aids, then the days of chivalry and knight-errantry are certainly over.
We have a number visitors here continually, some wishing to lecture on phrenology, some on phonography, some on neurology and mesmerism, thinking, I suppose, there is a fine field for their humbuggery; but fortunately for the citizens, they find men here that are able to scan the sciences, and their ability to illustrate their principles. The temple is going on rapidly; we have services on the first floor every Sabbath. The Prophet frequently addresses from five to six thousand auditors with all the eloquence and pathos which he so pre-eminently possesses.
The political parties are marshalling their forces for the August election, when representatives to Congress are to be elected. Our new district commences at our county (Hancock), and takes in all the river counties to Galena. The Mormons are supposed to hold the balance of power between the two parties, and great efforts are made by political demagogues to obtain their votes, and by some who are about as fit to represent them as Col. Pluck was to represent the militia of Pensylvania. I hope they will select a good man that will have moral stamina enough to serve them, if any such offers himself. If not, why let them run one of their own men. We are count to have dignity and importance, and to be heard in he councils of the nation. Numbers must and will be heard.
Yours, A GENTILE.

(New York Herald, May 30, 1843)