Pittsburgh, February 19, 1848.

Dear Douglass:—This, probably is my last letter hailing from this quarter, and I should have been gone ere this, but Providential matters, beyond my control, have prevented.

Anti-Slavery, as such, is still a low tide in this quarter, the "almighty dollar," the over-ruling pelf, being first in thought, first in desire, and the first thing grasped at by our fellow countrymen. The Temperance cause is beginning to "look up," I having, by invitation, addressed the Pittsburgh Society of Washingtonians, on Monday evening last, in Temperance Hall, and on the following Friday evening, the Rev. Mr. West, of the Fifth Presbyterian Church, a Scotch gentleman, gave a most edifying and classic lecture, before a crowded house. One of Mr. West's strongest arguments was illustrated by a simile, in which the kidnapper, the slave-trader and the slaveholder, were the figure used for demonstration. He is an Anti-Slavery man, of the old conscientious Scotch school, and does not scruple to avow his sentiments, even in the presence of slaveocrats and Colonizationists, as there were in this instance a goodly number present. One dip more, and the old gentleman would stand unblemished in Abolition, as he now does in morality—I mean when he cuts himself loose from obligations to pro-slavery government, and above all, a pro-slavery church. His is a new school.

The Underground Railroad is in high flight, and doing a fair business here; and while I write, a panting fugitive enters my room, in company with a brother, seeking aid and advice. Of course I immediately sent the brother out for aid. He returns—a ticket is obtained—and another moment, and he is on his way rejoicing!

"Ho, the car Emancipation,

Rides majestic through our nation!"

The Whigs have another long and loud call for a candidate meeting in this city.—Scott is the choice of this call. What in the world they intend doing with all their nominees, they only know. There is also a suggestion for a Taylor meeting. It is thought that there is not much difference between the Clay and Taylorites, as the aim of both parties seem to be to support a slaveholder at all hazards. "When a house is divided against itself, it cannot stand." I am in hopes that the Whigs will stand long enough to overthrow the pro-slavery Democrats, then fall themselves, never more to rise, until this whole slaveocratic nation shall have become regenerated.

The Mexicans, it would appear, are not yet conquered; so far is this from being the case, that they, if army reports are at all reliable authority, have now in the field an army of 20,000 able-bodied men, ready to make, or receive any demonstrations which may be made upon them. It is true, there are rumors of peace, but all without the shadow of a foundation; so, without doubt, there is fighting yet to be done in Mexico;—nay, without a speedy issue of peace, the struggle is scarcely begun.

Hayti, according to foreign reports, is now in quite a prosperous condition. The President is very popular with the people, and all departments of the Government harmonize.

I see that the most infamous personage, O'Donnell, Governor of Cuba, is to be succeeded by one whose cup of iniquity, is to be hoped, will never equal in fullness that of this man. O'Donnell is one of, if not the largest African slaveholder in the world, and next to Pedro Blanco, the wretched proprietor of the slave factories on the coast of Africa, is the greatest slave trader living. Perhaps there is not a slave of the hundreds which sail out of Cuba, that is not partly owned by O'Donnell. So wealthy has he become by this infernal traffic in human beings, that the crown of Spain is alarmed at his influence over the Colony. He is the same, it will be remembered, who, when the Memorial from the World's Convention, for the abolition of slavery, went forth, invoking the immediate action of the crowned heads of Europe, and the sovereignties of the world, in aid of the great cause, declared, "that though an act were passed by the Cortes Councils, sanctioned by the Sovereign, for the abolition of slavery in the Spanish Colonies, he would never, while acting as the Chief Magistrate of that Island, permit such an act to take effect there." This stand was taken by him in an official proclamation to the slaveholders of Cuba.

It may be well, in this connection, to name the fact that Trist, who is now in Mexico, as the Representative of this Republic, endeavoring to treat with an Anti-Slavery nation, is also a slaveholder, and the same who, as the resident Consul of the U.S., endeavored his utmost to effect the re-enslavement of the Amistad captives. Trist is a fast friend of O'Donnell, and also enters, it is said, and I doubt not the report is correct, largely into the foreign slave-trade. His immediate interest is in the barracoons or slave factories of Cuba, and instead of being, as he now is, in Mexico, the representative of a nation making high pretensions to justice, he, by their own laws, the act of Congress, 1808, should be branded as a felon and pirate. If we except Pedro Blanco and O'Donnell, there is no one who is more our enemy than Mr. Trist.

The recent re-publication of the letter of the Duke of Wellington to Sir John J. Burgoyne, a Major General in the British army, respecting the dangerous exposure of the English coast to French invasion, has created quite an alarm, as well as thrown into speculation the political world. Neither is it hard, for any who at all understand political economy, especially the present history of the political world, to determine the cause, at such a time as this, when "England is at peace with all nations," and especially in friendly relations with France, of the issue of such a document by the Duke.

Louis Philippe, King of France, is certainly, in my estimation, a great politician, having a great portion of the shrewdness, with all the intrigue of Talleyrand, inheriting a greater share of duplicity than most men living. And what no monarch of France, from Louis I. to the Emperor Napoleon, was ever able to effect by political intrigue, power and the sword, Philippe is about to accomplish by duplicity, yet carried out in a manner the least to be suspected.

It is known that France has ever desired a universal mastery, as shown by the Wellington letter, having, at different periods, occupied every capital in Europe, save that of England. The extension of a royal family over different kingdoms, has, in Europe, ever been regarded as a most dangerous precedent, and more dreaded by rival powers than fleet and armies. For the consummation of a project of such mighty magnitude, the Court at Versailles has resorted to means unparalleled at least in modern ages.

This subtle monarch, who has neither the propensity nor talents for military achievements, commenced his rapid strides to power first by the crusade of his eldest son, the Duke of Orleans in 1833, upon the Northern nations of Africa, whom, with little or no resistance, he expected to subdue; and this once being effected, would give a pretext for a powerful fleet to cruise the Indian Ocean and Mediterranean Sea, and continually act as a check upon the formidable naval force of Great Britain. But contrary to his expectations, the resistance met from Abd-el-Kader foiled and baffled that great project. In the mean time, the Duke was killed by a fall from his horse, upon his own estate, near Paris.

The next effort was in 1835—a demonstration upon the Republic of Hayti—for which purpose an expedition was fitted out, of which his second son, Prince de Joinville, was the Chief, aided by Baron Lascasses, with whom it was left optional whether that demonstration should be made by treaty or bombardment.—But the Prince and Baron, having before their mind's eye the fate of General Leclerc, the greatest captain and military tactician under Napoleon, considered it no disgrace to enter into friendly negociations with the warlike Republic. Leaving Hayti, without an opportunity of testing the military skill of the Prince, the next attack was in 1836, upon Vera Cruz, by storming the Castle of St. Juan de Ulloa. In this, the squadron was quite successful, the Mexicans, under Santa Anna, being repulsed, with the loss of a leg or foot by that chieftain.

The Prince having proved his military ability, the old King, as the first link in the great chain by which the fidelity of foreign powers was to be secured to France, manages to consummate a marriage between his son, the Prince de Joinville, and Clementina, daughter to the Emperor of Brazil. This great link being welded, in order to dupe England into an indifferent observation of his rapid strides, the masterly step was to effect the union of Prince Augustus Coburg, brother to Prince Albert, husband to the Queen of England, with his second daughter. Another link being completed, he leagues in the ties of matrimony Duke de Montspensier, his third son, to Isabella, Queen of Spain.

No sooner is this effected, the last link of the great cable being complete, than the health of the "Infanta Isabella" becomes impaired, or she at all events grows very weary of public life, and a proposition at once is made to abdicate the throne in favor of her spouse, Duke de Montspensier. Of course this at once gives Spain to the Crown of France, which will thereby not only hold the key of Europe, but places Cuba, the key of the Western Hemisphere, also in her hands. The last stroke of the hammer being struck, all France being upon her feet, each officer at his station and each man at his post, Louis Philippe looking upon his success as sure, as the crowning scene in the drama, effects the appointment of Prince de Joinville to the Lord Admiralty of the Navy of France—an office of the same import and rank, but called by another name. All this is but a prelude to the design of France upon Europe. Of course England would be the first point of attack; and there is no man living more capable, and none who would so quickly discover and effectually foil the designs of the crafty and old monarch, as the invincible conqueror of Napoleon.

But are we not interested deeply in these movements? Most certainly we are. England, at present, is the master spirit of the world. Her every example is to promote the cause of Freedom; and had she possessed the same principles during the revolutionary period, in every place that she possessed slavery would have been abolished. Hence, slavery in this country could not have stood; for the slave once tasting freedom, all the powers of earth and hell could not have reduced him again to servitude.

But how with France? She is a slave-holding power, deeply engaged in human traffic, favoring and fostering the institution of slavery wherever she holds the power or influence; and with the able politician and learned statesman, Guizot, at the helm of affairs, the cause and progress of liberty would be retarded for years.

Yours, in behalf of our oppressed and down-trodden countrymen,

M. R. D.