London, May 31, 1848.

Dear Sir,—In my last letter, I mentioned that Mr. Mitchell, the editor of the "United Irishman," was undergoing his trial for felony under the recently passed "Crown and Government Security Bill." The jury having returned a verdict of "guilty," he was sentenced to fourteen years' transportation, and was, next day, after a very affecting farewell interview with his wife and family, taken, under an escort of dragoons, on board a ship bound for Spike Island, near Cork, there to await the sailing of a convict vessel. The scene in court at the passing of sentence, was most extraordinary. From all quarters of the court, people pressed forward to shake hands with him, some threw bouquets of flowers, barristers in their sober gowns and wigs, jumped over the table, in order to give a last expression to their sympathy with the prisoner; the judge who passed sentence, hastily left the bench, but returned in a few minutes, while the other who remained, could not conceal his emotion. Several persons were taken into custody for these manifestations, which were considered a contempt of court; but were shortly after liberated. Mr. Holmes, Mr. Mitchell's counsel, who had defended his client, merely on the principle that the English government in Ireland being an usurpation, it could not be wrong to wage war, or to excite to war against it; and then said, that every word he had uttered, as Mr. Mitchell's advocate, was the expression of his own deliberate conviction, for which he was individually responsible, and that the Attorney General might prosecute him if he chose. The judge immediately called upon the court to proceed with other business. Feeling strongly, as I do, the bitter wrongs and oppressions under which Ireland has so long groaned, it is impossible for me not to sympathize even with those whom a similar feeling has goaded on to madness or to crime. Without, therefore, defending Mr. Mitchell, whose grand aim in all his writings, was to prepare Ireland for an armed revolt against the government, there can be no doubt that the British government is the first and great criminal. Seven out of nine millions of the Irish, are Roman Catholics; yet not a single Roman Catholic was allowed to sit on Mr. Mitchell's jury. Every Irishman is either a Repealer or an Anti-repealer; the majority, it cannot be doubted, are Repealers; yet the government would not allow, and they avow it, a single Repealer to sit upon the jury; so that Mr. Mitchell's jury was composed entirely of his enemies. The government could not find, if they had wished it, an indifferent jury; they dared not try him by one impartially selected. This fact alone is sufficiently conclusive evidence that Ireland is the victim of an unjust and oppressive government.

It is pleasant to turn from the contemplation of these scenes of injustice and consequent rebellion, to the first annual meeting of the British branch of the League of Universal Brotherhood, which was held last night in the Hall of Commerce, and was most numerously and respectably attended. Elihu Burritt, who is for the present Corresponding Secretary, read an eloquent report, full of the poetry of his benevolent and world-embracing heart. It contained two eminently practical suggestions—the first, an Ocean Penny Postage, which would infallibly increase to a wonderful extent, the number of fraternal communications between foreign lands; the other, a Congress of Nations, for the settlement of international disputes. In behalf of this latter eminently practical object, a convention is proposed to be held in Paris, which is the place most appropriate for the commencement of a movement of that kind, on account of the understood favorable disposition of Lamartine to the plan. With regard to the Ocean Penny Postage, there was a statement in Elihu Burritt's report, which ought to receive the immediate attention of our government. All letters from America are subject to a postage of a shilling, payable in this country. During the late famine in Ireland, many Irish residents in the United States, under the influence of most praiseworthy feelings, sent home money to their friends in Ireland; but there can be no doubt, that very many of the letters containing advices of these remittances, were lost to the parties to whom they were addressed, in consequence of their inability to pay the postage. The present postage of letters to America, is one shilling, including both inland and ocean carriage. Mr. Burritt's proposal is, that there should be a charge of a penny for inland postage, and a penny for ocean postage, so that it would require only six times the present number of letters to pay the same amount of postage. There seems no reason to doubt, that the change could be made without any loss to our revenue; and, as it would be an incalculable benefit to all parties resident in either country, and having friends in the other, all persons on your side of the Atlantic, having friends here, should urge upon them the duty of assisting in the attainment of so great a boon.

The recent outbreak in Naples appears to have been of a most serious description; at all events it was made so by the brutal or much worse than brutal conduct of the King, who let loose the lazzaroni on the respectable inhabitants of the town, a great part of which was consequently burnt to ashes. The horrid scenes which took place, have roused the indignation of all Italy, and the King of Naples is everywhere denounced as a monster and a Bourbon, who has forfeited every claim to his throne, and to the toleration of society.

Yours truly,

R. S. D.