The following letter, which we have been permitted to present to the American people, in the pages of the Messenger, fills up that chasm. It belongs to an occasional correspondence, of some years' standing, between Lord MACAULAY and Hon. HENRY S. RANDALL, of New-York, author of the Life of Jefferson.

HOLLY LODGE, KENSINGTON, LONDON, May 23, 1857.

HENRY S. RANDALL, ESQ. -- Dear Sir: You are surprised to learn that I have not a high opinion of Mr. JEFFERSON, and I am surprised at your surprise. I am certain that I never wrote a line, and that I never, in Parliament, in conversation, or even on the hustings -- a place where it is the fashion to court the populace -- uttered a word indicating an opinion that the supreme authority in a State ought to be intrusted to the majority of citizens told by the head; in other words, to the poorest and most ignorant part of society. I have long been convinced that institutions purely democratic must, sooner or later, destroy liberty, or civilization, or both.

In Europe, where the population is dense, the effect of such institutions would be almost instantaneous. What happened lately in France is an example. In 1848 a pure Democracy was established there. During a short time there was reason to expect a general spoliation, a national bankruptcy, a new partition of the soil, a maximum of prices, a ruinous load of taxation laid on the rich for the purpose of supporting the poor in idleness. Such a system would, in twenty years, have made France as poor and barbarous as France of the Carlovingians. Happily the danger was averted; and now there is a despotism, a silent tribune, an enslaved Press. Liberty is gone; but civilization has been saved. I have not the smallest doubt that, if we had a purely Democratic Government here, the effect would be the same. Either the poor would plunder the rich, and civilization would perish; or order and property would be saved by a strong military government, and Liberty would perish.

You may think that your country enjoys an exemption from these evils. I will frankly own to you that I am of a very different opinion. Your fate I believe to be certain, though it is deferred by a physical cause. As long as you have a boundless extent of fertile and unoccupied land, your laboring population will be far more at ease than the laboring population of the old world; and, while that is the case, the Jeffersonian policy may continue to exist without causing any fatal calamity. But the time will come when New-England will be as thickly peopled as Old England. Wages will be as low, and will fluctuate as much with you as with us. You will have your Manchesters and Birminghams; and, in those Manchesters and Birminghams, hundreds of thousands of artisans will assuredly be sometimes out of work. Then your institutions will be fairly brought to the test. Distress everywhere makes the laborer mutinous and discontented, and inclines him to listen with eagerness to agitators who tell him that it is a monstrous iniquity that one man should have a million while another cannot get a full meal. In bad years there is plenty of grumbling here, and sometimes a little rioting. But it matters little. For here the sufferers are not the rulers. The supreme power is in the hands of a class, numerous indeed, but select, of an educated class, of a class which is, and knows itself to be, deeply interested in the security of property and the maintenance of order. Accordingly, the malcontents are firmly, yet gently, restrained. The bad time is got over without robbing the wealthy to relieve the indigent. The springs of national prosperity soon begin to flow again; work is plentiful; wages rise, and all is tranquillity and cheerfulness. I have seen England pass three or four times through such critical seasons as I have described. Through such seasons the United States will have to pass, in the course of the next century, if not of this. How will you pass through them? I heartily wish you a good deliverance. But my reason and my wishes are at war, and I cannot help foreboding the worst. It is quite plain that your Government will never be able to restrain a distressed and discontented majority. For with you the majority is the Government, and has the rich, who are always a minority, absolutely at its mercy. The day will come when, in the State of New-York, a multitude of people, none of whom has had more than half a breakfast, or expects to have more than half a dinner, will choose a Legislature. Is it possible to doubt what sort of Legislature will be chosen? On one side is a statesman preaching patience, respect for vested rights, strict observance of public faith. On the other is a demagogue ranting about the tyranny of capitalists and usurers, and asking why anybody should be permitted to drink champagne and to ride in a carriage, while thousands of honest folks are in want of necessaries. Which of the two candidates is likely to be preferred by a working man who hears his children cry for more bread? I seriously apprehend that you will, in some such season of adversity as I have described, do things which will prevent prosperity from returning; that you will act like people would, in a year of scarcity, devour all the seed-corn, and thus make the next year, a year not of scarcity, but of absolute famine. There will be, I fear, spoliation. The spoliation will increase the distress. The distress will produce fresh spoliation. There is nothing to stay you. Your Constitution is all sail and no anchor. As I said before, when a society has entered on this downward progress, either civilization or liberty must perish. Either some Caesar or Napoleon will seize the reins of government with a strong hand; or your Republic will be as fearfully plundered and laid waste by barbarians in the twentieth century as the Roman Empire was in the fifth; with this difference, that the Huns and Vandals, who ravaged the Roman Empire, came from without, and that your Huns and Vandals will have been engendered within your country by your own institutions.