A letter from London says, "The Convention at Paris have been notified, by our rulers, that if the French armies violate the rights or territories of Holland, which Great-Britain is bound by treaty to aid Holland in securing, that aid will be afforded. This notice was dispatched by a messenger in ordinary, no public functionary having been sent from this fountain of royalty to that resolute rabble of republicans, as they are called here. The answer of the Convention is said to be very blunt, direct and uncourtly. Meanwhile assurances of support have been announced, by the British minister at the Hague, to their High Mightinesses the States General of the United Netherlands, and this nation is arming with vigour by sea and land. It requires, however but little observation, and acquaintance with men and things here, to discern, that the great body of the people are not quite so fond, as the Court is eager, to engage in hostilities on the Continent--But I do really think no unprejudiced bystander, in Britain, can avoid noticing how much the private passions of this Court prevail, and are substitutionary for an honest zeal for the public welfare, and a pursuit of the solid interests of this Empire. At the same time it cannot be denied, that many British magistrates, merchants, manufacturers and untitled individuals, of all parties, sects and persuasions, feel much abhorrence of the rights of man, stripped naked of the pomp of peerage and the gewgaws of Monarchy. The truth is, that the fundamental laws of this realm--the habeas corpus act--the trial by jury--the uncorrupt conduct of the judges in all matters of meum and tuum--secure to every quiet subject, advanced one step beyond indigence, such a certainty of civil freedom, and such protection to private property, that he is contented to live without enjoying his just proportion of political liberty, and loves what is called the British Constitution. It has these its immediate effects. with all the honest, blindfold passion, that converts its blemishes into beauties. But be this so or not, it is certain that an abhorrence of Paine's doctrines, and of the popular excesses in France, and a dread of any sedition in this realm, that might render private property insecure, have excited such a flame of loyalty here, among all ranks of men, that it is at present really imprudent and unsafe, in any circle whatever, to utter a republican sentiment. John never before so much disrelished the name of liberty nor submitted himself at the shrine of royalty with such an idolatrous rage for the servitude of its ritual--never, never. The minister may, and I suppose therefore will, urge havoc, and let slip the dogs of war, against France Indeed, war, Since the negotiation of the Scheldt business, is deemed inevitable: In idea, already, all the French West-Indies and British property, and the naval power extinct. But the thing is much more easily said than done The Jacobins,identified with the millions of France, will now go all lengths, and take all chances, for all things. They have begun by confiscating a mass of property belonging to the emigrants, that is computed at a fifth of their total territory : This alone will sustain an immense force for some time. They have decreed an abolition of royalty. The Convention will certainly decapitate the King. In one word, there are blows about to be struck, that will be felt in every quarter of the globe."