The Cuban Junta-We have received the following manifesto of the Cuban Junta in this city. It strikes us as premature, to say the least, since the independence of Cuba is by no means secured by the landing of Gen. Lopez:

New-York, May 25, 1850.

To the Editor of The Tribune:

Gen. Lopez, at the head of a handful of valiant patriots, has already landed on the shores of Cuba, engaged in the glorious undertaking of liberating his brothers from the hard and hateful slavery to which they have been reduced by the brutal Government of Spain. The first step of Gen. Lopez has been marked by victory; the genius of Liberty will follow him; the God of Justice will protect him. Gen. Lopez, surrounded by the Cubans, must consummate his glorious work.

The Junta which promotes the interests of the Liberty of our country, reassembled to-day, on account of the favorable news received from Cuba, and has determined to manifest to the members of the American Press the gratitude of all good Cubans; because they are fully convinced of the liberal sentiments of those who on all occasions have declared themselves in favor of the people of all countries where the cry of Liberty has been raised, as in Mexico, Colombia, Greece, Hungary, Italy, &c, &c. They have, at the same time, resolved to express their confidence that under these circumstances, in the very moment when Cuba needs most their sympathies and help, they will continue to advocate our cause which is the holy cause of America, of Justice and all Humanity.

I have the honor to be, respectfully yours,

M. T. Tolon, Secretary.