The Harvard Union.

A mock convention will be held tonight to nominate candidates for the presidency of the United States. There will be a roll call of States, and the principal candidates will be nominated when their States are called. The nominating speeches for the chief candidates will be made by speakers who have been chosen for the occasion, and will not exceed ten minutes each. Then speeches of five minutes can be made seconding previous nominations or nominating candidates not hitherto brought forward, and all members of the University are invited to speak.