...e to ascertain how many cannon the rebels have thrown into the Mississippi, supposing that in so doing they would render them useless to us. Lieut.-Col. Hogg, of the Second Illinois cavalry, from Paducah , in company with two hundred and fifty men, was the first to enter the enemy's works at five o'clock yesterday afternoon. Our gunboats and transports reached this place at eight o'clock to-day; b...