“The Prettthak Case at Davenpout. —Uudfer this head tlio Dubuque Herald devotes three-fourths of a column of editorial to ii hash of falsehood and nonsense glorifying over the re-appointment of Mr. R. M. Prettyman as Agent of the Northern Line in this city. As the Gazette is especially aimed at by this balderdash, n few words from us arc in order.1. No one in Davenport, nor any one in Rock Island, or vicinity, knew of or dreamed of the nocturnal visits to Mr. Prettyman’s house, before it had actual!}- been made nml results made .known, except Col. Johnson, Lieut. CojL Carrahcr and the two spies; as was proven by the testimony on which Mr. Prettyman was arrainged before the military authorities. That well attested fact disposes of one batch of Herald lies.2. Mr. Prettyman received and aided the supjwsed relels (one ofthem really a rebel)because he was himself lt;' Mil id hmrl, anil * •had long been doing all he could and dare to aid the enemies of his country. That fact answers the Herald's “Good Samaritan” bosh.8. The extent of the Gazette’s “ demand” was that the Northern Line should, as it certainly ought, select a loyal man to set as its Agent in this city ; instead of compelling its patrons to transact business through a man under bonds to refrain from aiding rebels, and acting under a compulsory oath of allegiance.4. The “ principal men of Davenport” did not petition for Mr. Preltyman’s retention. A few copperheads did, and coaxed the names of a very few loyal men to their document.5. No petitions .for' Mr. .Prettyman’s removal were attempted or necessary. His disloyalty was a matter of public notoriety and Governmental record. If with these facts before them the Northern JLine chose to brave public sentiment Und outlaw .loyalty, theirs was the responsibility.; no one was going to bey llie 'Company into regard for loyalty and decency.6. The, Northern Line has simply dodged the issue presented to it. It has endeavored to atone for Mr. Pretty man's retention by appointing a loyal man as passenger agent When they had intended to let 'Mr. Prettyman transact the1icfuAe of their business in*this city. ,So the Gazette’s exposures have accomplished something.7. The Gazette has not “ coihe down but will accommodate the Herald and all• • • • aother rebel defenders of Mr. Prettyman, with an advertisement of their protege’s disloyalty just as often as they please to makeit necessary. . r