EXCURSIONS.--Remember the excursions in behalf of Mitchell, the Irish patriot, to-morrow. The advertisement will be found in our columns. The excusion (sic) is up the Hudson to Rockland Lake.
There is also an excursion to Coney Island. Another on the Long Island Rail Road and some others beside advertised to-day to which we refer those who wish to go out of the city.
--Brooklyn Daily Eagle, Monday, July 3, 1848
Sadly, the Coney Island ad for 4th of July is basically illegible, having been marked through on the website. But I'm sure people visited and had a lovely time.
What's the deal with Mitchell? From other articles, it appears they're referring to John Mitchel, Irish nationalist (some info at http://adbonline.anu.edu.au/biogs/A020204b.htm).
This site notes he was convicted of treason in Ireland in May 1848 and sentenced to 14 years "transportation" in what is now Tasmania. Eventually he escaped to America, and did a lot of writing. He supported Southern slaveholders!
June 21, 1848, there was a meeting in his support.
The great Irish meeting on Fort Green.
The storm of yesterday cleared up just in time to permit the Irish meeting to be held at, or at a little after the appointed hour, but the grass was wet and vast numbers, especially of the woman, who had arranged to attend were thus prevented. Still there was a very large assemblage--we should say about five thousand persons--who braved the threatening clouds and the dripping grass and met on this old camping ground to speak in behalf of poor Ireland, and the brave and gallant woman who has sacrificed her patriotic husband in the cause of her country....
--Brooklyn Daily Eagle, Wednesday, July 21, 1848
An article from Tuesday, June 27, 1848 notes that "Mr. Wm. Mitchell", John's brother, was at the Astor house. In an article from Thursday, June 29, 1848, Brooklyn's mayor dispersed a gathering of Irish who had supposedly gathered to "meet and pray for the deliverance of Mitchell from his convict ship at Bermuda", apparently for "breaking the Sabbath". (The Eagle, however, claims "the mayor only advised that the meeting should quietly disperse.")
I find the inconsistency in spelling names (Mitchell or Mitchel) to be really interesting. I know Irish names were modified for America, but "Mitchel" doesn't seem like it needed changed to me...