The authorities arrested a number of Negroes but ran the risk of having the jail broken open by their sympathizing fellowmen.

After a reign of terror for half a week, order was restored and twenty of the accused were convicted of arson.
In 1820 there occurred so many conflagrations that a vigilance committee was organized.[16] Whether or not the Negroes were guilty of the crime is not known but numbers of them left either on account of the fear of punishment or because of the indignities to which they were subjected.
Numerous petitions, therefore, came before the legislature to stop the immigration of Negroes.

It was proposed in 1840 to tax all free Negroes to assist them in getting out of the State for colonization.[17] The citizens of Lehigh County asked the authorities in 1830 to expel all Negroes and persons of color found in the State.[18] Another petition prayed that they be deprived of the freedom of movement.

Bills embodying these ideas were frequently considered but they were never passed.
Stronger opposition than this, however, was manifested in the form of actual outbreaks on a large scale in Philadelphia.

The immediate cause of this first real clash was the abolition agitation in the city in 1834 following the exciting news of other such disturbances a few months prior to this date in several northern cities.