Read it through once

Tom and Huck, transported by this success, deemed it their duty to mount guard upon the quays. They sat through a night chill and uncomfortable, but their vigil was rewarded; at dawn they perceived a glimmer of light on the water and the silhouette of a vessel loosing her tackles. The boys, with childish craft, managed to get aboard the steamer, hid in a hay-bale, and thus became silent spectators of a scene which soon put them in the center of a real adventure.