A special class of labor songs were the so-called 'railroad songs,' which originated during the Civil War, when negroes were employed in building earth works and fortifications. They consisted of a series of rhythmic, protracted chants, upon words usually originated by a leader. Railroad tracks were laid to these same strains--hence their name. Their originality of thought and the fact that they represent the last spontaneous outburst of the negro under rapidly changing conditions, lends them a special interest. The railroad itself naturally stimulated the negro's imagination. He introduced it metaphorically even in his religious songs: the Christian was a traveller, the Lord was the conductor and the ministers were the brakemen. At gospel stations the train stopped for those that were saved, or to supply the engine with the water of life. All of the negro's power of imagery was here brought into play. The love songs of the negro are few and those few lack depth, and sometimes border on frivolity. An exception is usually made for 'Poor Rosy,' concerning which one old negress has said that 'it cannot be sung without a full heart and troubled spirit.' We have already pointed out the preponderance of religious songs in the folk-music of the negro. The reason is not hard to find. In his aboriginal home religious rite, music and dance were closely associated, as they are in the life of all primitive peoples. The African's religion was a form of idolatry known as voodooism. Connected with it were certain chants and rites, relics of which have long survived.[71] These primitive rites were calculated to excite the emotions rather than to uplift the spirit and under this excitement the negro gave voice to the music that was in him. He accepted the Christian religion as a substitute just as he accepted the English language as a substitute for his African tongue. He garbled both. He considered the new religion not in a dogmatic, philosophical, or ethical sense, but rather as an emotional experience. When under religious excitement he would wander through the woods in swamps much like the ancient Bacchantes. 'A race imbued with strong religious sentiment,' says Mr. M. A. Haskell,[72] 'one rarely finds among them an adult who has not gone through that emotional experience known as conversion, after which it is considered vanity and sinfulness to indulge in song other than of a sacred character.' His religion became the negro's one relief, comfort, and enjoyment. His daily life became tinged with his belief; in his very sufferings he saw the fulfillments of its promises. Nothing but patience for this life, nothing but triumph in the next--that was the tenor of his lay. Emancipation he thought of in terms of ultimate salvation rather than earthly freedom. Thus he sang: 'Children, we shall all be free, Children, we shall all be free, Children, we shall all be free, When the Lord shall appear.'