CHAPTER XXXVII. 



Cincinnati to Pittsburg. Improved Machinery of Steamer. Indian Mound. 

 Gravel Terraces. Pittsburg Fire. Journey to Greensburg. Scenery 

 like England. Oregon War Question. Fossil Foot-prints of Air-breath 

 ing Reptile in Coal Strata. Casts of Mud-cracks. Foot-prints of Birds 

 and Dogs sculptured by Indians. Theories respecting the Geological 

 Antiquity of highly organized Vertebrata. Prejudices opposed to the 

 Reception of Geological Truths. Popular Education the only Means of 

 pi-eventing a Collision of Opinion between the Multitude and the Learned. 



April 13, 1846. FROM Cincinnati we embarked in the Clip 

 per steamer for Pittsburg, a distance of no less than 450 miles ; 

 so magnificent is the scale of the navigation of this mere tribu 

 tary of the Mississippi ! Yet there are other large steamers also 

 plying above Pittsburg, on the tributaries of the Ohio. We ob 

 serve more punctuality than in 1842, in the starting of the steam 

 ers. The Clipper made ten miles an hour against the current, 

 including stoppages. We fell in with some large artificial rails 

 of wood stretching more than half across the river, and met a 

 steamer, which had run foul of one of them, still entangled, and, 

 though bound for Pittsburg, floating down the stream with the 

 raft. Our steamer only draws 3^ feet water, and her engines 

 are of a very peculiar construction, hitherto used in sea-boats only, 

 with the exception of one on Lake Erie. The inventor of this 

 improvement is Thomas K. Litch. There are two cylinders, one 

 twice the size of the other, and the steam escapes from the smaller 

 into the larger, instead of issuing into the open air, so that its 

 heat is not lost. The economy of fuel arising from this contriv 

 ance is great, and the vibrations and noise much less than in 

 other boats on the same high-pressure principle. In place of the 

 usual bell, signals are made by a wild and harsh scream, pro 

 duced by the escape of steam, as in locomotive engines ; a fear 

 ful sound in the night, and which, it is to be hoped, some ma 

 chinist who has an ear for music will find means to modulate. 



