The fourteen miles of this second level are passed in one hour, and the train arrives at the foot of the second plane, which has seventeen hundred and sixty feet of length, and one hundred and thirty-two feet of perpendicular height. The third level has a length of a mile and five-eighths, a rise of fourteen feet six inches, and is passed by means of horses. The third plane has a length of fourteen hundred and eighty feet, and a perpendicular height of one hundred and thirty. The fourth level is two miles long, rises nineteen feet and is passed by means of horses. The fourth plane has a length of two thousand one hundred and ninety-six feet, and a perpendicular height of one hundred and eighty-eight. The fifth level is three miles long, rises twenty-six feet and is passed by means of horses. The fifth plane has a length of two thousand six hundred and twenty-nine feet, and a perpendicular height of two hundred and two, and brings you to the top of the mountain, two thousand three hundred and ninety-seven feet above the level of the ocean, thirteen hundred and ninety-nine feet above Hallidaysburg, and eleven hundred and seventy-two feet above Johnstown. At this elevation in the midst of summer, you breathe an air like that of spring, clear and cool. Three short hours have brought you from the torrid plain, to a refreshing and invigorating climate. The ascending apprehension has left you, but it is succeeded by the fear of the steep descent which lies before you; and as the car rolls along on this giddy height, the thought trembles in your mind, that it may slip over the head of the first descending plane, rush down the frightful steep, and be dashed into a thousand pieces at its foot. The length of the road on the summit of the mountain is one mile and five-eighths, and about the middle of it stands a spacious and handsome stone tavern. The eastern quarter of a mile, which is the highest part, is a dead level; in the other part, there is an ascent of nineteen feet. The descent on the eastern side of the mountain is much more fearful than the ascent on the western, for the planes are much longer and steeper, of which you are made aware by the increased thickness of the ropes; and you look _down_ instead of _up_. There are also five planes on the eastern side of the mountain, and five slightly descending levels, the last of which is nearly four miles long and leads to the basin at Hallidaysburg; this is travelled by the cars without steam or horse, merely by the force of gravity. In descending the mountain you meet several fine prospects and arrive at Hallidaysburg between twelve and one o'clock. _Letter XII_ is dated from Lancaster and is occupied with the return home of the adventurous Mr. Prolix, whose book we heartily recommend to all lovers of the _utile et dulce_. ARMSTRONG'S NOTICES. _Notices of the War of 1812. By John Armstrong. New York: George Dearborn._