* * * * *

SPIRIT OF DISCOVERY.

BIRMINGHAM RAILWAY.

The line of the proposed plan for this useful and excellent undertaking has been forwarded to us.  We know not whether the projectors are aware that a straight line is no longer necessary, but that the sharpest turns may now be made on rail-roads by an American invention, lately carried into effect in the United States with singular success.—­The line of railway will be 112-1/2 miles.  Birmingham being between 3 and 400 feet higher than London, and the intervening ground much broken, the railway could not be laid down without an inclination in its planes; the rise, however, will in no case exceed 1 in 330.  The highest point of the line is on the summit of an inclined plane 15 miles long, rising 13-1/3 feet in each mile, and is 315 feet above the level at Maiden Lane, London; from which it is distant 31 miles.  The termination at Birmingham is 256 feet higher than the commencement at London.  It is intended that there should be 10 tunnels—­one at Primrose Hill half a mile long, one near Watford a mile long, and one near Kilsby, 78 miles from London, a mile and a quarter long.  The others are each less than a quarter of a mile in length, with the exception of one, which is a third of a mile long.  They will all be 25 feet in height, well lighted, and ought rather to be called galleries than tunnels.  The strata through which the railway is carried, appear generally to follow in this order from London: 

Miles. 
London clay and plastic clay 15-1/2
Chalk and chalk flints 18-1/2
Chalk, marl, weald clay, iron sand,
and Oxford clay or clunch clay 20
Great and inferior oolite limestones,
and sandy beds 18
Lias marls, lias limestone or water
lime and shale beds 16
Red marl and new red sandstone 24-1/2
-------
112-1/2

The railway will be composed of two lines of rails with a space between them of six feet, but at particular points two additional lines will be required as turns-out to facilitate the passage of the locomotive engines and carriages.  If we assume the average rate of travelling on the railway to be 20 miles an hour, (which is about the mark,) that 1,200 persons pass along it in a day, and 120 are conveyed in each train of carriages, then only ten trains of carriages would be required for all the passengers; each train would separately take a minute and a half, and the ten trains not more than fifteen minutes in passing over half a mile of ground.  Allow twice this time for the passage of cattle and merchandise, and it is manifest that the traffic on railways can never be a source of annoyance to persons residing near them.  All who have travelled in carriages drawn by locomotive steam-engines on the Liverpool and Manchester railway can vouch for the safety and comfort, as well as the