922 Transactions of the American Institute. 



wliich impeded the healthy working of the project ; but it was not 

 until in 1861 a company was formed in London, entitled the Pneumatic 

 Dispatch Company, and that they laid their plans before the public, 

 that conlidence in the ultimate realization of a successful atmospheric 

 railroad was established. There was nothing new in principle claimed 

 by the invention in the hands of the new company, but its application 

 was materially difterent ; and to this, and to modifications of this im- 

 provement, are due not only the success which has attended the labors 

 of six years, but, beyond a doubt, the great revolution in locomotion 

 which is still before us. The first experiment with the new apparatus 

 was made in Battersea Fields, on the south side of the Thames, in 

 the southwest suburbs. An iron tube over a quarter of a mile long 

 was laid along the river's bank, and mail bags, parcels, and even 

 several of the workmen, were carried through it at a rapid rate. As 

 before stated, the principle by which this was effected was the same 

 as that upon which the former roads were constructed ; the great and 

 important difi'erences lay in the application. The car was no longer 

 drawn over i-ails laid alongside a tube, but with its load passed through 

 one of sufficient diameter to admit it as a piston. There was still 

 the tube and the exhausting apparatus, but self-sealing valves were 

 no longer necessary. The tube was not circular in form, but of a 

 section resembling that of an ordinary railwa}' tunnel, the internal 

 height two feet nine inches, and the width at the spring of the arch 

 two feet six, and at the springing of the invert two feet four inches. 

 The material of the tube was of cast iron, in nine feet lengths, each 

 weighing about a ton, and fitted into each other with an ordinary socket 

 joint properly packed. Within the tube and at the lower angles on either 

 side were cast raised ledges, two inches wide on the top and one inch 

 high, answering the purpose of rails for the wheels of the dispatch 

 truck to run upon. The trucks were made of a framing seven or 

 eight feet long, inclosed in sheet iron, and having four flanged 

 wheels, twenty inches in diameter each. The truck was so formed 

 that its external form, in cross section, conformed to the inner sur- 

 face of the tube, although not fitting closely, as this was found to be 

 no neeessity of successful operation, and freedom from friction, 

 beyond that of the wheels, was thus obtained. The air was exhausted 

 from near one end of the tube, by means of a great exhausting fan 

 from which the air obtained by the suction was discharged by centri- 

 fugal force. 



These first experiments, which were made in July of 1861, as 



