928 Transactions of the American Institute. 



transportation of mail matter, but the scarcely leas gigantic one of 

 sub-tnbing the North and East rivers and thus uniting Jersey city 

 and Brooklyn with New York. 



It is estimated that the actual expense of laying down pneumatic 

 passenger tubes under the streets of the city in the best manner with 

 iron tubing, including the runnitig stock and engines, would not 

 exceed $100 per running foot, or $500,000 per mile, being much 

 below the estimated cost of an underground steam car railroad. The 

 pneumatic plan would, doubtless, require a smaller tube than any 

 other form, and, consequently, less excavation would be required, 

 and since, by actual experience, it is shown that it can describe the 

 sharpest curve, the route would not be difficult of selection. The 

 suspension of the tube at the tair illustrates the practicability of an 

 elevated road, and suggests that the tube might be readily placed'on 

 posts or on brackets projecting from the houses passing between*the 

 blocks, or even running over the house-tops. 



The estimated cost of laying down the pneumatic passenger rail- 

 road tube under the East river is $200 per running foot. Estimating 

 the distance at 3,000 feet, this would give an outlay of 't$600,000. 

 Assuming this to be correct, the contrast between this sum and the 

 $7,000,000 which the great suspension bridge is to cost, the differ- 

 ence is startling. For the larger snm it is claimed that a dozen or 

 more pneumatic tubes could be laid down, aflbrding ample trans-river 

 accommodation at every important point on either river, connecting 

 aJl the great leading thoroughfares of the sister cities. 



It is further estimated that prtssengera by a through city tube 

 could be carried from the City Hall to Madison square in five 

 minutes, to Central Park in eight minutes, to Harlem and Manhat- 

 tanville in fourteen minutes, to Washington Heights in twenty 

 minutes, and by sub-river to Jersey city or Iloboken in .five minutes 

 and. to the city hall, Brooklyn, in two minutes. And that this, if 

 ever accomplished, whicli is by no means improbable, ought to be 

 done at rates of conveyance far below those now charged for most 

 uncomfortable transportation, it is only fair to conclude from the 

 comparatively limited outlay of construction anticipated. 



The projected pneumatic postal dispatch is of a very important 

 and( comprehensive character. It is proposed to carry a pneumatic 

 tube of about two or three feet m diameter from the post-office up 

 Broadway to Forty-second street, with branches at Twenty -seventh 

 street to the Harlem and New Haven railroads, and a branch at 



