Hudson and Mohaivk Rail Road. 141 



touching the tube, at any point above that where the finer portion 

 alone intervenes. To the outside of the tube a copper wire about 

 No. 16 is soldered, long enough to extend to a stout copper wire pro- 

 ceeding from one of the poles of a galvanic deflagrator or calorimo- 

 tor. The wire passing through the cork, from the inside of the tube, 

 is in like manner made to communicate with the other pole. The 

 connections between the wires, and the poles, should be made by 

 means of soft solder, previously to which we must imagine that the 

 tube has been introduced into a perforation made for its reception in 

 a rock to be blasted. The tin tube may be secured within the rock 

 by the usual method of ramming in brick dust or sand, by means of 

 a punch, having holes for the protection of the wires of communica- 

 tion already described. 



The apparatus being thus prepared, by a galvanic discharge, pro- 

 duced by the movement of a lever through a quarter part of a circle, 

 the finer wire is ignited, in the place where it intervenes solely in the 

 circuit, so as to set fire to the surrounding gunpowder. 



As the enclosure of the gunpowder in the tube must render it im- 

 possible that it should be affected by a spark elicited by ramming, as 

 no means of ignition can have access to the charge besides the gal- 

 vanic discharge ; and as this can only occur by design, without an 

 intention to commit murder or suicide, or unpardonable neglect, it is 

 inconceivable that an explosion can take place in this method of blast- 

 ing, when any person is so situated as to suffer by it. 



It must be obvious that in all cases of blasting under water, the plan 

 of the tin tube, and ignition by a galvanic circuit, must be very eligible. 



Mr. Shaw is now in Philadelphia, and I hope he may meet with 

 the patronage which his project merits. 



August, 1831. 



Art. XVIII. — Some account of the Hudson and Mohawk Rail Road^ 

 by S. DeWitt Bloodgood, Corresponding Secretary of the Al- 

 bany Institute. 



Without disparagement to similar works which have preceded 

 that of the Hudson and Mohawk Company, it may nevertheless be 

 considered as the most important, from its position, of any yet con- 

 structed in the United States. Albany, when in its infancy, was call- 

 ed by the appropriate title of "the net," since it caught all the travel, 



