MEMOIR OF DANIEL TEEADWELL. 483 



pruning powder. The explosion of the fiihninate expands the flange of the disk/ 

 against the sides of the recess b, and effectually closes the joint to the escape of 

 the gas. 



In the patent, dated November 25, 1862, the claim is as follows : " What I claim 

 is the efmployment in combination with the vent of a gun of a recess, or receptacle, 

 upon the exterior thereof, for containing a primer and a vent-stopper for closing the 

 same, and a primer with an expanding case, which serves as a packing to close the 

 joint and prevent the escape of the gas." 



A working model of the priming device is at the Observatory of Harvard College. 

 It has been frequently tested by enclosing in the instrument enough powder to half 

 fill its cavity, and fastening the button down firmly and firing. No report or noise is 

 at first heard, and neither fire nor smoke is seen. But in a few seconds there is a 

 slight blowing from the gas escaping or leaking by the side of the primer, and a smell 

 of sulphuretted h^-drogen. Sometimes most of the gas is held in the vent for hours, 

 so to speak, bottled up. 



A working model was placed in the hands of M. Souchard, Consul for France at 

 the city of Boston, to be forwarded as a present to the French Government. With the 

 model went also carefully written directions for its use. In a letter to M. Souchard, 

 Mr. Treadwell writes : — 



" On the supposition that the Emperor will deign to accept of my present, permit me to sug- 

 gest, in order that his examination of it may be made with the least labor to himself, that on 

 reaching its destination it be placed in the hands of some skilful ivorking enr/lneer, who shall 

 master the mode of operating and experimenting with it to demonstrate the ease and certainty 

 of its action, and that he be directed to exhibit it to His Majesty. 



" To facilitate the right understanding and working of everything connected with it by the 

 person to whom it shall be intrusted, I have drawn up for liis use a full description of the 

 machine, and the mode of charging and firing it, with a notice of all it is necessary to observe to 

 avoid any failure or accident. This description is enclosed with the instrument. I lament that 

 my imperfect knowledge of the French has obliged me, in writing it, to use my own language. 



" I have likewise taken the liberty to enclose in the case, in the hope that His Majesty 

 will accept it, a small volume comprising several memoirs relating to cannon that have been 

 published by me, and which give an account of some part of my long continued labors." 



The present was accompanied by the following dedication : " Appellatio ad 

 Cassarem. . . . Presented to His Imperial Majesty, Napoleon III., Emperor of the 

 French, with the most sincere and most profound respect and admiration. The 

 Author. Cambridge, December, 1862." 



The device was carefully examined by the Emperor personally, and a special com- 

 mission appointed by the Minister of War to examine and report upon its merits. A 



