1S4 Description of the Percussion Gun-Lock. 



The detonation is so powerful, that if a card be laid over the 

 pin, or even if its perforation be stopped with tallow, the gim 

 will, notwithstanding, be discharged. If the hammer is let down 

 gently after priming, the spring presses the pellet close into the 

 cavity, and thus considerably increases the effect. 



The paste is made of the several ingredients in the following 



proportions, viz. 



Graiiis. 



Oxymuriate of potash 190 



Flour of sulphur 68 



Fine powdered charcoal . . . . 34 



Gum arable 12 



Dissolve the gum in as little water as possible ; then grind the 

 oxynniriate of potash fine, in a Wedgwood's mortar, by itself, 

 and also the flour of sulphur and charcoal together, with a pestle 

 of the same material. The mixture of all with the gum must 

 then be effected, either in a wooden mortar with a wooden pestle, 

 or, at any rate, in a Wedgwood's mortar with a wooden pestle, 

 taking care to keep it moist during that operation, lest it should 

 explode. 



The paste, being of the consistence of soft clay, is then to be 

 formed into pellets, by means of a mould made of a plate of brass 

 or copper, one-sixteenth of an inch thick, and filled with holes 

 of one-eighth of an inch in diameter: this plate being placed 

 upon a table, or other flat surface, over which a sheet of paper is 

 first to be laid, the pa|Ste is to be spread evenly over its surface, 

 and then pressed into the holes, either by passing a roller over 

 it, or by beating upon it with a wooden mallet : the paste is then 

 to be removed from the upper face of the mould, with a thin 

 spatula or palette knife; and the mould is next to be slided, for 

 the length of an inch, along the paper, to separate the paste 

 from it ; and it may then be lifted up, and the pellets carefully 

 driven out of the holes in it, by striking u])on it with a soft 

 brush; they are then to be dried. The round paper patches 

 being cut by a proper punch are covered on one side with bees- 

 wax mixed with a little tallow, and coloured red to distinguish 

 the adhesive side from the other : the pellet is then gently pressed 

 on the t>entre of the waxed side of the patch, to which it adheres, 

 and the priming pa^ch is thus completed. 



When used, the patch is to be pressed firmly into the covniter- 

 sunk cavity of the head of the hammer, to wliich it easily ad- 

 heres in consequence of its waxed surface being in contact with 

 the metal. 



The following recipe for the composition of the pellets has 

 been communicated from another quaiter. 



Take 



