M 



Two other ad- 

 vantages in 

 this. 



The author's 

 theory. 



Lead easily 

 reduced. 



Its aeetate con- 

 verts rope into 

 a match. 



Light woods 

 absorb most 

 salt. 



MATCHES FOR ARTILLERY. 



might yield flame, without detriment to the action of thi 

 nitrate; and my hopes were realised, for rods thus pre- 

 pared furnished both light and fire at pleasure. In this 

 addition I found two other advantages : one, that of render- 

 ing the wooden match impervious to water; the other, that 

 of facilitating the reduction of the lead, part of which I 

 was apprehensive might be carried oiF in vapour, and in- 

 jure the health of those who respired it. 



The theory of the process I adopted is simple ; and it is 

 easy to explain, why metallic nitrates succeed better than 

 nitrate of potash. However dry the wood may be, it al- 

 ways retains a little of its water of vegetation or of com- 

 position, which is an obstacle to its proper combustion. 

 By boiling the rods in a solution of nitrate of lead or of 

 copper, which on account of its specific gravity requires a 

 high temperature; this fluid dilates, softens, and penetrates 

 the fibres of the wood, and expels their water of vegeta- 

 tion, which is replaced by that of crystallization. The 

 nitrate then comes into immediate contact with the carbon 

 of the wood, whence the rapidity of its combustion. 

 The nitrate of potash does not answer so well, because, re- 

 taining much water of crystallization, its solution does not 

 acquire so high a temperature : and, supposing it able to 

 penetrate the wood as intimately, it carries into it too 

 much water, for its combustion to be progressive and con- 

 tinual, A proof of this reasoning may be found in the 

 composition of the two salts : nitrate of lead contains -75 

 of its base, that of potash but -49. 



The rapid combustion of the wooden match is owing 

 also to the facility, with which the salts of lead arc re- 

 duced, when in contact with burning charcoal. If a 

 hempen rope be boiled in a solution of acetate of lead, and 

 afterward dried, it may be used as a match. It burns 

 slowly like touchwood, and has a very bright coal. The 

 oxide of lead, as the metal is reduced, gives out its oxigen 

 to the carbon, and accelerates the combustion*. 



On comparing the specific gravity of wood with its satu- 



* We have a familiar instance of this in the popular experiment 

 of burning a red wafer in the flame of a candle. Ed. 



ratio* 



