DANGERS OF CHLORATE POWDERS. 



compositions. Potassium chlorate, which is the essential 

 ingredient, is a salt fusible at 334, and which decomposes 

 regularly at 352. Nevertheless, it may become explosive by 

 itself under the influence of a sudden heating, or a very violent 

 shock (p. 406). 



We have seen that it yields 39 '1 per cent, of oxygen and 

 60 4 9 of chloride of potassium 



C10 3 K = KC1 + 3 , 



liberating, at the ordinary temperature, 11 Cal. for each 

 equivalent of oxygen (8 grms.) fixed; or T4 Cal. per gramme 

 of oxygen ; or 0'54 CaL per gramme of potassium chlorate. 



These quantities of heat must therefore, generally speaking, 

 be added to those which would be produced by free oxygen, 

 when developing the same reaction at the expense of a com- 

 bustible body (p. 134). But the presence of the potassium 

 chloride, which acts as inert matter, tends to lessen this 

 advantage. 



3. The extreme facility with which potassium chlorate 

 powders explode under the influence of the least shock is a 

 consequence of the great quantity of heat liberated by the com- 

 bustion of the particles which are ignited at the very outset 

 and their low specific heat ; this heat raises the temperature of 

 the neighbouring portions higher in the case of chlorate than 

 of nitrate powder, and it therefore more easily propagates the 

 reaction. The influence is the more marked the lower the 

 specific heat of the compounds, 1 and as the reaction commences, 

 according to the known facts, at a lower temperature with the 

 chlorate than with the nitrate of potassium. 



Everything, therefore, combines to render the inflammation of 

 the powder with chlorate base easier. 



Therefore the substances of which they are formed should not 

 be pulverised or crushed together, but pulverised separately 

 and mixed by screening. 



The drying in the stove of these powders is dangerous. The 

 presence of powdered camphor, so efficacious with gun-cotton, 

 does not lessen the sensitiveness of chlorate powders. 



4. Not only is the chlorate powder more energetic and 

 inflammable, but its effects are more rapid; it is a shattering 

 powder. Theory again is able to account for the property. In 

 fact, the compounds formed by the combustion of chlorate 

 powder are all binary compounds, the simplest and most stable 

 of all, such as potassium chloride, carbonic oxide, and sulphurous 

 acid. Such compounds will undergo dissociation at a higher 

 temperature and in a less marked manner than the more com- 



1 In fact, these two powders only differ by the substitution of the chlorate, 

 the specific heat of which is 0-209, for the nitrate, the specific heat of which 

 is 0-239. 



