visibly destructive for periods of 2 minutes 2 1 2 silica acid mixture add 12 82 g of 200 m 2 g fumed silica to 500 g of 66 u00b0 baume sulfuric acid the mixture thickens just short of being a gel and has a viscosity reading of 1850 cps on the viscometer one ml of the mixture on a paper towel requires 2 minutes to burn through when 143 59 g of the mixture is added to 150 ml of water at 20 u00b0 c the temperature rises to 70 u00b0 c the effect of the 2 1 2 mixture on cotton wool and parchment is not visibly destructive for periods of 3 minutes the proportions of sulfuric acid and fumed silica according to the present invention are variable within certain limits compositions containing less than 1 0 by weight fumed silica do not thicken enough to achieve the objects of the present invention compositions containing 3 0 by weight or more fumed silica form a gel or grease like composition which cannot be poured and which must be handled like a grease compositions containing a significantly higher percentage 10 by weight or more of fumed silica form dry granular mixtures compositions containing between 1 0 to 2 9 fumed silica and more particularly 2 5 fumed silica form a thick pourable product which achieves the objects of the present invention the heat of release generated by the exothermic reaction at the sulfuric acid is the same for the varying compositions of sulfuric acid and fumed silica that is to say the presence of the fumed silica does not impede the rapid generation of heat.