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prepared flate, it is (notwithftanding the low price) frequently. 

 adulterated with wheat-flour, which in moift or hot climates 

 readily induces fermentation, and irrecoverably decompofes the 

 powder: I am convinced that inattention to this circumftance 

 is a principal caufe of Britilh gun-powder being lefs durable now 

 than formerly. 



The moft eligible proportion of the three ingredients is next 

 to be confidered : and here I muft premifc, that after an accurate 

 examination of powder manufadured according to the moft 

 approved pradices in Europe and Afia, together with the 

 numerous variations of the chymifts, I find it beyond my ex- 

 perience to give a decided preference, as I have feen them all 

 fucceed and fail, changed by the qualities of the materials, or 

 influenced by the temperature of the atmofphere, either when 

 the powder was manufadured and barrelled, or when it was 

 proved. I would therefore recommend that the. proprietors of 

 powder-mills fliould manufadure a fmall quantity of powder 

 from each frefli aflTortment of materials. In doing this the fol- 

 lowing canon, which is borrowed from the Frerich pyrotcchnifts, 

 and eftablifhed by experiments, may be found ufeful : begin with 

 3 lbs. of nitre and 90Z. of charcoal, (this will explode without 

 fulphur,) increafe the quantum of charcoal till the moft forcible 

 combination of thofe two ingredients is difcovered, which will 

 commonly happen at between 120Z. and ilb. of charcoal to the 

 3lbs. of nitre; to this procefs let fulphur be added, beginning 

 with :5 0z. till the ftrongeft explofion is found, which will be 

 when the proportion of this ingredient to the above is from 

 2f to 3+02. Finally, let the dofe of charcoal. he d'lminidicd, till 



the 



