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The cause'- of" the: accident' was as usual in such: casesnever ascertained,' for no one engaged-about the cartssurvived to tell "the story. Ample- reparation, however,was made by' the government to the; sulferers, who weremostly of the poorer classes,'as' on - that spot-the villasand habitations of the rich are removed some distancefrom the 1 high-road.-‘The'glaziers , however, had a good jobof it, as for miles' around not a window- was left entire.Some years 1 after this accident, • another of less fatalresults occurred at a depot of' sporting powder for thesupply ' of the public. On this' occasion I presented tothe inspector-general of artillery, a plan for the constructionof a powder -magazine, which, 'even' upon the explosionof the contents, would prevent the effects from - spreadinghorizontally far and wide as the one . last mentioned did.Although this is not exactly the place for its insertion,I will now give its description and so discharge my memoryof the fact.
In the year 1810, having witnessed the explosion' ofthis powder magazine near Naples, and examined the'effectsupon surrounding objects, I bethought me of constructingone upon a-principle that would obviate or confine asmuch as possible the danger consequent to ignition.
I communicated 'my plan to General Colletta, theninspector-general of artillery, who so highly approvedof it as -to; order one on a small scale to be constructedunder my inspection.
A circular pit was sunk twenty-five feet deep, and fortyin diameter. The bottom and sides, after being lined withstiff clay, were built up with the best puzzolana mortar, andstone or brick, and then coated with water-proof cement.The size of the cylindrical chamber when finished wastwenty feet deep, and as many in diameter. Being pro-tected from the rain, and allowed sufficient time to dry,