in the back of my mind ive heard of this type of firework before ," fireworks on strings hanging from trees" is a quote somewhere ...
so ill stick my neck out and say its designed to be hung and fired
Yes it rings a bell with me too, the description/measurements given ask many more questions, why was it tapered? was there a grove or ready made hole to attach some string? if so, how would the firework hang on the washing line or tree and was this crucial to its behaviour of flight etc etc?