Sentence:  In <WSD>trumpets</WSD> for assisting the hearing, all reverbation of the <WSD>trumpet</WSD> must be avoided. It must be made thick, of the least elastic materials, and covered with cloth externally. For all reverbation lasts for a short time, and produces new sounds which mix with those which are coming in. 
Meaning of the word marked with <WSD> tags:  A musical instrument of the brass family, generally tuned to the key of B-flat; by extension, any type of lip-vibrated aerophone, most often valveless and not chromatic.