- on the surface or the outside
- 1820, Encyclopaedia Britannica; Or A Dictionary of Arts, Sciences, and Miscellaneous Literature, volume 20, 6th edition, Edinburgh: Archibald Constable and Company, page 501:
- In trumpets for assisting the hearing, all reverbation of the trumpet 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.