<?xml version="1.0" encoding="utf-8"?><!DOCTYPE Zthes SYSTEM "http://zthes.z3950.org/xml/zthes-05.dtd">  <Zthes><term><termId>31381375</termId><termName>sound mirrors</termName><termType>PT</termType><termNote><![CDATA[ Concrete structures of various forms, usually including a concrete dish linked to microphones, acting as early warning systems to detect and transmit the sound of incoming zeppelins; installed along the English coast facing Europe during the early 20th century. ]]></termNote><termCreatedDate>2026-03-30 20:42:54</termCreatedDate><relation><relationType>UF</relationType><termId>31381376</termId><termName>acoustical sound mirrors</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31381377</termId><termName>listening posts</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31381378</termId><termName>mirrors, sound</termName><termType>ND</termType></relation><relation><relationType>UF</relationType><termId>31381379</termId><termName>sound mirror</termName><termType>ND</termType></relation><relation><relationType>BT</relationType><termId>31350844</termId><termName>communications structures</termName><termType>PT</termType></relation></term>  </Zthes>