ceiling balloon
...that the height of clouds is measured using a ceiling balloon?
...that the height of <a href="./Cloud" id="mwBCw" rel="mw:WikiLink" title="Cloud">clouds</a> is measured using a <b id="mwBC0"><a href="./Ceiling_balloon" id="mwBC4" rel="mw:WikiLink" title="Ceiling balloon">ceiling balloon</a></b>?