In the words _a red house_, each word preserves its natural and original meaning, and the statement suggested by the term is _that a house is red_. By a parity of reasoning _a mad house_ should mean a _house that is mad_; and provided that each word retain its _natural meaning_ and its _natural accent_, such is the fact. Let a _house_ mean, as it often does, a _family_. Then the phrase, _a mad house_, means that the _house_, _or family_, _is mad_, just as a _red house_ means that the _house is red_. Such, however, is not the current meaning of the word. Every one knows that _a mad house_ means _a house for mad men_; in which case it is treated as a compound word, and has a marked accent on the first syllable, just as _Límehouse_ has. Now, compared with the word _red house_, meaning a house of a _red colour_, and compared with the words _mad house_, meaning a _deranged family_, the word _mádhouse_, in its common sense, expressed a compound idea; as opposed to two ideas, or a double idea. The word _beef steak_ is evidently a compound idea; but as there is no disparity of accent, it is not a compound word. Its sense is compound. Its form is not compound but double. This indicates the objection anticipated, which is this: viz., that a definition, which would exclude such a word as _beef steak_ from the list of compounds, is, for that very reason, exceptionable. I answer to this, that the term in question is a compound idea, and not a compound form; in other words, that it is a compound in logic, but not a compound in etymology. Now etymology, taking cognisance of forms only, has nothing to do with ideas, except so far as they influence forms. Such is the commentary upon the words, _treating the combination as a single term_; in other words, such the difference between a compound word and two words. The rule, being repeated, stands (subject to exceptions indicated above) thus:--_there is no true composition without either a change of form or a change of accent_. § 360. As I wish to be clear upon this point, I shall illustrate the statement by its application. The term _trée-rose_ is often pronounced _trée róse_; that is, with the accent at _par_. It is compound in the one case; it is a pair of words in the other. The terms _mountain ash_ and _mountain height_ are generally (perhaps always) pronounced with an equal accent on the syllables _mount-_ and _ash_, _mount-_ and _height_, respectively. In this case the word _mountain_ must be dealt with as an adjective, and the words considered as two. The word _moúntain wave_ is often pronounced with a visible diminution of accent on the last syllable. In this case there is a disparity of accent, and the word is compound. § 361. The following quotation indicates a further cause of perplexity in determining between compound words and two words:-- 1.