All the so-called aspirates are continuous; and, with the exception of _s_ and _z_, all the lenes are explosive. I believe that in the fact of each mute appearing in a fourfold form (_i.e._ sharp, or flat, lene, or (so-called) aspirate), lies the essential character of the mutes as opposed to the liquids. _Y_ and _w_.--These sounds, respectively intermediate to _[gamma]_ and _i_ (the _ee_ in _feet_), and to _[upsilon]_ and _u_ (_oo_ in _book_), form a transition from the vowels to the consonants. s. 204. It has been seen that the sixteen mutes are reducible to four series. Of these series, _p_, _t_, _k_, _s_, may respectively be taken as the types. Of the liquids it may be predicated as follows:-- 1. That _m_ is allied to the series _p_.--The combination _inp_ has a tendency to become _imp_. 2. That _n_ is allied to the series _t_.--The combination _imt_ has a tendency to become either _impt_, or _int_. 3. That _l_ is allied to the series _k_.--The evidence of this lies deep in comparative philology. 4. That _r_ is allied to the series _s_.--The evidence of this is of the same nature with that of the preceding assertion. The series _p_ and _k_ have this peculiarity.--They are connected with the vowels through _w_ and _u_ (_oo_), and through _y_ and _i_ (_ee_) respectively. s. 205. The French word _roi_ and the English words _oil_, {148} _house_, are specimens of a fresh class of articulations; _viz._, of compound vowel sounds or _diphthongs_. The diphthong _oi_ is the vowel _o_ modified, plus the _semi_vowel _y_ (not the _vowel_ _i_) modified. The diphthongal sound in _roi_ is the vowel _o_ modified, _plus_ the semivowel _w_ (not the vowel _u_ or _oo_) modified. In _roi_ the semivowel element precedes, in _oil_ it follows. In _roi_ it is the semivowel allied to series _p_; in _oil_ it is the semivowel allied to series _k_. _The nature of the modification that the component parts of a diphthong undergo has yet to be determined_; although it is certain there is one. If it were not so, the articulations would be _double_, not _compound_. The words quoted indicate the nature of the diphthongal system. 1. Diphthongs with the semivowel _w_, _a_) _preceding_, as in the French word _roi_, _b_) _following_, as in the English word _new_. 2. Diphthongs with the semivowel _y_, _a_) _preceding_, as is common in the languages of the Lithuanic and Slavonic stocks, _b_) _following_, as in the word _oil_. 3. Triphthongs with a semivowel both _preceding_ and _following_. The diphthongs in English are four; _ow_ as in _house_, _ew_ as in _new_, _oi_ as in _oil_, _i_ as in _bite_, _fight_. s. 206. _Chest_, _jest_.--Here we have compound consonantal sounds. The _ch_ in _chest_ is _t_ + _sh_ ([sigma]), the _j_ in _jest_ is _d_ + _zh_ ([zeta]). I believe that in these combinations one or both the elements, _viz._, _t_ and _sh_, _d_ and _zh_, are modified; but I am unable to state the exact nature of this modification.