This section is from the book "The Manual of Phonography", by Benn Pitman And Jerome B. Howard. Also available from Amazon: The Manual of Phonography.
The vowels 00 and ee, the two extreme members of the long-vowel scale, are, from the exceeding closeness of their formation in the mouth, of such a nature that any vowel may readily follow either of them and coalesce with it in the same syllable, forming a combination much like a diphthong. In such cases 00 and ee are formed even closer than usual, and so nearly approach true obstructed sounds that they are often considered as consonants and given consonantal representation by the strokes and
to which the vowel which follows may be written.
48. Coalescent Vowel-Signs. - It is convenient, however, to use vowel-signs for the coalescents in combination with the vowels, thus:

These signs are shaded to indicate the coalescence of oo and ee with the long vowels, but with short vowels they are light.
When w coalesces with V the resulting triphthong is written |
All these signs retain their own direction and do not vary with the stroke to which they are placed. Compare paragraphs 32 and 45.
Like the diphthongs (see par. 46) the first-place and third-place coalescent vowel-signs may be joined to the adjacent stroke, whenever they form a distinct angle.
When u is joined after n it may be slightly slanted as in renew, line 15.
a. When a word begins with w or y (1) the vowel-sign is used if it can be joined to the following consonant without lifting the pen (see lines I to 3), but (2) if this cannot be done the stroke form is written (see lines 4 to 7) except in cases where its joining with the following stroke is inconvenient, and then (3) the disjoined vowel-sign is used as in lines 8 to 10. b. When w or y occurs medially or in coalescence with a vowel at the end of a word the vowel-sign is generally preferred. See lines 11 to 15. c. When a word begins with a vowel followed by w or y the stroke must be used, as
awake.

 
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