John Chalmers, in his "English and Cantonese pocket-dictionary" (1859) simplified the marking of tones using the acute accent to mark "rising" tones and the grave to mark "going" tones and no diacritic for "even" tones and marking upper register tones by italics (or underlining in handwritten work). "Entering" tones could be distinguished by their consonantal ending. Nicholas Belfeld Dennys used Chalmers romanization in his primer. This method of marking tones was adopted in the Yale romanization (with low register tones marked with an 'h'). A new romanization was developed in the first decade of the twentieth century which eliminated the diacritics on vowels by distinguishing vowel quality by spelling differences (e.g. a/aa, o/oh). Diacritics were used only for marking tones.