Their romanization system embodied the phonological system in a local dialect rhyme dictionary, the "Fenyun cuoyao", which was widely used and easily available at the time and is still available today. Samuel Wells Willams' "Tonic Dictionary of the Chinese Language in the Canton Dialect" ("Yinghua fenyun cuoyao" 1856), is an alphabetic rearrangement, translation and annotation of the "Fenyun". To adapt the system to the needs of users at a time when there were only local variants and no standard—although the speech of the western suburbs, "Xiguan", of Guangzhou was the prestige variety at the time—Williams suggested that users learn and follow their teacher's pronunciation of his chart of Cantonese syllables. It was apparently Bridgman's innovation to mark the tones with an open circle (upper register tones) or an underlined open circle (lower register tones) at the four corners of the romanized word in analogy with the traditional Chinese system of marking the tone of a character with a circle (lower left for "even," upper left for "rising," upper right for "going," and lower right for "entering" tones).