Benoît de Cornulier's writings on French poetry concentrate on metrical boundaries, or caesura; however, the the criteria upon which he bases his analyses are useful in studying rhythm, or the relationship between syllables within the alexandrine's twohémistiches. This study focuses on three aspects of rhythm in French poetry: the definition of rhythm following Cornulier; the development of a method using the computer to detect rhythmic patterns in traditional isometrical alexandrines; the results of such a study when applied to three classical seventeenth-century plays which are composed of isometrical alexandrines (Corneille'sPolyeucte, Racine'sPhèdre, and Molière'sLe Tartuffe).