Сирин или сирена

Sirin or siren. About the sweetness of the singing of this bird (page 85, p. 407). This index is based on the index appended to the works of St. Isaac the Syrian, published by Optina Pustyn in 1854. * “Ascetic words.” Reprint. Sergiev Posad. 1911. M.: “Rule of Faith”, 1998