assistance in discovering the murderer and bringing him to justice; while he is conversing with Donna Anna, Elvira again interposes and warns her that he is a hypocrite. He again secretly represents her as a maniac who must be humoured,[137] and goes out with her. Donna Anna's suspicions are aroused, and observing Don Giovanni closely, she recognises her father's murderer in him, acquaints Don Ottavio with the circumstances, and urges him to avenge her father's death. Unwilling to give easy credence to such a grave accusation, he decides to examine thoroughly into the affair, and to clear up the doubts as to Don Giovanni. The latter, disembarrassed of Donna Elvira, commands a banquet to be prepared in honour of the bridal party. Masetto, whom Zerlina has with difficulty appeased by her coaxing endearments, conceals himself when he sees Don Giovanni approaching; after some demure behaviour on Zerlina's part, Masetto comes forward, and Don Giovanni, with quick presence of mind, persuades them both to accompany him into the house for the banquet. Donna Anna and Don Ottavio enter with Elvira, who has explained everything to them, and at her instigation they all put on masks, in order to observe Don Giovanni without being recognised; Leporello, perceiving them, conveys the expected invitation to enter, which they accept. It was at that time customary in Venice to go about masked, and strangers thus disguised were invited to enter where any festivities were going on, thus heightening the frolic of the masquerade. As they enter the hall, there is a pause in the dance; the guests take refreshment, Don Giovanni devotes himself to Zerlina, and Masetto, his jealousy again aroused, seeks to warn her; then the masked strangers become the centre of observation, are politely greeted, and the dance begins again. Donna Anna and Don Ottavio tread a minuet, the dance of the aristocracy;[138] Donna Anna with difficulty restrains her conflicting emotions, which vent themselves in occasional interjections, while Don Ottavio exhorts her to remain calm. Elvira follows every movement of Don Giovanni; the latter invites Zerlina to dance, and Leporello forces Masetto to dance with him in order to distract his attention from Zerlina. At the right moment Don Giovanni carries off Zerlina. Leporello hurries after to warn him; her cries for help are heard, and all rush to her rescue. Don Giovanni meets them, dragging in Leporello, whom he gives out to be the culprit, and threatens with death; but he is surrounded on all sides, the masks are thrown off, and he finds himself in the midst of his victims,