to sparkle with unusual fire and vivacity

Understanding that her grandmother had left her a sum of money independent of her parents, he conveyed a letter to her mother, intimating, that her daughter, on pretence of going to the masquerade, intended to bestow herself in marriage to a certain person, and that in a few days she would be informed of the circumstances of the whole intrigue, provided she would keep this information secret, and contrive some excuse for detaining the young lady at home, without giving her cause to believe she was apprised of her intention. This billet, subscribed “Your well-wisher, and unknown humble servant,” had the desired effect upon the careful matron, who, on the ball day, feigned herself so extremely ill, that Miss could not with any decency quit her mamma’s apartment; and therefore sent her apology to Emilia in the afternoon, immediately after the arrival of Peregrine, who pretended to be very much afflicted with the disappointment, while his heart throbbed with a transport of joy.
About ten o’clock the lovers set out for the Haymarket, he being dressed in the habit of Pantaloon, and she in that of Columbine; and they had scarce entered the house when the music struck up, the curtain was withdrawn, and the whole scene displayed at once, to the admiration of Emilia, whose expectation was infinitely surpassed by this exhibition. Our gallant having conducted her through all the different apartments, and described the economy of the place, led her into the circle, and, in their turn, they danced several minuets; then going to the sideboard, he prevailed upon her to eat some sweetmeats and drink a glass of champagne. After a second review of the company, they engaged in country dances, at which exercise they continued until our adventurer concluded that his partner’s blood was sufficiently warm for the prosecution of his design. On this supposition, which was built upon her declaring that she was thirsty and fatigued, he persuaded her to take a little refreshment and repose; and, for that purpose, handed her downstairs into the eating-room, where, having seated her on the floor, he presented her with a glass of wine and water; and, as she complained of being faint, enriched the draught with some drops of a certain elixir, which he recommended as a most excellent restorative, though it was no other than a stimulating tincture, which he had treacherously provided for the occasion. Having swallowed this potion, by which her spirits were manifestly exhilarated, she ate a slice of ham, with the wing of a cold pullet, and concluded the meal with a glass of burgundy, which she drank at the earnest entreaty of her admirer. These extraordinary cordials co-operating with the ferment of her blood, which was heated by violent motion, could not fail to affect the constitution of a delicate young creature, who was naturally sprightly and volatile. Her eyes began to sparkle with unusual fire and vivacity, a thousand brilliant sallies of wit escaped her, and every mask that accosted her underwent some smarting repartee.