midnight
He then climbed into his sycamore . He had calculated correctly ; no one thought of keeping watch over the garden ; the house and the servants were all in the utmost confusion . He heard the clock strike -- ten , eleven , twelve . At midnight , with a beating heart , trembling hands , and a livid countenance , he descended from the tree , took a ladder , leaned it against the wall , mounted it to the last step but one , and listened . All was perfectly quiet , not a sound broke the silence of the night ; one solitary light , that of the housekeeper , was burning in the house . This silence and this darkness emboldened Boxtel ; he got astride the wall , stopped for an instant , and , after having ascertained that there was nothing to fear , he put his ladder from his own garden into that of Cornelius , and descended . Then , knowing to an inch where the bulbs which were to produce the black tulip were planted , he ran towards the spot , following , however , the gravelled walks in order not to be betrayed by his footprints , and , on arriving at the precise spot , he proceeded , with the eagerness of a tiger , to plunge his hand into the soft ground .