He breathed through the stalks of Van Baerle's tulips, quenched his thirst with the water he sprinkled upon them, and feasted on the fine soft earth which his neighbour scattered upon his cherished bulbs.
But the most curious part of the operations was not performed in the garden.
It might be one o'clock in the morning when Van Baerle went up to his laboratory, into the glazed cabinet whither Boxtel's telescope had such an easy access; and here, as soon as the lamp illuminated the walls and windows, Boxtel saw the inventive genius of his rival at work.
He beheld him sifting his seeds, and soaking them in liquids which were destined to modify or to deepen their colours.

He knew what Cornelius meant when heating certain grains, then moistening them, then combining them with others by a sort of grafting,--a minute and marvellously delicate manipulation,--and when he shut up in darkness those which were expected to furnish the black colour, exposed to the sun or to the lamp those which were to produce red, and placed between the endless reflections of two water-mirrors those intended for white, the pure representation of the limpid element.
This innocent magic, the fruit at the same time of child-like musings and of manly genius--this patient untiring labour, of which Boxtel knew himself to be incapable--made him, gnawed as he was with envy, centre all his life, all his thoughts, and all his hopes in his telescope.
For, strange to say, the love and interest of horticulture had not deadened in Isaac his fierce envy and thirst of revenge.

Sometimes, whilst covering Van Baerle with his telescope, he deluded himself into a belief that he was levelling a never-failing musket at him; and then he would seek with his finger for the trigger to fire the shot which was to have killed his neighbour.

But it is time that we should connect with this epoch of the operations of the one, and the espionage of the other, the visit which Cornelius de Witt came to pay to his native town..