At times, Petrus van der Velden pushed painting <em>en plein air</em> – in the open air – to the extreme. One of his former pupils, Leonard Booth, recalled the following encounter:
<em>When I was last at Otira, a resident of the place who remembered van der Velden told me that the Dutchman was evidently quite mad. Evidently? Yes, because at all those times when thunder rolled, and wind howled, and rain poured, van der Velden would go into the gorge, whereas at all those times when the sun shone from a cloudless sky, he would lie with his back to the grass near the hotel and sleep.</em>