To study insect flight, the scientists tied a cotton thread around a hawkmoth and placed it in a wind tunnel. They pumped nontoxic smoke through the tunnel and noted the way the smoke moved as the moth flapped its wings.
उन्होंने सुरंग में धुआँ पंप किया और जब पतंगे ने पंख फड़फड़ाए तो उस धुएँ के बहाव को नोट किया ।