“Though wonder is doubtless the energy that pulses through the brush of every committed painter, in truth, only a rare few have managed successfully to capture its essence as a palpable property in their work. The recent rediscovery in 2019 of a work by the British Enlightenment artist Joseph Wright of Derby that was hitherto unknown to art historians, was itself a cause for awe, nicely echoing the very subject of the painting: two boys testing the volume of a luminous bladder, lit up by the flicker of an unseen flame guttering behind it.”
Lungs are like a sponge inside (maximum surface area) so more dense than an empty bladder, not as much light would go through. We (the English) used these bladders as the first rugby and footballs in the 1800’s.