The passage discusses the historical use of tin in ancient Roman and British medicine, particularly in the form of stannic oxide (SnO₂). While tin was believed to have medicinal properties, modern research suggests that its primary function was as a pigment due to its non-toxic nature, which became increasingly recognized as a health hazard by the second century AD. The article also highlights a study on the water-repellent legs of water striders (Gerris remigis), which are covered with oriented tiny hairs (microsetae) with fine nanogrooves. These structures create a unique hierarchical surface that enhances water repellency, allowing the insects to stand and move on water surfaces efficiently. The study uses force-displacement curves and scanning electron microscopy to demonstrate that the legs' water repellency is due to a superhydrophobic effect, with a contact angle of 167.6 ± 4.4°. This discovery has potential applications in the design of miniature aquatic devices and non-wetting materials.The passage discusses the historical use of tin in ancient Roman and British medicine, particularly in the form of stannic oxide (SnO₂). While tin was believed to have medicinal properties, modern research suggests that its primary function was as a pigment due to its non-toxic nature, which became increasingly recognized as a health hazard by the second century AD. The article also highlights a study on the water-repellent legs of water striders (Gerris remigis), which are covered with oriented tiny hairs (microsetae) with fine nanogrooves. These structures create a unique hierarchical surface that enhances water repellency, allowing the insects to stand and move on water surfaces efficiently. The study uses force-displacement curves and scanning electron microscopy to demonstrate that the legs' water repellency is due to a superhydrophobic effect, with a contact angle of 167.6 ± 4.4°. This discovery has potential applications in the design of miniature aquatic devices and non-wetting materials.