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Salvinia Effect of Salvinia natans

Scanning electron micrograph of leaf detail of Salvinia natans, a floating fern type plant which has superhydrophobic trichomes or hairs on the upper surface of its leaves. Each of these eggbeater shaped hairs exhibits a hydrophilic tip on the top of each hydrophobic hair. The combination of a hydrophobic surface with hydrophilic tips is called the "Salvinia Effect". These air retaining surfaces are of great interest, particularly with regards to fuel consumption when applied to ships having to overcome friction produced by the drag of water on their hulls. This drag could be reduced dramatically with the "Salvinia Effect", a layer of air between the ship's hull and the water, saving vast amounts of fuel. A suggested estimated saving of 20 million tons of oil per year for just a 10% decrease in drag for shipping alone. Magnification: x372 (x122 at 10cm wide)

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Cave of Crystals, Naica Mine, Mexico

^BCave of Crystals.^b Geologist standing in the Cave of Crystals (^ICueva de los Cristales^i) in Naica Mine, Chihuahua, Mexico. The crystals are the largest known in the world, and are formed of the selenite form of gypsum (calcium sulphate). They formed over millions of years in the mineral-rich geothermally heated water that filled the caves. The crystals were discovered after the water was pumped out of the mine. The Cave of Crystals is 290 metres deep, and was discovered in 2000. Above it, 120 metres deep, is the Cave of Swords (^ICueva^i ^Ide^i ^Ilas Espadas^i), which was discovered in 1912. The crystals in this cave are smaller as its water cooled more rapidly

© JAVIER TRUEBA/MSF/SCIENCE PHOTO LIBRARY

The Sceptical Chymist (1661)

The Sceptical Chymist (1661). This title page is from the first edition of this work by the Anglo-Irish natural philosopher Robert Boyle (1627-1691). In this book, written in the form of a discourse (dialogue), Boyle wrote that elements combine to form compounds, which can be broken apart again into their constituent elements. He also argued for chemistry to become an experimental science in its own right, speaking out against the influence of alchemists and spagyrists (alchemists who used herbal medicines). This work is considered a founding text of modern chemistry. It was first published in English, and later translated into Latin

© GREGORY TOBIAS/CHEMICAL HERITAGE FOUNDATION/SCIENCE PHOTO LIBRARY