History of saffron
fresco from the excavation of Akrotiri on the Aegean island of Santorini .
The history of saffron in human cultivation and use reaches back more than 3,000 years. and spans many cultures, continents, and civilizations. Saffron , a spice derived from the dried stigmas of t more
Atomic line filter Faraday filter designed, built and photographed by Jonas Hedin for making daytime LIDAR measurements at Arecibo Observatory.
An atomic line filter (ALF) is an advanced optical band-pass filter used in the physical science s for filtering electromagnetic radiation with precisi more
Chemical warfare
Chemical warfare involves using the toxic properties of chemical substance s to kill, injure or incapacitate an enemy .
Chemical warfare is different from the use of conventional weapon s or nuclear weapon s because the destructive effects of chemical weapons are not primarily du more
Acetic acid
Acetic acid, also known as ethanoic acid, is an organic chemical compound best recognized for giving vinegar its sour taste and pungent smell. Its structural formula is represented as CH3COOH. Pure, water -free acetic acid (glacial acetic acid) is a colourless liquid that attracts more
Slate industry in Wales
, Wales, about 1910.
The slate industry in Wales began during the Roman period when slate was used to roof the fort at Segontium , now Caernarfon . The slate industry grew slowly until the early 18th century, then expanded rapidly until the late 19th century, at which t more