Rainforests, earthquakes and liquid glass...

We explore archaeologists' revelation that people have been riding on, eating and drinking the milk of horses for over 5,000 years; why the Amazon forest might become a carbon criminal; how marine organisms produce laughing gas; how a mutated gene has been linked to pancreatic cancer; how observations from space provide information on how the ground recovers after an earthquake. Plus in 'Stuff and Non-Science', are old glass windows thicker at the bottom because glass is a liquid?