内容摘要：Trump said Musk's welcome at the White House was wearing thin and accused him of being unhappy about the elimination of a tax credit for electric vehicles, which has been key to Tesla's sales in the US.

Trump said Musk's welcome at the White House was wearing thin and accused him of being unhappy about the elimination of a tax credit for electric vehicles, which has been key to Tesla's sales in the US.

"It shines light on the book and measures the amount of light which shines back," he says."It uses green light, which can be seen, and infrared, which can't be seen with our own eyes. The green light flashes when there are no fragments of arsenic present, the red light when there are pigments."

The new testing device is smaller and will be less costly to produce and use than a full-scale spectrometerIt has already been used to survey the thousands of books in the St Andrews collections and in the National Library of Scotland, and the team hope to share their design with other institutions around the world."We're lucky as a large institution to have expensive kit, so that we can test 19th Century potentially toxic books," says Dr Jessica Burge, deputy director of library and museums at the University of St Andrews.

"But other institutions with big collections may not have those resources, so we wanted to create something which was affordable and easy. It doesn't require a specialist conservator or analysis, and it's instant."It's also a problem which isn't going away. If anything, toxic books will become more harmful as they get older and disintegrate.

Identifying them means they can stored in a safe way and still enjoyed with controlled access and precautions such as wearing gloves.

"It will continue to be a live issue," says Dr Burge.Neither side has succeeded so far. For decades, successive Indian governments - both at the Centre and in Kerala - have tried and failed to resolve the deadlock.

It remains unclear if Saudi authorities are even willing to release the compensation, let alone adjust it for inflation as some family members now demand - with some claiming it could be worth over $1bn today.Followers of the case note the property was a waqf - an Islamic charitable endowment - meaning descendants can manage but not own it.

The Saudi department that handles Awqaf (endowed properties) did not respond to the BBC's request for comment, and the government has made no public statement on the matter.That hasn't stopped speculation - about both the money and who it rightfully belongs to.