Tons or Tonnes?

just a quick question why you used tonnes instead of just tons in you description of the "installation of the Great Chain—65 tonnes of iron stretched across 600 yards of river from West Point to Constitution Island", but used YARDS...just asking??...................................Hi Sharon...Thank you for your message. Fantastic observation! I wish I had a really intelligent response for you but…. I made a mistake. It should have been 65 ‘tons' and I wrote ‘tonnes'. It’s a funny old world we live in—in the UK we stubbornly still work with miles, yards and miles per hour on the roads. But while road signs giving warnings of an exit of a motorway are marked 600 yards, 400 yards, 200 yards….. legally they have to be placed 200 metres apart. We buy pints of beer in the pub (though not as often as I would like these days), but buy cans of beer in the supermarket in ml and litres. I know there are similar contradictions in the USA, Canada etc. None of which is an excuse, just an observation. I spend a lot of time proofreading my newsletters, but I am always happy when readers pick me up on typos or question some of the facts. It’s all part of the fun. You are the first to spot this one, so thank you. Let’s see if I can avoid the same mistake in future. Enjoy the rest of your Sunday. Best wishes. Steve.