 Hi, my name is John Evans and I'm a professor here at the Australian National University where I lecture in plant science at the Research School of Biology. One of the courses that I lecture into shows students what cells are made of and we utilise microscopes to study that. Now as a child, one of the wonderful things to discover is using a magnifying glass and being able to see things that you can't see with your naked eye and the reason for magnifying glass works is because suddenly it enlarges whatever you're looking at and you can see detail that you can't normally see. So how did this come about? Well maybe 400 years ago Galileo was inventing a telescope which he used to look at stars, be able to resolve the night sky and see stars that we can't see with a naked eye. And if you turn a telescope round the wrong way and look down it and make a few little changes suddenly you can use it to look at small objects. And Galileo actually used this to look at a fly and discovered that the surface of the fly is covered with fur or lots of little hairs. Now a microscope can be developed from combining glass lenses and the light passing through those lenses allows you to see small objects. And about 400 years ago in England a guy called Hooke used a compound microscope which is two sets of lenses joined together and he was a very good artist and he was looking at things like fleas and he could draw beautifully detailed pictures of what he saw and he published a book with these and suddenly the public got really excited to suddenly discover what these annoying little creatures that were on their dogs and on their own skin causing itching really looked like up close and they're quite frightening when you see them all these hairs and the claws that dig into your skin and make it itchy. In this book that Hooke produced he described how to make a microscope and in Holland at that time there was a man whose business was selling cloth who was really interested in how fine the threads were that went to make up the material and he was very interested to see if he could use a microscope to look in detail at the fineness of his cloth and he found that the microscope that Hooke described only allowed you to magnify to a limited extent and so he started developing his own type of microscope which was a much simpler design but allowed a much greater magnification. So this man's name was Lewin Hooke and he took information from Hooke's micrographia book for example slicing pieces of cork very very thinly and made his observations with his microscope and sent those observations to the Royal Society in London. At first the letters when they were received there was a lot of skepticism that you could actually really see that much detail because previously this had been never described before and in fact the fellows of the Royal Society were so skeptical they sent a delegation over to Holland to actually to see for themselves what what was being written about that the microscope's actually quite that Lewin Hooke used is quite difficult to use because it's very small and we'll show you that in the next video but essentially the people that visited Lewin Hooke confirmed that he was actually able to see what was described and then there followed something like 50 years of correspondence from Lewin Hooke to the Royal Society in London where he presented the findings as they unfolded.