What is a theodolite? a device for measuring angles from the ground to distant objects so one can work out their height and distance
Using an instrument like the one below Joseph was able to work out that Mount Donkia was 23,176 feet high and 73 miles away (which he later climbed) from Brian Hodgson's house where Joseph was staying. He also saw and drew Mount Everest and worked out it was over 28,000 feet high - the first person to do this. Joseph Dawson Hooker named a lovely Rhododendron after Brian and this is being planted in our Town Park see below.