Hello Pauline & all,
Thanks for the post, I have taken my children up to the Science Museum to see the
Compass in question a few times, really great for them (Prismatic Compass, he invented patented it 1812) he is my 4th Generation GreatGrandfather, isn't the internet and the information it has amazing, I must admit though I did a lot of hard work at the London Metropolitan Archives to find the connection with the family and early spelling of surname, I can remember my uncle in the 70's trying to link and trace the family tree with not much luck, if he had known what I have now found out I think he would have been fascinated, really it has only taken me about 4 years to go back to 1460 in Marburg Germany with the Schmalkalder Family, have my own Website and still have that passion to explore the wealth of information there is.
Many Thanks
Steven