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2. The London Encyclopaedia or Universal Dictionary of Science Art Literature and Practical Mechanics Vol. 5 Thomas Tegg London 1829 p. 359; https://books.google.com.au/books?id=wc 6bzoXx1kC&pg=PA359&lpg=PA359&dq=oil+of+vitriol+basil+valentine&source=bl&ots=1lJM0tBZGc&sig=l9-gsw6WNWigXIT9SD-be2l3j5A&hl=en&sa=X&ved=0ahUKEwiwhtSowt3SAhXDpZQKHTA DfkQ6AEIOjAF#v=onepage&q=oil%20of%20vitriol%20basil%20valentine&f=false (accessed April 1 2017).