Copy letter from A H White, to Professor Harold Baily Dixon, Fellow of the Royal Society, Chemical Department, the University, Manchester 'Dear Sir, Could you supply for engravers assistance the negatives of the 2 unsatisfactory figures illustrating the explosion paper. The engravers (Alexander & Co of Shoe Lane) will write to you direct, & perhaps you will send the negatives direct to them. AHW'. 27 March 1907