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Transcriber's Notes
1. Simple and obvious typographical errors have been corrected.
2. In the article "Manufacture of Photosensitive Plates", the original text referred to room U twice. The first instance has been changed to room T.
3. In the article "An Improved Screw Propeller", the text refers to the propeller in figure A as being four bladed and also two bladed. It is clearly two bladed and the reference to it being four-bladed has been corrected.