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.