Page 8: ... a filament or tungsten ... changed to ... a filament of tungsten .... Page 35: ... release on ringer ... changed to ... release on wringer .... Page 36: ... six drying rods 66′ long ... changed to ... six drying rods 66″ long .... Page 37: ... new avid air ... changed to ... new arid air .... Page 57: closing quote mark inserted after ... running and installation costs? Page 68-69: ... a figure out of the unit ... changed to ... a figure but of the unit .... Page 74: ... oven arrangement and unit system is so arranged ... changed to ... oven arrangement and unit system are so arranged .... Illustration after page 74: _Courtesy of Brainhall Leane Co._ changed to _Courtesy of Bramhall Deane Co._ Page 141, table: Branch wastes for slop sinks changed to Branch waste for slop sinks. Page 245: ... is varnish and finish steamproof ... changed to ... is varnished and finished steamproof .... Page 260: comma inserted after ... for they hold enough water Page 335: Heading Principles changed to PRINCIPLES. Page 359: Temperature effect densities ... changed to Temperature affects densities ....