Page [84.] The second at was removed from “strength of 2° Baumé at at a temperature”.

Page [103.] Changed zince to zinc, in “take the zince plate”.

Page [134.] Changed “throughly melted” to “thoroughly melted”.

Page [140.] Changed “with a a glue roller” to “with a glue roller”.

Page [141.] Changed “difcult to handle” to “difficult to handle”.

Page [182,] entry Exposure. Changed “timeing” to “timing”. Likewise, on page [184,] the entry Timeing was changed to Timing.