In "Electrons and Holes", 1st paragraph, 2nd sentence, "usefull" should be "useful".

Same misspelling in the 2nd paragraph below the first figure.

In the paragraph just before the "Marble in a Tube" figure, next-to-last sentence, "in inthe" needs changing.

In the 2nd sentence below the "Marble in a Tube" figure, "must be move" should be "must be moved".

In the last sentence in this paragraph "appearant" should be "apparent".

 

Thanks for the corrections. They have been entered in the master copy at ibiblio