1. A few punctuation errors have been corrected.

2. The words with ligature and diacritical marks have been standardized.

3. The following misprints have been corrected:
"adressed" changed to "addressed" (page 136)
"minimun" changed to "minimum" (page 142)
"desended" changed to "descended" (page 143)
"behing" changed to "behind" (page 144)
"converion" changed to "conversion" (page 148)
"enviroment" changed to "environment" (page 149)

4. Other than these, no other changes have been made in the original text.