Inconsistencies in the source document have been retained.
Depending on the hard- and software used, not all elements may display as intended.
Page 59, table: the row Tin 6 does not add up to 100 (%, presumably) as the other rows do.
Minor obvious punctuation errors have been corrected silently.
Page 5: 66° and 34° have been changed to 66% and 34%, respectively.
Page 7: flow over the hoe has been changed to flow over the hole.
Page 154: enter at last has been changed to enter at least.