ACKNOWLEDGEMENTS

I especially wish to thank my supervisor Prof. Dr. N. Rowan for her help and good advice. Furthermore, I am very much indebted to Mrs De Ruyck-De Groote for typing this dissertation. (Deciphering my handwriting must have been an ordeal to her). I am also very grateful for the support and stimulation of my parents. And many thanks to my friend Ward and my girl friend Monica for their assis­tance and advice.

Motto: 

'Tis with our judgements as our watches; none.
Go just alike, yet each be­lieves his own."

Alexander Pope, An Essay on Criticism (line 9 and 10)