Copyright 1995 L. Hodgett. This material may be FREELY copied for private use or for distribution without charge but MUST NOT be used commercially without written permission from the compiler -- L. Hodgett. All of Mr Darby's very extensive writings including many hitherto unavailable articles may be obtained on CD from L. Hodgett, 7 Primrose Way, Cliffsend, Ramsgate, Kent CT12 5LF U.K. Tel/Fax: (0) 1843 584686, Email 101320.1236@CompuServe.com. Web Site http://visitweb.com/stem_publishing