Ken,
Happy to help! The book *is* definitely available from various sources, and the text is in the public domain so there are text based versions available on the internet too. There have been many reprints and editions since the original 1769 print, the most recent I believe is from 2003. Mine is a reprint from the 1780 edition.
http://www.ageofnelson.org/Document11.htmlhas links to a massive 500mb pdf download, and also a link to a searchable version of it as a web page, but the online version I did not find to be too enjoyable to refer to because of a great number of OCR issues.
A reprint of the 1780 edition is available on Amazon for $75/£40, and there are various other bookstores out there selling used versions of various editions.
It is also worth checking your local or regional library as they may hold a copy that you could refer to!
Failing all of that, I'm happy to look up and scan any definitions you might need!
Amy