Bill Daehn, author of an important bibliography on Greek Numismatics, has a small web site. His site includes a very useful table of Greek weight standards that has been helpful to me. The site includes many of his articles. A good one is his Asylum article on his copy of Pinkerton's An Essay on Medals (1808)

If reading Daehn's essay makes you interested in Pinkerton's book both volume 1 and volume 2 can be viewed and downloaded from Google Books.

If you believe, as Daehn does, “When holding and reading an original edition, the collector feels a closer connection to the time and place in which the book was written. In comparison, the reprint feels ‘too modern,’ and part of that all-important connection is lost” you'll be happy to know that sellers on AbeBooks.com are offering Pinkerton two-volume sets, both 1st editions and the 1808 reprint, at prices ranging from $37 to $316.