Anyone who has read the notes in Heath's edition of Euclid's Elements is familiar with the name of Robert Simson whom Heath treats with the greatest respect. I never expected to see a copy of Simson's Elements of Euclid, but now have one, or rather a pdf scanned and made available to me free by the evil, greedy capitalists at Google. You may find this at: http://books.google.com/books?id=ZacAAAAAMAAJ . This seems to be the thirteenth edition (1806) although printed in 1821 in Philadelphia. The original is from the NY Public Library and seems to be in rather poor condition. There are several pages missing.
The file is named The_Elements_of_Euclid.pdf but is actually misnamed because the book contains also Euclid's Data, which is otherwise very difficult to find. There are some pages missing, which, unfortunately includes the definitions. Fortunately these (alone) are available in Ivor Thomas Greek Mathematical Works. Also Heath mentions most of them in his History of Greek Mathematics vol. 1.
I should mention here Marinus Taisbak's book Dedomena. I had it from the library some years ago and can recommend it. He provides all the Greek and an excellent English translation. His commentary would be illuminating, if I understood it.
Simson's book provides no table of contents, and since it is clumsy to navigate in a pdf, I made a table of contents below which you may find useful.
Regards, Bob Robert Eldon Taylor philologos at mindspring dot com
Contents of Simson's Euclid The_Elements_of_Euclid.pdf
Book PDF page page Title i 10 Preface iii 12 Bk I 7 16 Bk II 49 56 missing 64-65 Bk III-prop 1. 66 71 Bk IV 100 105 Bk V 117 122 missing 150-151 Bk VI 153 154 Bk XI 194 193 Bk XII 250 249 Notes 293 290 missing pages 334-335 missing pages 340-341 page 342 printed as 432 page 349 printed as 340 Euclid's Data 361 354 Preface 363 356 missing pages 364-365 Def. X 366 357 Notes on Data 461 450 Plane & Spherical 477 466 Plane 479 468 Spherical 514 503 last page 505