There's an alleged first edition for sale in the USA (https://bit.ly/2ZqPp48), and the bibliographic run-down gives the following information:

Volume 1; published 1828, 7 plates. 530 pages, plus appendix. Volume 2; published 1829, 8 plates. 534 pages. Volume 3; published 1831, 12 plates. 640 pages. Volume 4; published 1834, 9 plates, 589 pages. Volume 5; published 1836, 8 plates 581 pages. Volume 6; published 1840, 10 plates, 688 pages.

A quick google suggests this is probably accurate, although someone else may know more!

Best wishes

Jacqueline