Thomas Smythe (aka Thomas Smyth and Thomas Smith) was a leading Southern Presbyterian who has unfortunately fallen into a degree of obscurity. Some of his background (and the source of the hot-linked image) can be found at the PCA's historical web site (link).
I am pleased to report that Smyth's works are now freely available (in electronic form) to the downloading public via Archive.org. The PCA's web site had indicated a digitization project with respect to Smyth, but I presume that part of this project will have been superseded through Archive.org's efforts in getting the ten volumes of Smythe's works digitized.
For a table of contents of the works (except volume 8, which apparently the PCA's digitization team did not have), please click this link.
The following are links to the individual pages for each of the volumes of Smythe's works:
Archive.org has also made available two copies of Smyth's "Ecclesiastical Catechism of the Presbyterian Church" (copy 1)(copy 2), piggybacking on the efforts of Google Books.
The PCA has itself made available some individual articles available:
The Call to the Ministry-Its Nature and Evidence, 2.2 (September 1848) 157-183.
The Necessity and Importance of Controversy, 7.1 (July 1853) 60-74.
Recall also the short selection we previously identified, provided by the Virginia Hugenot (link).