The original Silent artist is Dean Cornwell. Both Harlequin covers are unsigned.
The Valley of Silent Men cover was originally seen on the 1920 Cosmopolitan Books first edition. Heart of Asia's illustration is from the first edition published by Duell, Sloan and Pearce in 1951.
Harlequin 383 - March 1957
(also first printing #176 - June 1952)
Harlequin 291 - March 1954