Rev. William Spencer Campbell (1859-1939) served as minister of the Milton Presbyterian Church (Milton, Caswell County, NC) 1891-1896, being the tenth person to hold that position.
He is a son of Rev. William Addison Campbell of Richmond, VA (1829-1896). Note the sender of the above 1892 envelope/letter is Rev. W. A. Campbell, 319 W. Grace St., Richmond, VA. Click the image to see a larger version.
For a brief church history go to Milton Presbyterian Church
The Evening Times (Washington, D.C.) June 10, 1896 page 8:
"Richmond, Va., June 10.—Rev. Dr. W. A. Campbell, the well-known Presbyterian minister and writer, died at his residence last night in this city. He had been in failing health since the early part of the year, but his condition was not considered alarming unit a few days ago.
"Dr. Campbell was a man of find character and unusual natural gifts. He had filled many important pastorates, and was for several years evangelist of the synod of Virginia; was for some time traveling agent of the Virginia Bible Society, and on the death last year of Mr. T. D. T. Walford became secretary of the society. He was also secretary of the peace conference. Dr. Campbell leaves a wife and five children."