He was the pioneer of scientific horticulture and agriculture in the state. Defeated for Congress in 1851, Mr. Langdon soon afterward sold his journal and retired to a farm in the western part of Mobile County to demonstrate his method of scientific farming, which, at that time, was a subject of ridicule. He was called from his seclusion by the stirring political scenes of 1860, and appeared on the hustings as an ardent advocate of Bell and Everett. Though a stout opponent of secession, when it came and brought with it its consequences he was just as ardent in his espousal of the cause of the South as was any. Both by pen and by word of mouth he supported the cause throughout, and came to be one of the most popular citizens of Mobile and one of the most conspicuous public men in the state. He was chosen to represent the county of Mobile in the legislature in 1861, and in a trying period rendered most valuable service. In 1865 he was chosen to represent the Mobile district in Congress, but he was denied his seat by the party in power, and was shortly afterward disfranchised. Under these conditions he retired to his country seat near Citronelle, where he continued to demonstrate in a scientific way the results of horticulture and agriculture. In a period of rehabilitation in the South Mr. Langdon made frequent exhibition of the results of his efforts, and with patriotic zeal inspired the public with confidence in the capabilities and productiveness of the soils in a climate so bland, and insisted that if properly tilled, the fields of the South would make her more independent than she had ever been. In 1877 Colonel Langdon became a candidate for the governorship against Honorable Rufus W. Cobb, the latter of whom was chosen. It was remarkable the difference between the appearances of the two candidates before the state convention of nomination. Mr. Cobb wore a cheap colored suit of clothes, in illustration of his ardent democracy, while Colonel Langdon was arrayed in a beautiful suit of black cloth, with a Prince Albert coat, all fresh and costly from the tailor's hands. The one immediately following the other in speeches before the body, presented a contrast of appearance at once striking and remarkable. The scene thus presented became a subject of general comment among the members of the convention. The frequent contributions of Colonel Langdon to the press relative to horticultural and agricultural processes and results had much to do, after the close of the war, with the reawakening of the spirit which has eventuated in the abandonment of old and worn methods of cultivation, and in the adoption of new ones, which have brought untold wealth to the state.