Were they also in Fredericksburg, Texas?
Looks like you're onto something there--I found this by Googling on "Vierziger Texas Fredericksburg":
With the secessionqv of Texas in 1861, Kuechler was commissioned by Sam Houstonqv as captain to enroll state militia troops in Gillespie County. He signed up only German Unionists in his frontier company, and it was dismissed by Governor Francis R. Lubbock.qv Kuechler then served as a guide for German Unionists attempting to flee to Mexico and survived the battle of the Nueces.qv He remained in exile in Mexico during the rest of the war and worked as a surveyor in the northern Mexican states until the end of 1867. Upon his return to Texas he was appointed deputy collector of customs at San Antonio. He was elected a delegate to the state Constitutional Convention of 1868-69qv and became a leading spokesman for Germansqv in the Republican partyqv during Reconstruction.qv Kuechler was elected and served as commissioner of the General Land Office from 1870 until 1874. Thereafter, he surveyed land along the Devils and Pecos rivers for the International-Great Northern and the Gulf, Western Texas and Pacific railroads. He was appointed principal surveyor for the Texas and Pacific Railroad Company in 1878 and worked in the Trans-Pecos region. Kuechler and his wife and son (two sons had died earlier) visited the German Empire in 1887. Kuechler died in Austin on April 4, 1893, and was buried in Oakwood Cemetery. BIBLIOGRAPHY: Rudolph L. Biesele, The History of the German Settlements in Texas, 1831-1861 (Austin: Von Boeckmann-Jones, 1930; rpt. 1964). J. J. Bowden, Surveying the Texas and Pacific Land Grant West of the Pecos River (Southwestern Studies 46 [El Paso: Texas Western Press, 1975]). Jacob Kuechler Papers, Barker Texas History Center, University of Texas at Austin. Solms-Braunfels Archives (transcripts, Sophienburg Museum, New Braunfels, Texas; Barker Texas History Center, University of Texas at Austin). James Patrick McGuire
KUECHLER, JACOB (1823-1893). Jacob Kuechler, surveyor, Union officer, and commissioner of the General Land Office,qv was born in Schoellenbach, Hesse-Darmstadt, on February 18, 1823, son of Albrecht Kuechler, an engineering and forestry official. Jacob Kuechler graduated from the University of Giessen with a degree in civil engineering and forestry and traveled to Texas in 1847 with the Darmstadt colony (also called the Vierziger, the Forty), a group of young graduates of the universities of Giessen and Heidelberg and the Gewerbeschule of Darmstadt. The Vierziger had contracted with the Adelsvereinqv to begin a colony in the Fisher-Miller land grantqv north of the Llano River and founded the utopian socialist community Bettinaqv late in 1847. The new settlement had disappeared by the next summer, and Kuechler, listed as a forester, settled at Fredericksburg. He became a citizen on October 10, 1853, and married Marie Petri, sister of the pioneer artist Richard Petri,qv in May 1856. He thereafter farmed with Hermann Lungkwitz,qv pioneer landscape artist who lived in the Live Oak community on the Pedernales River near Fredericksburg. Kuechler also became a surveyor and served Gillespie County in this capacity until the outbreak of the Civil War.qv He pioneered tree-ring study at Fredericksburg during the drought of the late 1850s. He compared dry and wet years from rings of post oaks going back to 1727 to find evidence of the agricultural conditions in the Hill Country.qv His study was published as "Das Klima von Texas" in Gustav Schleicher'sqv Texas Staats-Zeitung (San Antonio) in 1859 and in the Texas Almanacqv two years later.