A Crucial Leavening of ExpertiseEngineer Soldiers and the Transmission of Military Proficiency in the American Civil War Mark A. Smith (bio) Current scholarship on Union military engineering in the Civil War legitimately emphasizes its improvisational nature. In Northern armies of both theaters, volunteer soldiers with experience in mechanical or skilled trades improvised solutions to engineering problems. They built roads, bridges, and field works as needed to support military operations. Historian Thomas F. Army Jr. has even argued that the ability of Northern armies to concoct these solutions on the fly was a key reason for ultimate Union victory and a reflection of the North’s particular industrial and educational culture. There is, however, an important qualification to the improvisational nature of Union engineering that nearly all historians of the subject acknowledge: experience. It took time for the volunteers to develop the necessary expertise, especially in the peculiarly military aspects of the problems they faced. Road building, general bridge construction, and railroad management were all components of military engineering that had direct civilian analogs; skills in these endeavors found immediate application in military operations. Other facets, however, such as the construction of field works, siege works, and pontoon bridges, had no comparable component in the civilian world, and federal volunteers needed time to master or improvise these new skills.1 [End Page 9] In the western armies, as both Edward Hagerman and, more recently, Justin S. Solonick have noted, there were considerably fewer trained engineers to accelerate this process of converting volunteers into military engineers, but by late 1861 the eastern Army of the Potomac included an engineering component that could provide expertise until the improvisational ability of Union volunteers developed and could also accelerate the improvement of volunteer engineering proficiency. The soldiers of this component, distinct from their officers, went by many names: engineer troops, engineer soldiers, and sometimes, based on their special skills, sappers, miners, pontoniers, or some combination thereof; often, the simple, single term sapper was used generically for all engineer soldiers.2 Whatever they were called, their numbers were infinitesimal compared to the line troops of the three combat arms. Even in the Army of the Potomac and early in the war, before Northern volunteers had developed their improvised capability for field engineering, the sappers simply did not have the numbers to erect all the works the engineer officers planned. Their primary contribution came in another form. Despite one historian’s assertion that there was little distinction between engineer troops and the volunteers in the line, the sappers were the purveyors of special, inherently military skills that they had honed in the antebellum era and that they deployed using processes first developed in the war with Mexico.3 During the Civil War, these skills and processes were shared by one prewar engineer unit, Company A Corps of Engineers, with new regular army engineer companies and with improvised volunteer units. All these organizations subsequently deployed their knowledge to maximize its effects by supervising work parties drawn from line units to build bridges and field works. The sappers and their oversight provided a crucial leavening of military engineering expertise early in the war that directly supported military objectives and simultaneously accelerated the development of an improvised [End Page 10] engineering capacity by delivering practical albeit incidental instruction to line volunteers who served in fatigue parties. Moreover, the sappers’ experience, from their beginnings in 1846 through the end of the siegelike operations around Yorktown, illustrates the mechanisms by which military expertise was preserved and spread in the mid-nineteenth-century army. While their skills were unique and uniquely military, the ways the engineers maintained them in peace and shared them in war demonstrate how the capabilities and experience of long-term regular soldiers could be transmitted to a much larger volunteer force. Though the Union government opted to keep the regular army intact rather than dispersing its skills throughout the state-raised volunteer forces, the activities of the engineer soldiers reveal the importance of the regular army as a core of competent professionals who could provide critical skills while volunteers trained and that could assist in that training. ________ Congress created the antebellum engineer company just days after the...