Chapter 1: The Genesis of a Small Corps

In 1845 the United States faced two international problems: a dispute with Great Britain over Oregon, and Mexico's opposition to the annexation of Texas. Either could have led to war. Fortunately, by the following year the United States reached an agreement with Great Britain over Oregon. But the quarrel with Mexico moved one step closer to war on 1 March 1845, when Congress resolved to admit Texas to the Union.1

While Polk waited for Texas to accept the offer of statehood orders went out alerting military commanders to prepare for possible hostilities with Mexico. The Navy concentrated in Texan and Mexican waters, and the Pacific Squadron received instructions to prepare to seize ports along the California coast. In June, orders reached Bvt. Gen. Zachary Taylor and his "Corps of Observation" at Fort Jesup, Louisiana, to move to a position "on or near the Rio Grande well suited to repel any invasion." Instead, Taylor moved his army by land and sea to Corpus Christi, avoiding the disputed border region.2

In July Texas' agreement to annexation created more war jitters. Secretary of War William L. Marcy dispatched more troops to Texas, and authorized Taylor to call upon the governors of nearby states for militia. Polk sought to negotiate a settlement on American terms, seeking to define a Rio Grande boundary and to purchase Upper California and New Mexico. The Mexican government, however, had no intention of giving up half of its national territory.

When notified of the Mexican government's refusal to negotiate, Polk, in January 1846, ordered Taylor to move his force to the Rio Grande as soon as possible. Taylor, called "Old Rough and Ready" by his troops, acknowledged the order and its instructions not to consider Mexico as an enemy. He was not to take action unless a declaration of war took place or American forces came under attack.

Events, however, did lead to the Mexican War, America's first foreign war fought almost entirely in a strange and distant land. During the war a small group of uniformed topographers, or "topogs," of the U.S. Army Corps of Topographical Engineers served with distinction. This is the story of a unique organization, particularly its members, and its contribution to the nation, not only in the war with Mexico but as an agency for internal development.

Although the public knew little about the work of the Corps of Topographical Engineers during the war, the corps contributed significantly to the victory of U.S. forces. Besides the topogs' military

contributions, the small corps of officers (the corps did not have enlisted personnel) achieved geographic and scientific discoveries, products of more lasting consequence. Their investigations, carried out in the midst of the war, broadened geographic knowledge about the little-known regions of the Southwest. In essence, the corps served as sort of an intelligence gathering agency.

Most of the topogs, 26 of the 46 officers on Army rolls between 1846 and 1848, served in or near combat zones. Other members of the corps provided indirect support to the war effort. Although the topogs served meritoriously in the theaters of war, their topographic and geographic studies and maps resulted in a singular accomplishment among the branches of the Army. Even in the midst of a war the Topographical Engineers maintained their interest in the sciences. By the very nature of their backgrounds, they could not resist noting their geographic surroundings.3

The topogs' efforts resulted in the most up-to-date and accurate maps of the regions they crossed, before, during, and following the war. Published accounts of the Topographical Engineers' travels also added significantly to the popular travel literature of the day. Accounts of the curious ways and customs of the Mexicans and Indians, their languages and heritage, the climate, the wild and barren topography, and exotic vegetation and wildlife lent an air of romanticism never before experienced by Americans. The Army topographers' accounts outlined the routes to California, Oregon, and the Southwest, revealing at the same time the potential of these newly acquired territories. As a result, the hordes of pioneers heading west after the wax put the writings of the Topographical Engineers to practical use.4

Two separate engineering corps existed in the U.S. Army at the time. Robert E. Lee, P. G. T. Beauregard, Henry W. Halleck, and George B. McClellan, all well known Civil War commanders,

served in the Corps of Engineers as captains and lieutenants during the Mexican War. The Corps of Topographical Engineers included other prominent Civil War leaders to be. George G. Meade, Joseph E. Johnston, John Pope, and John C. Fremont served as topog captains and lieutenants during the conflict with Mexico. Other veteran engineering officers of the two corps who served in the Mexican War also went on to positions of responsibility in the Army, in business, and in education.

The responsibilities of the Corps of Topographical Engineers included not only topography and mapping, but, just as significant, civil engineering works authorized by Congress. The civil engineering projects-roads, canals, railways, lighthouses, and public buildings and works-were a great share of the topographical corps' efforts. When war broke out, the Corps of Topographical Engineers found itself in the midst of a large construction effort. Military engineering support to armies in the field, however, and construction of fortifications remained with the Corps of Engineers.5

Mapping was an important responsibility of the Topographical Engineers. From the military commander's viewpoint accurate knowledge of the terrain often means the difference between success or failure on the battlefield. A military agency is often given the task of mapping its own country and obtaining the latest information on the geography and topography of other nations, which in modern terms is referred to as terrain intelligence. The scientific side benefits gathered by the topographers- general information about people, plant and animal life, minerals, and soil conditions- was also especially significant during this period of United States' expansions.6

Many of the duties of the topographers assigned to field commands were similar to those conducted by the Corps of Engineers. Army regulations in force between 1840 and 1857 specified that armies in the field would always have Topographical Engineers to help

. . . in reconnaissances of the country through which an army has to pass, or in which it has to operate; in the examination of all routes of communication by land or by water, both for supplies and for military move-

ments; in the construction of military roads and permanent bridges connected with them, and in the absence of an officer or officers of the Corps of Engineers, of military bridges, and of field works, for the defense of encampments, fords, ferries, and bridges.7

Although Army topographers worked for field commanders, they regularly forwarded reports to the chief of their corps. These reports covered matters of geographic, topographic, and other scientific studies, all items of the utmost interest to the topogs' headquarters in Washington. The high esprit de corps and personal scientific interests among members of the corps also served as an incentive to gather vast amounts of information about the regions they crossed.

In this period, in which the Topographical Engineers operated as a corps and separate branch of the Army, all but 8 of the 72 Army topographers who served between 1838 and 1863 obtained their commissions from the Military Academy. The majority of the Topographical Engineer officers also received their training in military engineering at West Point. Since the Corps of Engineers had responsibility for the Military Academy's operation, engineering and engineering-related subjects predominated in the school's curriculum. Courses included mathematics, drawing, military and civil engineering, history, geography, ethics, military science, some law, and French and Spanish. Officers graduated well versed in surveying; in the construction of buildings, roads, bridges, canals, and railroads; and in the improvement and building of harbors. Usually the top graduates received commissions in one of the two engineering branches.8

Two of the eight officers had attended the military academy but left before graduation to work in civilian life. One, Stephen H. Long, graduated from Dartmouth, however, he did serve at West Point as an instructor. John G. Fremont was also in this group. He received his credentials in the field and under the expert guidance

of Joseph N. Nicollet and Ferdinand Hassler. Of these eight Topographical Engineers, only Fremont seemed to resent West Point's apparent domination of the Army.9

The Corps of Topographical Engineers did not have a service school to provide further training to its officers. The topogs obtained their expertise in mapping and construction by on-the-job training, by travel, and by association with the scientists and engineers of the day. In addition, the corps instructed its supervisors to ensure that their junior officers received training in the skills of their trade. For example, in 1845 Bvt. Captain Fremont received specific instructions from Colonel John James Abert, the chief of the corps, on this point before setting out on his third trans-Mississippi expedition.10

The Topographical Engineers date back to the American Revolution when Robert Erskine received an appointment as "geographer" for General George Washington. Erskine died in 1780, and two positions were established, one for the northern wing of the Army and the other for the southern wing. As a result, the topographers served as a distinct group of engineers from the earliest days of the United States. Following the American Revolution, Congress retained one of the geographer positions, that of surveyor of the public lands, to comply with the provisions of the Land Ordinance of 1785. Although the Army did not have a topographic branch at the time, the expeditions of Captains Meriwether Lewis and William Clark, Lieutenant Zebulon Pike, and others served as models. The later expeditions of the Corps of

Topographical Engineers resembled in many ways these earlier Army ventures in the West.11

During the War of 1812 the Army greatly increased its number of military topographers. On 3 March 1813 an act of Congress authorized for the Army General Staff 16 topographical officer positions with ranks of brevet major and captain.12 This act, however, did not authorize a corps or any administrative capability. During the war the topographers served as staff officers in both the northern and southern wings of the Army. Significantly, two of the topogs who served in the war, Isaac Roberdeau and John James Abert, later went on to serve as chiefs of the Army topographers.13

Instructions issued to topogs during the war also served as a model for future operations. When assigned to armies in the field these officers were

To make such surveys, and exhibit such delineations of these as the commanding general shall direct; to make plans of all military positions (which the Army may occupy) and of their respective vicinities, indicating the various roads, rivers, creeks, ravines, hills, woods, and villages to be found therein; to accompany all reconnoitering parties sent out to obtain intelligence of the movements of the enemy or of his position, etc.; to make sketches of their route, accompanied by written notes of everything worthy of observation thereon; to keep a journal of every day's movements, when the Army is on march, noticing the varieties of ground, of buildings, of culture, and the distances and state of the road between given points throughout the march of the day and, lastly, to exhibit the positions of contending armies on fields of battle, and disposition made, whether for attack or defense.14

The conclusion of the war led to the usual reduction in military personnel. In authorizing the smaller military establishment following the wax, Congress provided for a Corps of Engineers but made no mention of Topographical Engineers. Two topogs (including Isaac Roberdeau) remained on active duty to complete surveys on the northern frontier and Lake Champlain. The two topogs saw an immense task ahead after the border survey. In their report they recommended "the completion of a frontier military survey of the whole interior and exterior of the United States."15

Recognizing the need for Topographical Engineers in military operations, Congress in 1816 passed a law authorizing ten officers. Significantly, this legislation provided for the first time several Army topographers during peacetime. Unlike the Corps of Engineers the topographical officers continued to lack a central office or branch status as a separate corps. Generally, the War Department assigned them as staff officers to the two military departments. A few topographers also found themselves working for the Board of Engineers for Fortifications. In this role the Army topographers surveyed the sites for seacoast and inland fortifications. A side benefit of these surveys also resulted in later improvements to navigation. Farther inland Major Stephen H. Long, one of the noted topogs of the period, established Fort Smith in Arkansas and explored the Old Northwest for future fortification sites.16

In 1818 the War Department consolidated the Corps of Engineers, the Topographical Engineers, the U.S. Military Academy, and the Board of Engineers for Fortifications into a single Engineer Department headed by the senior Corps of Engineers officer. Under

the direction of Major Roberdeau the topogs became part of a subordinate Topographical Bureau. Located in Washington, the bureau's main duties consisted of housekeeping tasks but not control over programs or personnel. The bureau collected and preserved the specimens brought back by scientific expeditions, compiled maps, and stored and cared for the topogs' survey instruments.17

Under the Engineer Department the Topographical Engineers continued their normal work, in some cases working on related or identical projects with Corps of Engineers' officers. In 1819 and 1820 Major Stephen Long led an expedition to the Rocky Mountains, but his somewhat negative report of the high plains region created the "Great American Desert" myth. While Long explored the trans-Mississippi West, two Engineer officers surveyed the lower Mississippi. A topographer served on General Andrew Jackson's military operation against the Seminole Indians in Florida. Several topogs and Engineers surveyed harbors and bays, formally known as the Survey of the Coast, a joint effort that continued for several years thereafter. The topogs dominated the boundary surveys. In 1823 Major Long determined the northern boundary between the United States and Canada at the 49th parallel in Minnesota.18

The placement of the Army topographers under the Engineer Department heightened the already strained relations with the Corps of Engineers. Some problems between the two groups of Army engineers had occurred while working on similar or related projects. This partly stemmed from the class standing upon graduation from West Point; the top ranks of the graduating class received assignments to the Corps of Engineers closely followed by the second ranking group, the topogs. Corps of Engineers' officers tended to believe that greater skills were necessary in the planning and construction of fortifications than for public works. Engineer officers also made sure they ran the Engineer Department. In the absence of the Chief of Engineers an Engineer captain or sometimes even a lieutenant, not Major Roberdeau, took over the department. Stephen Long took a dim view of the topogs' apparent

second-class status, and he believed Engineer officers "cordially hate or more probably are jealous of our rising reputation." 19

By 1824 the importance of waterways became paramount in the development of the young nation's commerce. By this time too the federal government, following the Supreme Court decision in the Gibbons versus Ogden case, had asserted its role in interstate commerce and the improving of the country's transportation system, particularly the rivers, canals, and harbors. In order to better develop the vast lands beyond the Appalachians, the young nation desperately needed to improve navigable passageways. Congress, in recognition of an increased government commitment to internal improvements, passed legislation which involved using the Army's engineers to do the work. The General Survey Act of 1824 initially called for field surveys, plans, and estimates of roads and canals, but within a month a second law appropriated funds and authorized the employment of necessary Army engineers to improve the navigation of the Ohio and Mississippi rivers. Besides, Congress believed the soldier-engineers would obtain experience and do something useful to enhance the country's defenses and development. From that point both the Corps of Engineers and the Topographical Engineers became deeply involved in civil works.20

By the end of May President James Monroe appointed a Board of Engineers for Internal Improvements to administer the General Survey Act. Its members included Corps of Engineers' officers but no Topographical Engineers. The topogs felt frustrated by the lack of recognition, and Major Long asked Roberdeau if the topographers were "to be mere chain bearers in the giant work of internal improvement." Three topogs, however, were attached to the board to lead survey parties to evaluate canal routes. The survey work dramatically influenced the topogs' outlook on their mission. Authorized ten officers to do military reconnaissances and make maps, the topogs instead devoted almost all their efforts to inter-

nal improvements. By 1830 topogs led 10 of the 13 surveys for canal, road, and railroads, while civilians headed the other 3. Although the Engineer Department took care of general supervision of the surveys and the navigation work on the Mississippi and Ohio rivers, the topogs accomplished the great share of the field work. Scattered as they were throughout the interior of the country, the topographers began to earn a national reputation for their internal improvement work.21

In 1826 further legislation added more surveys for harbor and river improvements and significantly the authorization to carry out the actual work. On the Ohio River near Henderson, Kentucky, Major Long supervised the construction of a wing dam which reduced a sandbar and raised the water for navigation. Later the engineers supervised commercially developed steam-powered snagboats to clear the rivers of hazardous limbs and debris, thereby improving navigation. Now for the first time boats could be safely operated at night. Other survey work included the Chesapeake and Ohio Canal, a trans-Florida canal, and the Cumberland Road. Demands for similar services were so great that the War Department employed civil engineers and detailed additional officers with engineering skills from other branches of the Army.22

In January 1829 Bvt. Lt. Col. Isaac Roberdeau suddenly died, and after some deliberation Major John J. Abert took over the reins of the Topographical Bureau. The following year he succeeded in gaining representation on the Board of Internal Improvements. The board's usefulness, however, had diminished once it had identified the required survey work, and in 1831 the Secretary of War abolished the board. In a dramatic move for the

topogs the secretary also transferred the board's responsibilities to the Topographical Bureau and elevated the bureau to independent status within the War Department.23

When Brevet Colonel Abert took over the Topographical Bureau, he began working in earnest to establish first an independent bureau followed by the establishment of a separate Corps of Topographical Engineers. He argued that the distinct duties between both kinds of engineers- topographers and fortifications engineers- were important enough to justify two separate corps. The Chief Engineer, Colonel Charles Gratiot, did not agree, arguing that surveys and construction were inseparable. As a slight concession, however, Abert received an appointment as assistant to the Chief Engineer for topographic matters. The following year he became a member of the Board of Engineers for Internal Improvements. At first Abert's role as an assistant chief still denied him complete control over topographic operations until his appointment to the Board of Engineers for Internal Improvements as coordinator of its operations. With the closing down of the board two years later Abert finally succeeded in getting the War Department to make the bureau a separate office directly responsible to the Secretary of War. Now free of direct Engineer Department control, Abert came one step closer to his goal of establishing a Corps of Topographical Engineers.24

Now for the first time a centralized Topographical Bureau controlled its own personnel and stood on an equal footing with the Engineer Department and the other elements of the Army staff. The duties of the bureau as outlined by the War Department were both military and civil. It continued to act as a topographic repository and took charge of military surveys and reconnaissances and the management of internal improvements. To overcome the limited officer strength authorization, the bureau continued the prac-

tice of hiring civilian surveyors and borrowing infantry and artillery officers to do the surveys. The responsibilities taken over from the Board of Engineers for Internal Improvements included the supervision of over 50 personnel-12 civil engineers, 30 line officers, and Abert's own 10 topogs and a few attached Engineers. Up until 1836 the Corps of Engineers handled all river and harbor construction projects, but that year the War Department transferred several Great Lakes and Lake Champlain projects to the Topographical Bureau. In this manner Abert's mixed force of topogs proceeded to accomplish field surveys and some of the construction responsibilities for internal improvements.25

Soon the small bureau became overloaded with civil engineering projects. By 1838 construction activities had increased immensely and surpassed surveying in importance. The topogs were also helping the new railroads, a somewhat controversial practice, by doing surveys and supervising some construction. The system of detailing officers from other branches to the hard-pressed Topographical Bureau began to reveal drawbacks, particularly when requirements for the Seminole War resulted in the withdrawal of the detailed officers from the internal improvements work. The campaign against the Indians in Florida also demanded the services of topogs in the field and the preparation of a map of the peninsula. Several topogs remained in Florida through the 1840s, working on roads and improving the map.26

Other engineering requirements drew on the skills of the Topographical Engineers. In 1834 the bureau took on the construction of coastal lighthouses for the Treasury Department. The Treasury Department also reestablished the Coast Survey in 1836, and the project absorbed more of the Topographical Bureau's limited capability. Thereafter, until the abolishment of the Corps of Topographical Engineers in 1863 as a separate corps, one or more officers remained assigned to this survey.27

In the meantime, Abert continued to pursue his goal to elevate his bureau to corps status. Although the bureau assumed the responsibility for the surveys for internal improvements, Congress and the War Department had failed to delineate the duties of the Corps of Engineers and the Topographical Bureau. Measures in Congress to establish the separate corps failed in 1836 and 1837 before finally passing in 1838. The Seminole War and the expansion of the western frontier prompted Congress to enact legislation to increase the size and improve the efficiency of the military establishment. This logically led to the establishment of the Corps of Topographical Engineers, and the law defined the duties of the two engineering corps. The topogs took on all the civil engineering works directed by the federal government, especially the improvements for rivers and harbors. The Corps of Engineers retained military construction projects, primarily the construction of coastal fortifications. In turn, the Topographical Engineers transferred to the Corps of Engineers its plans and drawings of fortifications.28

The act of 5 July 1838 establishing the new corps authorized a total of 36 officers but no enlisted personnel. More specifically, the act of Congress authorized a 36-man topographical engineering corps to "consist of one colonel, one lieutenant colonel, four majors, ten captains, ten first lieutenants, and ten second lieutenants." Colonel Abert became the chief of the corps and as such became equal in rank to all the other heads of Army services, including the Chief of Engineers. The act also ended the corps' dependence on civilian engineers.29

As a result of this reorganization, the operations of the Topographical Engineers expanded rapidly. The topogs assumed all responsibility for river and harbor improvements on the Mississippi, Ohio, Missouri, Arkansas, and Red rivers and in many harbors on the

Atlantic and Gulf coasts and on the Great Lakes. Surveying of the Great Lakes intensified on a systematic basis in 1841. Topogs supervised the road-building projects in Wisconsin, Iowa, Michigan, Arkansas, and Florida. Ostensibly built for military purposes, these roads also eased the westward migration and delivery of mail, agriculture produce, and other commerce. Several topogs also reported to the State Department to work on various boundary surveys along the international borders, including the Texas Boundary Survey (1840-1841) and the Northeast Boundary Survey (1840-1850). By 1845 seven topogs were at work surveying the New Brunswick-Maine boundary. Other members of the corps supervised the construction of new military roads in the territories. In Washington the corps embarked on several important public works projects. Topogs resumed work on the long-delayed Washington Monument, began constructing an aqueduct in the Georgetown area of the District of Columbia, and started paving Pennsylvania Avenue between the Capitol and the White House. The topographers also found time to help the Corps of Engineers' military construction program by surveying potential fortification sites and reconnoitering strategic locations.30

In the 1840s the Topographical Engineers began a long series of military surveys. Surveys for defensive purposes were underway for the harbor at Portsmouth, New Hampshire, and roads to and from Washington, D.C. Very extensive surveys were also made around New Orleans and in Florida to include the Dry Tortugas and Key West harbor. Although well established in its public works role, the corps increased its role in western exploration and mapping.31

As the tension increased between the United States and Mexico in 1845, one of the topogs, Bvt. Captain John C. Fremont, prepared to depart on his third expedition to the West. Although strong American expansionist aspirations prompted the acquisition of the

territories of California and New Mexico either by negotiation or by force, very little information and few reliable maps were available for military operations. The United States still knew very little about its own lands west of the Mississippi, a vast expanse of territory acquired years earlier as a result of the Louisiana Purchase in 1803.32

This requirement for geographic information turned the corps' attention to increasing its mapping of the West, and this in turn presented new opportunities for exploration. Except for Stephen H. Long, now an older major engaged in river improvement work, only Fremont had any significant exploration experience west of the Mississippi. East of the river the corps had paid particular attention to its role as a government engineering, public works, and construction agency. Now necessity prompted the corps' involvement westward.

Several concerns in the West confronted President Polk's new administration. First, restless Indian tribes needed to be appeased. In particular, the mobile, horse-mounted Indians of the western plains preyed on unescorted settlers and traders passing through their territories. Second, accurate maps for military purposes were either lacking or inadequate. As a result, an urgent requirement induced military planners to launch a series of military expeditions to gather information about the areas in contention with Mexico. Third, the movement of armies and their logistical trains required a knowledge of existing and proposed routes for transporting supplies.

At the time the corps had only a single map of the entire trans-Mississippi West, an unpublished 1844 map of Texas compiled by 1st Lt. William H. Emory from available sources. Josiah Gregg's Commerce of the Prairies (1844) and Tanner's American Atlas (1839) offered some reliable information, but generally the commercial maps, largely based on hearsay and conjecture, were woefully inaccurate. Even Emory's map relied on less than accurate information. The forthcoming maps resulting from Fremont's 1843-1844 expedition tracing the route along the Oregon Trail were still in preparation. For the most part the available maps proved unsatisfactory for use by military commanders in the field. As a result, the Army had to rely on military expeditions to reconnoiter and map the terrain, a responsibility of the Corps of Topographical Engineers.

During this period the Corps of Topographical Engineers had evolved into an agency in support of Manifest Destiny- the manifestation of the American urge to expand the nation's boundaries westward to the Pacific Ocean. It was during this stage of collecting topographic and geographic data in the West that members of the Corps of Topographical Engineers, particularly Fremont, were drawn into the conflict with Mexico.33

That the members of the corps became involved in efforts to expand the nation seemed only natural- their exploration and mapping simply became the byproduct of any new territorial gains. Fremont, one of the more illustrious members of the corps, has been both accused of and credited with being the agent of Manifest Destiny in the seizure of California. Historian William H. Goetzmann, in his seminal work on the topogs' explorations in the West, writes that the corps was a central institution of Manifest Destiny as well as the focus for a national spirit of romanticism. In the drive westward, he states, the corps served as the agent of a democratic collective will.34

By 1845 Manifest Destiny provided the impetus for deploying the Topographical Engineers in areas close to the Mexican border. Three Army expeditions, two composed entirely of topogs, were dispatched westward. Although their chief task directly related to the threat of war, the Army topographers also received instructions to gather scientific information.

On 23 May 1845, Colonel Stephen Watts Kearny's dragoon force of mounted infantrymen set out from Fort Leavenworth, Kansas. The expedition headed south to Bent's Fort (located in southeastern Colorado) and returned to Fort Leavenworth via a route paralleling the Arkansas River. By following this route Kearny's troopers provided some security to the wagon trains traveling between Santa Fe and St. Louis, and the presence of the horse soldiers on the plains also offered some measure of protection to the wagon trains moving along the Oregon Trail. Besides gathering

geographic information of the border regions the reconnaissance succeeded in making a strong show of force and impressed the Indians, deterring them from any outbursts if war did break out with Mexico. In the end, Kearny's military reconnaissance proved the worthiness of American cavalry mobility.35

The Topographical Engineers attached 2d Lt. William B. Franklin to the expedition to record the information gained and to map the region. Franklin arrived at Fort Leavenworth after Kearny's departure, and he joined the column eight days later. The dragoons had headed northwest along the Oregon Trail toward Fort Laramie, then following the North Platte River, they passed Chimney Rock on 10 June. When the expedition arrived at the fort on the 18th, Kearny called for an immediate council with the Sioux Indians. Franklin recorded the colonel's use of pageantry and strength to impress and deter the Indians from attacking the wagon trains along the Oregon Trail. The young topographer observed that during the parley the Indians exhibited feelings of guilt and knew that the arrival of the dragoons meant possible punishment for past misdeeds. Kearny left Fort Laramie with an agreement from the temporarily awed Indians to refrain from attacking the Oregon-bound settlers. The dragoons resumed their march west to South Pass, passing such landmarks as Independence Rock and Red Buttes. After returning to Fort Laramie, the column turned south and arrived at Bent's Fort in late July. The soldiers resumed the march the next day and returned to Fort Leavenworth by 24 August 1845.36

The reconnaissance achieved impressive results. The mobile force marched some 2,200 miles in 99 days, and in his report

Kearny suggested repeating such excursions in lieu of establishing "expensive" forts. His ideas differed quite a bit from those of Fremont and other topographers. The topogs viewed the establishment of forts as an inducement to frontier settlement and protection along key trade and emigration trails.37

Franklin prepared a careful map and report of the route for publication as part of Kearny's report. The printed report included abstracts of the topographer's journal along with those of other officers on the reconnaissance, but they did not provide much new information. The map, however, proved of value since it provided the corps with an exercise in western map-making. In addition, most of Franklin's map incorporated the information Fremont had obtained in his 1843 and 1843-1844 expeditions. In any case, the information gathered on the plains country served as a useful guide to settlers moving westward over the route.38

Much broader in scope were the two topographical expeditions that set forth that year. Both originated from orders issued to Bvt. Captain Fremont- his and an ancillary expedition under 2d Lt. James W. Abert, Colonel Abert's son. In these cases, however, Topographical Engineer officers, not line officers, commanded the expeditions. Besides the military missions assigned to the topographers, the soldier-scientists of the corps also received instructions to gather scientific data on the areas they passed through.

For the most part the topogs moved easily from their role as civil engineers and scientists to their primary duties of map-making, intelligence, and military assignments in support of the Army under wartime conditions. To improve the work of the corps Colonel Abert persistently urged establishing a unit of topographical enlisted men to help in surveys and military duties. Doing so would relieve the corps from detailing soldiers from other branches, particularly from the artillery, and save on the cost of hiring civilians. Congress, how

ever, did not act on this recommendation. The corps, therefore, remained composed entirely of officers, and the topogs continued the practice of contracting with civilians.39

Once his topogs joined a field command Colonel Abert lost direct control over them. At best, Abert could request the commanders to allow his Topographical Engineers to do additional tasks desired by his bureau. From a strictly military standpoint, the topographers assigned to a command became staff officers. During the course of the war nearly half of the members of the corps served under the commands of Generals Stephen W. Kearny, Winfield Scott, Zachary Taylor, and John E. Wool. However, the majority of these topogs kept their technical lines of communication open to the bureau. Throughout the war the topogs in the field consistently submitted letters and copies of reports to Colonel Abert in Washington.40

The United States entered this war like many others, unprepared. Campaign plans did not exist. The small and inexperienced Army needed to be expanded, trained, equipped, and deployed great distances to operate in vast unknown lands. The Army did not have an intelligence system, and an urgent need arose for reliable information on the geography and topography of the envisioned war zone. Commanders appointed to lead campaigns in Texas and Mexico (including the future American Southwest) lacked information on roads, sources of supplies, facilities, obstacles, and even the climate. This ignorance of geography and lack of military intelligence dramatically increased the work of the corps as soon as its members joined their field commands.41

Hartman Bache	Stephen H. Long
James D. Graham	William Turnbull 4

Augustus Canfield	Joseph E. Johnston 4	John McClellan
Thomas J. Cram 4	Thomas J. Lee	Howard Stansbury
Campbell Graham	Thomas B. Linnard 4	William H. Swift
George W. Hughes 4	John Mackay	William G. Williams 1,4

Jacob E. Blake 1,4	Charles N. Hagner 4	James H. Simpson
William H. Emory	Andrew A. Humphreys	Lorenzo Sitgreaves
John C. Fremont 2,4	John N. Macomb	William H. Warner
John W. Gunnison	Eliakim P. Scammon 4	Israel C. Woodruff

James W. Abert 4	William R. Palmer	William F. Smith
Francis T. Bryan 4	William G. Peck 4	George Thom 4
George H. Derby 4	John Pope 4	Joseph D. Webster 4
William B. Franklin 4	William F. Raynolds	Amiel W. Whipple
Edmund L. F. Hardcastle 4	Martin L. Smith 4	Thomas J. Woods 3,4
George Meade 4