In 1864, after graduating eighth in a class of 27 from West Point, William H. Ludlow went south as chief engineer of the newly formed XX Corps of the Army of the Cumberland.  He saw action in the Atlanta campaign, on Sherman's march to the sea, and in the Carolinas during the closing weeks of the war.  Within less than a year, Ludlow had advanced from brevet captain to brevet lieutenant colonel for his distinguished service.

In late 1865 Ludlow began his first assignment at Jefferson Barracks, Missouri, where he organized and took command of the Engineer Depot and Company E of the Engineer battalion, a company of Topographical Engineers.  On this assignment Ludlow learned firsthand the topographical needs of commanders who were fighting hostile Indians in unmapped territory.  With a commission as captain of engineers, Ludlow returned east in March, 1867.  As assistant to General Quincy A. Gillmore until November 1872, he worked on coastal fortifications and civil works projects on Staten Island and at Charleston, South Carolina.  In 1872 Ludlow traveled to St. Paul, Minnesota, to become chief engineer in the Department of the Dakota and portions of Montana and Wyoming.

When Ludlow arrived at department headquarters, he found a challenging task before him.  The Army was attempting to maintain order and protect American citizens as the Sioux Indians responded with increasing hostility to the white man's incursions into their territory.  The Northern Pacific Railroad was pushing its lines deeper into Montana territory.  Settlers and fortune hunters flooded the region to exploit the new opportunities for trade and the abundant game population and to search for gold.  Little regard was given to Indian land rights supposedly secured by treaty in 1868.  Anticipating more difficult times, including full-scale war, the Army needed maps of the territory, descriptions of its topography, and recommendations on sites for new forts.  Knowledge of sources for wood, water, and grass was particularly important to the cavalry on campaign


Custer with the first grizzly he killed. Identified from left, are: Indian Scout Bloody Knife, Lieutenant Colonel George A. Custer, Private Noonan, and Engineer Captain William H. Ludlow.


During his four years in the Department of the Dakota, Ludlow made two major expeditions.  On the first in July and August 1874, he accompanied Lieutenant Colonel George Armstrong Custer, commander of the 7th Cavalry and a friend from West Point days, into the Black Hills, home of the Sioux.  The region was believed to be rich in gold.  Custer's assignment was to obtain military information.  The mere presence of a military force was enough to stir up Indian resentment.  The inclusion of gold hunters in the reconnaissance party and Custer's haughty attitude made matters worst.

The Black Hills expedition was an eye opener for Ludlow.  In his report on the trip, he evidenced a marked sympathy for Indian treaty rights and disdain for those who sought to exploit the region.  Believing that the reports of gold in the hills were highly exaggerated, Ludlow thought it folly to allow prospectors to flood the area when increased tensions would certainly result.  The Indians would never allow white men to occupy their territory.  Were they to do so, he wrote, "settlements there could only be protected by force and the presence of a considerable military power.

Custer differed sharply.  He found the discoveries of gold "exceedingly promising" and urged further investigation.  As for the rights of settlers, he stated bluntly: "The title of the Indian should be extinguished as soon as practical."  And why not, he argued, since his expedition revealed that the Indians actually occupied only a small portion of the hills?  Ludlow's advice counted for little in the climate of gold fever and land hunger.

Accompanying Captain Ludlow in the engineer detachment was Sergeant Charles Becker, a solemn old German soldier who rode a two-wheeled odometer cart to measure the miles.  On a terrible July day two years later, he would have the sad duty of riding the jouncy cart about the battlefield at the Little Big Horn, charting on paper the last hours of General Custer's command during the investigation of that disaster.  Now he was simply charting his way to the Black Hills, and this assignment made him a much-sought-after man.  The first question the soldiers asked when camp was made:  How many miles today?  If Becker's horse had not run away during the march and fouled up his calculations, he could give the answer to the last tenth of a mile.

Following a different trail, but roughly paralleling the route of Sergeant Becker, was another engineer in an ambulance also carrying odometers.  An odometer was an instrument in a stout leather case, strapped to the wheel of a cart to measure the revolutions.  At night the readings of the instruments were averaged and converted to miles.  If the route had been level, no correction factor was applied; if the country had been rough the reading was reduced from 1 to 3 per cent.


Typical odometer cart, circa 1872.  The instrument is visible just above the hub of the wheel.


Becker and another sergeant carried prismatic compasses and kept a full record of compass readings.  When these distances and directions were committed to paper, the result was a "meander line," the simplest kind of mapping technique.  When checked against astronomical observations for latitude and longitude, and augmented by barometric readings for altitude, these calculations became the raw material for the maps that Becker would draw when he got back to the drafting room in Department headquarters in St. Paul.

Each sergeant had an assistant to help with compass readings.  A fifth man carried two chronometers in a basket to minimize jarring, and the sixth member of the detachment was equipped with a thermometer and aneroid barometer.  Besides these enlisted soldiers there was a civilian topographer, W. H. Wood, who helped Colonel Ludlow with transit and sextant reading during the day, and made night observations whenever practical.

Obviously, Colonel Ludlow was not conducting a sophisticated topographic survey; he knew that his work must be done over by men with more time and better equipment.  He was meticulous, however.  The position of most of the camps he determined astronomically.  Now that he was in rougher country, where points of reference were available, he was doing some triangulation - checking points in the hills from a measured base by means of trigonometry.  But mathematics and the tricky workings of the aneroid barometer would lead him astray at least once.  He would record the altitude of Harney's Peak as 9,700 feet, a mark some 2,500 feet higher than later measurements.

The records of Ludlow's observations are still on file, with a manuscript copy of his final report, in the National Archives.  He made his calculations on printed forms, ruled off with thin red and blue lines and bearing such headings as "Determination of the Latitude by the Observed Double Altitudes of Polaris off the Meridian."

Although he was not considered a fighting soldier, and was classed with the bug hunters by the troops, Ludlow had the respect of the line officers.  He was, as Samuel Barrows said, "an officer who was not afraid of getting sunburnt."  He had known Barrows and most of the Seventh Cavalry officers since the Yellowstone expedition, when he had surveyed the Yellowstone River from its mouth at Fort Buford to a point ten miles above the Powder River.

Ludlow was thirty-one, the son of a distinguished Civil War general William Handy Ludlow.  He was a West Pointer, class of  '64, and as chief engineer of the XX Corps he had been breveted three times for gallantry during the war.  A long career lay ahead.  Eventually he would command a brigade in the Spanish-American War and serve for a time as military governor of Havana. 


Paul K. Walker, Introduction to Exploring Nature's Sanctuary: Captain William Ludlow's Report of a Reconnaissance from Carroll, Montana Territory, on the Upper Missouri to the Yellowstone National Park, and Return Made in the Summer of 1875, (U.S. Government Printing Office, 1876).

Donald Jackson, Custer's Gold, The United States Cavalry Expedition of 1874, (University of Nebraska Press, 1966).