The location of New Mexicos west boundary is based on the geographic coordinates of Ship Rock established by the Wheeler survey of 1874. A year later Chandler Robbins, a Deputy Surveyor of the U. S. General Land Office, received a contract to locate and monument Four Corners and to survey and monument the state line to its intersection with the Mexican boundary, for which he was to be paid $70 per mile.
As early as 1854 the New Mexico territorial legislature sent a memorial to Congress asking that the territory be divided. Over the next several years citizens groups and others made various proposals for the creation of a separate territory, mostly along an east-west line, and by the spring of 1860 ten bills for that purpose had been defeated. The 109th meridian as a dividing line apparently was first suggested by the territorial legislature in 1858. Finally, an Act of Congress to separate Arizona from New Mexico was signed into law by President Lincoln on February 24, 1863. In a case of national pride edging out common sense, the dividing line was defined as the 32nd meridian west of Washington, it being as close to the 109th of Greenwich as reference to even degrees of longitude would allow. By law of 1850 the Washington Meridian bisected the dome of the old Naval Observatory in Washington D. C. and eventually defined the boundaries of eleven western states, until the Act was repealed in 1912.
To survey the state line Chandler Robbins was furnished the Greenwich coordinates of the southwest needlepoint of Wilsons Peak, as Ship Rock was called at the time. From it he calculated the position of the 32nd Washington meridian to be eleven miles and 49.39 chains due west. Wilsons Peak could not be occupied and the distance from it was measured by triangulation. Surveying on the meridian some twenty miles due north to intersect the Darling line, Robbins fell one mile and forty-five chains east of the monument that Ehud N. Darling had established in 1868 to mark the intersection of his 37th parallel survey with the 109th meridian. Since the longitude of the Arizona boundary as calculated by Robbins was almost 3 minutes of arc west of the 109th meridian he should have been west of Darlings monument, but later surveys have shown that the error was Darlings.
For this original point of Four Corners Robbins on July 10, 1875 set a shaft of hard sandstone, 7 feet long, 12 inches wide and 6 inches thick; set 3 feet in the ground. Judging the terrain unsuitable for the establishment of an astronomical station, Robbins went 49 chains northeast into the valley of the San Juan River, where he cut a large cottonwood tree to use the stump to support his instrument to make observations for azimuth. Running from Four Corners south on the meridian, at 390 miles and 48.31 chains he intersected the international boundary on October 17th a mile south of Guadalupe Canyon, a point he monumented with a large granite stone.
In a for that period unusual example of civic-mindedness Chandler Robbins wrote a letter to the editor of the Santa Fe Daily New Mexican, where it was published on November 1, 1875. In it, Robbins explained:
For the benefit of your many readers whom I suppose will be interested therein, I herewith send you a brief description of the most prominent points on or near the boundary line between Arizona and New Mexico. It seems to have been the general impression that the line was the 109 of longitude west of Greenwich. Such is not the case, as the law makes it 32 of longitude west from Washington, which corresponds to 109 2 59.25 west from Greenwich, and which places the line a small fraction less than three miles farther west than would have been the case if it had been run as the 109 of longitude Robbins goes on to describe the entire line from Four Corners south, relating it to known geographic features and names of settlers. Monuments have been placed at the crossings of all roads and prominent streams, he wrote, giving their distance from the nearest house or bridge. At the same time he described the location of running streams, soil conditions, and sites where grass or timber was available.
Robbins field notes of his boundary survey in their neat handwriting and descriptive detail stand in stark contrast to the skimpy information contained in Clarks field notes of the Texas boundary survey, even if one considers the fact that Robbins surveyed in a geographically much more interesting and diverse area. Also, in contrast to the Clark survey, Robbins was required to monument the mileposts. Unlike the Texas and Colorado boundaries of New Mexico, Robbins survey has never been challenged in court. Beginning about 1890 and continuing throughout the 20th century it was retraced by GLO and BLM surveyors as a part of township subdivisions, dependent resurveys, and Indian boundary surveys, so that today most if not all of the original monuments have been replaced with brass-caps. The original of his notes, in eight leather-bound field books, along with his topographic plats and vertical profiles of the state line, are in the archives of the New Mexico State Library in Santa Fe.
Robbins southwest corner of New Mexico was remonumented with a cast iron pyramid by the international boundary survey of 1892/93 and is designated Monument 71.
As a supplement I will pass on what I was able to dig up about Chandler Robbins, the man. He was a native of Springfield, Ohio, where he was born in February 1844 the son of the Principal of a boarding school. His father, the Rev. Chandler Robbins, was an educator of some renown and it can be assumed that under his tutelage Chandler jr. received a good education. He may have studied civil engineering; his notes and plats on record in Santa Fe bear all the marks of a concientious and accomplished professional. During the Civil War he enlisted in 1862 as a sergeant with the 86th Ohio Infantry. He served in various units until 1866 when he was honorably discharged with the brevet rank of captain. He was in Louisiana at that time and rented a plantation, but when his crops were destroyed in a flood he returned to Springfield. In 1873 Robbins came to New Mexico to work under Surveyor General James K. Proudfit. As an applicant for the state-line job he was highly recommended to the Commissioner of the General Land Office by a number of influential persons who judged him competent, deserving and a good Republican . Prior to commencing that survey he obtained a $5,000 life insurance policy from a company in Newark, N.J. That company was very jittery about insuring surveyors in far away New Mexico Territory and amended the policy with a clause: It is understood and agreed that the Company is not to be liable if death should occur from hostile Indians.
After another contract to survey the boundaries of an enlargement of the Colorado River Indian Reservation in Arizona that netted him $6,000, Robbins returned to Ohio. In 1877 he married and was elected Clark County Surveyor, an office he resigned in 1878 when with a partner he purchased a small gray-iron foundry, renaming it Robbins & Myers. The company is still in business with corporate headquarters in Dayton and has grown into a large international manufacturer of equipment to handle industrial fluids. Later he was an officer in a Chicago sewing machine factory that turned to manufacture bicycles and relocated to New York City. At the turn of the century Chandler Robbins retired to a farm in Ohios Scioto Marches, successfully raising onions and two sons (a third one had died in infancy). Chandler Robbins died on the 18th of August 1921.