Preparing for a Mission
Erskine was born in Dunferm, Scotland, the son of a minister, and received his elementary education at the Dunfermline Grammar School. In 1748 he enrolled at the University of Edinburgh. Lack of funds and the need to earn a living forced him to interrupt his studies, and it was not until 1752 that he was able to resume his studies. Soon thereafter he again left college and went to London and engaged in business. The treachery of his partner left him heavily in debt and he was declared bankrupt. His excellent character and sincerity of purpose kept him out of debtors' jail. He engaged in further study in the field of hydraulic engineering and invented various hydraulic appliances, including a centrifugal hydraulic engine which became a competitor of the chain pump. As a result of his success he was elected a fellow of the Royal Society in 1771, and among the signers of his certificate was Benjamin Franklin. He was able to gradually pay off his indebtedness.

In 1770 he had been asked to go to America to represent a group of British capitalists who had invested in an iron company with extensive mines in upper New Jersey. He had prepared himself for his mission by spending several months making a survey of iron mining in Great Britain. He arrived in New York with his wife in June 1771 and established himself at Ringwood, New Jersey. Erskine took up residence at the old manor house, where he lived for two years. He entered upon his duties, striving desperately to revive the foundry which had been almost destroyed by the previous manager, finally succeeding in restoring it to a dividend paying basis. Erskine had proven himself to be thoroughly devoted to the interests of his employers, but the British owners had meanwhile lost courage in the endeavor and offered the property for sale. There were no purchasers, however, so Erskine was forced to carry on.

During the next several years he became actively sympathetic to the cause of the American colonists. In 1775 he organized the men in his employ into a military company and their services were offered to the Provincial Congress. Erskine was commissioned a captain in the Bergen County militia and his men were exempted from compulsory military service in any other company. The furnace proved to be a valuable resource for cannon shot and other war materials when the war began. Erskine urged the Continental Congress and General George Washington himself to exempt his men from field duty so that the iron works could be continued without interruption.

Erskine constructed a chevaux de frise to be suspended across the Hudson River at Fort Washington to prevent British ships from passing, but because it was never carried entirely across the river, it was not successful. At the furnace was also produced the large iron chain that was placed across the river at West Point. After the Continental troops had been driven out of New Jersey in 1776, the British made occasional raids against the iron mines and the Ringwood Manor, but they were repulsed.

Surveyors Wanted
Among the Continental Army's most urgent needs for the prosecution of the war, in addition to military engineers, were cartographers and surveyors capable of making maps and charts required for military maneuvers. In a letter to the Continental Congress addressed to John Hancock, General Washington wrote: "The want of accurate maps of the country which has been hitherto the scene of war has been of great disadvantage to me. I have in vain endeavoured to procure them, and have been obliged to make shift with such sketches as I could trace out from my own observation and that of gentlemen around me . . . I really think if Gentlemen of known Character and probity could be employed in making Maps (from actual Survey) of Roads, Rivers, Bridges and Fords over them, the mountains and passes through them, it would be of the Greatest Advantage."

It was during this time in July 1777 that General Washington met Erskine for the first time while at his camp at Pompton, New Jersey, where he had been quartered in July 11-13 due to inclement weather. He learned that Erskine was a capable civil engineer and well acquainted with the region west of the Hudson, and offered him the position of Geographer and Surveyor-General of the Continental Army. Washington addressed a letter to the members of a committee of the Continental Congress in which he wrote to the Committee of the Congress to remind them of his needs. "A good Geographer to Survey the Roads and take Sketches of the Country where the Army is to be would be extremely useful and might be attended with extremely valuable consequences," he wrote. "He might with propriety have the chief direction of the Guides who must have a head to procure, govern, and pay them. If such a person should be approved of I would beg leave to recommend Mr. Rob.t Erskine who is thoroughly skilled in this business, has already assisted us in making maps of the country, and has (as I am informed), uniformly supported the Character of a fast friend of America."

A resolution was passed by Congress the following week stating: "That General Washington be empowered to appoint Mr. Robert Erskine, or any other person that he may think proper, geographer and surveyors of the roads, to take sketches of the country, the seat of war, and to have the procuring, governing and paying the guides employed under him."

Difficulties Encountered
Erskine was commissioned Geographer and Surveyor-General of the Continental Army on July 27th. Losing no time, on the following day Washington informed Erskine of the committee's confirmation and at the same time notified his young aide, Alexander Hamilton. Erskine thereafter had the double duty of having to produce maps for the Army while maintaining the operation of the iron works for military purposes. Washington was a frequent visitor at Ringwood on his many trips to and from West Point.

Erskine immediately set to work, assembling a small staff of assistants, using anyone who was available. The first project was the preparation of a series of operational maps of the region upon which he depicted the physical characteristics of the country from the Hudson Highland to Philadelphia, with special emphasis on upper New Jersey westerly to Ringwood, and from Jersey City to Cornwall. Erskine described the difficulties he encountered in the work in a letter to Washington written shortly after his appointment. "In planning a country a great part of the ground must be walked over," he wrote, "particularly the Banks of Rivers and Roads: as much of which may be traced and laid down in three hours as could be walked over in one; or in other words, a Surveyor who can walk 15 miles a day may plan 5 miles . . . Six attendants to each surveyor will be proper; to wit, two chain-bearers, one to carry the instrument, and three to hold flagstaffs . . . Young gentlemen of Mathematical Genius, who are acquainted with the principles of Geometry, and who have the taste for drawing would be most proper assistants for a Geographer."

(To be continued in the next issue)

Erskine gradually assembled a corps of more than twenty surveyors, in addition to an adequate complement of chain-bearers and other assistants. It was a herculean task because many of the men skilled in the art had been drafted or were assigned to other priorities. Erskine and his staff issued more than 130 different maps between the time of his appointment and his death three years later. For the most part, the maps were first sketched upon a plane table in a roughly finished form. They delineated the roads and primary topographical features as well as commanding elevations and identification points such as churches and taverns. Although crudely executed, the maps proved to be surprisingly accurate. They were subsequently contracted in size in a new compilation produced at a reduced scale, plotted on a grid of conic projection based on the prime meridian of New York City, taken from its City Hall.

The work of the surveyors was extremely hazardous, for not only were they subjected to the dangers of inclement weather and wildlife, but they faced danger from the enemy as well. General Washington was alert to these problems, and provided such assistance of which he was capable. While Erskine's staff was mapping the Hudson Highlands, for example, Washington directed General James Clinton to move towards the enemy lines in the direction of Kings Bridge "to cover the Engineers and Surveyors, while they reconnoiter . . ."

Despite the growing success of Erskine's operation, it did not totally resolve the cartographic problems of the Continental Army. Multiple copies of the maps were needed for the prosecution of the war and had to be distributed to staff officers and others. The small field sketches produced by the cartographers or surveyors were supplemented with notes compiled hurriedly in the field, which generally incorporated many abbreviations liable to misinterpretation. These were submitted to professionally trained draftsmen who assembled the individual sketches and rendered them into the required composite form, then delineated a final map supplemented with the information provided in the field notes. Each of the products was an individual project and resulted in a single document. From this final map, individual copies had to be made painstakingly by hand in sufficient numbers to supply the staff. Inasmuch as they had to be kept out of enemy hands, only the officers of the highest rank received copies. Duplicating methods that became popular after the turn of the nineteenth century were not yet developed, and in this time of war there was no capability for engraving and printing of the maps. A manuscript list in Erskine's hand summarizing his maps, totaling 129, is preserved in The New-York Historical Society, together with the major portion of the maps themselves.

On September 18, 1780, while engaged in making some surveys of the Hudson Highlands, Erskine caught a severe cold and sore throat which produced a fever and within two weeks brought about his death on October 2, 1780. That same day Major John Andre was executed as a British spy about twenty miles away at Tappan. Erskine's coffin plate was produced by his assistant and devoted friend Simeon De Witt, and contained the following inscribed in gilt letters:

In memory of
ROBERT ERSKINE, F.R.S.
Geographer and Surveyor General to the Army
of the
United States of America.
Born Sept. 7, 1735. Died Octover 2nd, 1789.
Aged 45 years and 25 days.

Erskine was buried at his home at Ringwood, his resting place marked with a brick table tomb topped with a marble slab, said to have been caused to be erected by General Washington. The same words inscribed on his coffin plate comprise the epitaph upon the marble slab, with an additional sentence:

Son of the Rev. Ralph Erskine, late minister at
Dunfermline in Scotland.

Despite the importance of Erskine's contributions to the success of the American Revolution, relatively little effort has been made to organize his papers, and record his life and work. There has been but one biography which was poorly done, Robert Erskine, The Forgotten General by Albert H. Heusser, published in 1928 by Rutgers University Press. In 1966 the work was edited and many errors corrected by Hubert G. Schmidt in a revised edition titled George Washington's Map Maker. A Biography of Robert Erskine.

The New Jersey Gazette of October 18, 1780 memorialized Erskine as: ". . . a man in whom were united the Christian and the gentleman. His integrity and unbounded benevolence have rendered his death a loss to the publick, and a subject of sincere regret to all his acquaintances. He made the laws of justice the invariable rule of his conduct, and upon this principle espoused the cause of America, in which he served his country with approbation and universal esteem."