Map of a Nation by Rachel Hewitt Read Free Book Online

expressed every bend, corner, and irregular turn in the several hedges; all rivers, bridges, highways, gates, and stiles’. Other manuals to the landsteward’s role emphasised that ‘it is not only necessary that a Steward should be a good Accomptant, but also that he should have a tolerable Degree of Skill in Mathematicks , Surveying, Mechanicks, and Architecture’.

    5. Alidades.
     
    Although little documentation has survived from John Roy’s employment at Hallcraig and Milton, the estate maps on which he relied were almost certainly constructed with two instruments, called a ‘plane table’ and an ‘alidade’. An alidade was a mechanism that allowed an object to be brought within a straight line of eyesight, and developed from the historical astronomical instrument known as the astrolabe, which was used to determine latitude. Deriving from an Arabic word meaning ‘ruler’, early alidades consisted of two vanes, each of which contained a thin hole or slot (without lenses) which was placed at either end of a small bar. A plane table comprised a level surface mounted on a robust base, and it had been used in surveying since the sixteenth century, perhaps even earlier, and generally with an alidade. We can imagine William’s father teaching the young boy to make a map of his employer’s estate using these two instruments. John Roy would have first measured a small baseline in a field on the Hallcraig estate, a straight, flat distance whose length depended on the size of the land to be surveyed. He drew this base on a sheet of paper that was fastened onto the surface of the plane table, and positioned the table directly over one end of the actual baseline so that it was in perfect alignment with the marking ofthat same spot on the paper. Crouching down, and bringing his eye to the level of the table, John showed William how one of the alidade’s vanes should be placed at the mark indicating the end of the base. He then looked along its length, gently shifting the instrument’s position until a landmark on the estate, such as a fountain, was brought into view through both vanes. John now traced onto the paper the straight line of eyesight that passed from the mark of the baseline’s end, along the length of the alidade, to this landmark. Then he moved his plane table to the other end of the baseline, again perfectly aligning the actual spot with that drawn on the paper. John Roy now traced a line from this end of the baseline to the fountain in the same way as before. Two lines were thus etched onto the embryonic map, radiating out from either end of the baseline to the fountain. The spot where these lines intersected produced the position of the landmark for the map. John showed William how this technique could be replicated over and over again, until an outline of the complex landscape of the estate was plotted onto paper by means of the simplest form of geometry.
    It is likely that William Roy was proficient from a young age in the skills of estate surveying and plane-tabling, and it seems that he demonstrated a remarkable early aptitude for map-making. But records regarding the young boy’s formal education are inconclusive: Roy was educated at the nearby grammar school in Lanark, but accounts of his teenage years are silent. It has been suggested that he worked for the Post Office, that he was employed in road-building, or that he was trained by the Army’s Board of Ordnance, but Roy’s name does not crop up on any of those institutions’ records in this period. When the Jacobite Rebellion broke out in 1745, he was nineteen years old. The Upper Ward of Lanarkshire erupted into frenzied activity to halt the progress of the Jacobites as they retreated from Derby back to the Highlands. Initially the Young Pretender’s army intended to march straight through the Ward, as it was ‘the only communication that is open, from the north to England’, as one of the Roys’ neighbours explained. Around 700 local