although the extremities might be one hundred miles apart. Then it is necessary to make the triangulation all over the kingdom consistent with itself—that is to say, that the sum of the three angles in every triangle should be 180 degrees, and the sum of all the angles round every station 360 degrees. Three unknown quantities in an equation is generally considered a near enough approximation to the truth. The intrepid calculators of the Ordnance Survey face the solution of equation with thirty-six unknown quantities.

The principal triangulation of the kingdom commenced, as we have seen, by Roy in 1784, was carried on at intervals till 1858, when it may be said to have been practically completed. This survey was extended to Scotland in 1809, and continued with several breaks till 1823, when it was suspended for fifteen years. The survey is now finished, and maps on the 6-inch scale have been published of the whole country, and for the most part also on the 25-inch scale. The useful 1-inch map is far advanced in two styles-contours only, and hills. Nearly all towns and populous places have been issued on the 5-feet or 10-feet scale. Regarding the battle of the "Scales," fought in the House of Commons for over twelve years-1851-63-with a pertinacity hardly surpassed by the battle of the "Guns," it is neither seasonable nor necessary to enlarge on now or here. Nor can further room be occupied by any description of the delicate processes employed before maps can be submitted to the public for acceptance in all their beautiful and accurate details. To the present Director of the survey, Sir Henry James, R.E., belongs the high honour-first, of connecting the triangulation of the United Kingdom with France and Belgium; second, calling in the aid of, and almost inventing, the art, known as Photozincography, by which the maps, with all their delicate outlines, are transferred through a simple method to such a permanent surface as has given us the best copies yet produced of many precious ancient records-DomesdayBook, Saxon Charters, and the most suggestive "National State Papers," illustrating the history of England, Scotland, and Ireland.

Mention has been made of the remarkable care taken to preserve General

Roy's wonderful Theodolite. With another of his survey inventions Fortune was less favourable; his Standard Yard, used for measuring the Hounslow base line, and afterwards placed in Exchequer Chambers, Westminster, being burnt in the great fire which in October, 1834, consumed the Houses of Parliament. In this case a Royal Commission on Weights and Measures had luckily provided some years earlier that, if the General's standard measure was lost, it would be lawful to renew it by means of the length of the seconds pendulum. General Roy's death was of startling suddenness. Having prepared for the Royal Society, by command of the King, an elaborate series of papers concerning the exact latitude of Greenwich and Paris Observatories, he was revising the printed sheets at home after a day's work in the office, June 30, 1790, when he was seized with an illness of which he died in two hours. Besides being a Major-General, at this time the great military engineer was Deputy Quartermaster-General, Colonel of the 30th Foot, Surveyor-General of Coasts and Batteries, and a Fellow of the Royal Society, as well as of the Society of Antiquaries. In 1793 the latter learned body issued the General's "Military Antiquities" as a posthumous volume, folio, profusely illustrated with drawings. One year after his measurement of the Hounslow line a paper on the subject, contributed to "Transactions of the Royal Society," secured to Roy the Copley gold medal. The most eminent mathematicians of his day-Ivory and Leslie among the rest-did not fail to do justice to his great merits, nothing more censorious being written of him than that he had somehow failed to appreciate to its full extent a theorem first propounded by his friend Adrian Legendre, the theorem being to the effect that, if each of the angles of a small spherical triangle be diminished by one-third of the spherical excess, the sines of the angles thus diminished will be very nearly proportional to the length of the sides themselves; so that the computations with respect to such spherical triangles may be made by the rules of plane trigonometry. Aided by this theorem, drawn from the newer mathematics, it was thought that General Roy might have simplified many of his calculations, and in the case of a few-only a very few-been more exact than he arrived at by the old system of calculation.

Still, it was universally admitted that General Roy possessed a strong and vigorous understanding; was an excellent draughtsman, and a profound natural philosopher, as was abundantly established in his paper on the measurement of heights by the barometer, printed in the "Philosophical Transactions," 1777. Nor was it judged to be less to the General's credit that he pursued his abstruse studies at a time when the British army afforded few instances of the kind either to encourage him by example or rouse him by emulation, and when the connection between mathematical science and his military art was but imperfectly understood.

BURNS AND "HIGHLAND MARY.”

BURNS incense is now offered up with such profusion each January as to make the poet's joke about his own reputation rather a matter of history than prophecy. Writing to his friend, Gavin Hamilton, on the occasion of the first Edinburgh visit, he remarks "I am in a fair way of becoming as eminent as Thomas à Kempis or John Bunyan, and you may expect henceforth to see my birth-day inserted among the wonderful events in the Poor Robin's and Aberdeen Almanacs along with the Black Monday and the Battle of Bothwell Bridge." Popularity naturally incites inquiry, and many occurrences turn up for discussion which in lesser or more obscure reputations would be allowed to pass unnoticed. One of the unconscious services rendered by the warm admirers of Burns is the inquiry they compel into facts and surmises associated with his life, and so establishing more or less of what is clearly historic, The poet's connection with "Highland Mary" has long had an interest of this kind for plodding inquirers-an interest in no degree lessened, but rather strengthened, by a mystery Burns has himself thrown around the story, quite out of keeping with his usual candour in such affairs. The attachment has been described as the purest and most elevated ever formed by the poet, and the songs in praise

of the simple Highland girl are justly ranked among the most finished efforts of his muse. The "banks and braes and streams around the Castle o' Montgomery" has become classic ground to thousands who never heard of the wooded slopes of Parnassus; Doon has been found more inspiring than Castaly; and to the Coilsfield dairymaid has been vouchsafed an immortality rivalling the Laura of Petrarch or the Beatrice of Dante. On her merits and her fame public opinion has long since set its seal. It is so far as the subject touches the poet that it has an interest for inquirers. Recent research would almost lead to the conclusion that the "Highland Mary" attachment, instead of being a thing standing apart in the poet's life as a permanent or earnest feeling, was but an episode in a wider domestic drama-only an accidentalmost the accident of an accident. Burns may be permitted in the first instance to tell the story in his own way. In the course of a few notes on some of the Scottish songs printed in the "Museum," prepared for his neighbour the Laird of Friars' Carse some time after 1788-probably about 1794-the poet writes of the "Highland Lassie" as "a composition of mine in very early life before I was at all known to the world. My Highland lassie was a warm-hearted, charming young creature as ever blest a man with generous love. After a pretty long tract of the most ardent reciprocal attachment we met by appointment on the second Sunday of May in a sequestered spot on the banks of Ayr, where we spent the day in taking a farewell before she should embark for the West Highlands to arrange matters among her friends for our projected change of life. At the close of autumn she crossed the sea to met me at Greenock, where she had scarce landed when she was seized with a malignant fever before I could even hear of her illness." In a similar strain the poet writes to Thomson in 1792, enclosing the song "Will you go to the Indies, my Mary?" "In my very early years, when I was thinking of going to the West Indies, I took the following farewell of a dear girl." It is now necessary to set down a few dates, in order to avoid being misled by the poet's phrases about "very early life," and "very early years." It is known to all acquainted in even a slight degree

with the life of Burns, that the West Indies project occupied his mind only once, and that was in the summer of 1786, when the Kilmarnock edition of his poems was passing through the press, and when--and this bears closer on the inquiry-when Jean Armour's father was threatening the hapless bard with the terrors of a jail in order to compel him to provide for his illegitimate offspring. Burns at this time could hardly be described as very young. He had quite completed twenty-seven on his last birth-day-not an early age in affairs of gallantry for him who, at seventeen, addressed "Handsome Nell" to his girl neighbour in the harvest field. If the surmise is correct, and no other theory fits in so well, or fits in at all, with ascertained facts, the romantic parting on the banks of Ayr took place in the summer of 1786-"the second Sunday in May" being the 14th of the month. But the surprise does not end here. Some months before this Burns had placed in the hand of his friend Aiken an irregular but legal certificate of marriage with Jean Armour; nor, as appears from one of the poet's own letters, was it destroyed till some day between the 3rd and 17th of the preceding April. What the poet calls the "pretty long tract of ardent reciprocal attachment" comes, therefore, within thirty days of being inconveniently near formal obligations to his earlier love. Destroyed though the declaration was, Burns was none the less bound by its contents-a responsibility he appears to have overlooked or been misinformed about when he presented Mary Campbell with the famous Bible that summer afternoon. In one of the volumes may yet be seen in the poet's handwriting, "And ye shall not swear by my name falsely-I am the Lord" (Levit. xvi. 12); in the other, "Thou shalt not forswear thyself, but shalt perform unto the Lord thine oath" (St. Matt. v. 33). According to Dr. R. Chambers, sound lawyers have already given it as their opinion that the destruction of the informal declaration in no way altered the relative position of the parties, but only introduced an element of difficulty, had it been necessary to establish the marriage by evidence in Court. The verbal testimony of any who had seen or even heard of the document would have gone far to fix the conditions it was originally