"The lighthouse on the Isle of May is situate at the entrance of the Firth of Forth, in North lat. 56° 12´, and long. 2° 36´ west of London. From the lighthouse Fifeness bears by compass N. by E. 1/2 E., distant five miles; and the Staples Rocks, lying off Dunbar, S. by W. 1/2 W., distant ten miles. The light, being formerly from coal, exposed to the weather in an open grate or choffer, was discontinued on the night of the 1st of February, 1816, when a light from oil, with reflectors, known to mariners as a Stationary Light, was exhibited. The new lighthouse tower upon the Isle of May is contiguous to the side of the old one, and is elevated 240 feet above the medium level of the sea, of which the masonry forms 57 feet, and is therefore similar to the old tower in point of height. The new light is defended from the weather in a glazed light-room, and has a uniform steady appearance, resembling a star of the first magnitude, and is seen from all points of the compass, at the distance of about 7 leagues, and intermediately, according to the state of the atmosphere."
In the summer of 1814, shortly after the May had been acquired by the Northern Lights Board, Sir Walter Scott accompanied the Commissioners on their visit of inspection. In the Diary which he kept during the cruise, the following entry occurs under date of the 29th of July, the day on which the lighthouse yacht sailed from Leith:—"Reached the Isle of May in the evening, went ashore, and saw the light—an old tower, and much in the form of a border-keep, with a beacon-grate on the top. It is to be abolished for an oil revolving-light, the grate-fire only being ignited upon the leeward side when the wind is very high.... The isle had once a cell or two upon it. The vestiges of the chapel are still visible. Mr. Stevenson proposed demolishing the old tower, and I recommended 'ruining' it 'à la picturesque', i.e., demolishing it partially. The island might make a delightful residence for bathers."[229] Scott's romantic suggestion was not, however, adopted. The old lighthouse tower on the Isle of May was reduced in height to about 20 feet, and by direction of the Board was converted into a guardroom for the convenience of pilots and fishermen. The square, battlemented, white building is still standing at the present day. Above the door there is a tablet with a figure of the rising sun over the date 1636. It is surmounted by a lion holding an escutcheon, on which the armorial bearings—probably those of the builder—are no longer decipherable. In the vaulted room within the tower there is an old iron grate with the initials A. C., which suit Alexander Cunningham, and are doubtless his.
The ruins mentioned by Sir Walter are also visible at the present day, though in an even more dilapidated state than when he saw them. They are situated in a hollow, towards the south-east end of the island, probably near the spot where the monastery stood. They are doubtless the remains of St. Adrian's Chapel, which continued to be visited by pilgrims long after the destruction of the monastery itself. The space within the walls measures about 32 feet in length and 15 feet in breadth. In the west wall are two windows, of which the semi-circular interior openings seem to indicate Norman work, and suggest the thirteenth century as the date of the building. There are also remnants of windows both in the south and in the north wall. A shapeless gap near the southern extremity shows the position of the door. Just within it there may still be seen what is perhaps a fragment of the holy-water stoup. From the fact that the ruins lie north and south, it has been thought that the chapel occupied only a part of the building, and duly lay east and west within it. If such were the case, it must have been of exceptionally small dimensions, and have contained a very diminutive altar. At the present time no attempt seems to be made to prevent the venerable relic from falling further into decay; and the rough enclosure within which it stands is used as a sheep-pen.
The lighthouse now on the May is situated close to the old tower. It is a massive quadrangular stone building surmounted by a square tower which at a distance gives it the appearance of a church. It first came into use on the 1st of December, 1886. For fifteen years previously the Commissioners of the Northern Lights had been anxious to establish an electric light on the Scottish coast; but it was not till 1883 that the Board of Trade was able to sanction the expenditure, and suggested its introduction at the Isle of May, on the ground that "there was no more important station on the Scottish shores, whether considered as a landfall, as a light for the guidance of the extensive or important trade of the neighbouring coast, or as a light to lead into the refuge of the Forth". The new buildings, engines, electric machines and lamps cost £15,835; but, including old material which it was found possible to utilize, the total installation was estimated at £22,435. As to technical details, it may suffice to mention that the generators are two of De Meritens's alternate-current magneto-electric machines, weighing about four and a half tons each. The engines are a pair of horizontal surface-condensing steam engines, each with two cylinders 9 inches in diameter and 18 inches stroke, making 140 revolutions per minute. There are two steam boilers, of which only one is in use at a time. Each of them is 20 feet long and 5 feet 6 inches in diameter. Only one of the three electric lamps is used at a time, and is changed once an hour to allow it to cool. The light is about 25,000 candle-power, but when seen from the water gives a flash equal to 3,000,000 candles, which can be increased to 6,000,000. The May apparatus is so designed as to give a group of four flashes in quick succession, followed by an interval of darkness lasting thirty seconds. The highest recorded distance at which the reflection of the light has been observed is 61 nautical miles. The May is also provided with a powerful horn, of which the sound serves as a guide during the frequent "haars" or sea-fogs that rise from the North Sea. In addition to this, it has a smaller fixed light which serves as a leading light for ships coming down from Fifeness. It is visible on one side of the island only.
Owing to the increased cost of maintenance of the May light—it is estimated at more than £1000 a year—an Order in Council was issued in 1886, authorizing the collection of two-sixteenths of a penny per ton, as light dues, from vessels carrying cargo or passengers, which may pass or derive benefit from the light when on a coasting or home-trade voyage, and of one penny per ton when on an oversea voyage, subject to the usual deductions.
The May light is served by seven keepers, the chief of whom does not, however, share the watches. Their quarters, which are neat and commodious, and sufficiently large for the accommodation of such of them as have families, are situated at some distance from the lighthouse, between two hills that afford protection from the prevalent gales. Close to them is the engine-house, with its tall chimney-stalk. The necessary supply of water for it is drawn from the little lake, of which early descriptions of the island make mention, and which has now been turned into a reservoir.