Lovers of Longfellow will recall the poet’s song to the lighthouse, but how many of his admirers know to what beacon these stirring lines refer? When they were penned the author had in his mind’s eye an example of the engineer’s handiwork which ranks as one of the finest sea-rock lights in existence, worthy of comparison with the most famous of similar structures scattered throughout the waters washing the Old World.

This is the far-famed Minot’s Ledge light, warning the seafarer making to and from Boston Bay of the terrible peril which lurks beneath the waves on the southern side of the entrance to this busy indentation. “Like the great giant Christopher it stands,” a powerful monument to engineering genius, dogged perseverance against overwhelming odds, and a grim, bitter contest lasting five weary years between the implacable elements and human endeavour. The Minot Ledge is one of those jagged reefs which thrust themselves far out into the sea, studded with pinnacles and chisel-like edges, which never, or very seldom, protrude above the waves. Ship after ship fouled this danger spot, either to be sunk or to be so badly crippled that it barely could contrive to crawl to safety.

The prosperity of Boston was threatened by this peril to shipping, and therefore it is not surprising that a resolution was passed to devise some ways and means of indicating its presence to those who go down to the sea in ships. The solution was offered in a skeleton structure fashioned from iron, which was designed by Captain W.H. Swift, of the United States Topographical Engineers. He searched the reef through and through to ascertain the point where the beacon should be placed so as to prove of the greatest value. This in itself was no simple matter, inasmuch as Minot’s Ledge is but one of a great area of wicked crags, which collectively are known as the Cohasset Rocks, and which straggle over the sea-bed in all directions. After the position had been reconnoitred thoroughly, and sounding and levels had been taken, the engineer decided that the most seaward rock of the group, known as the Outer Minot, would be the most strategical position, and accordingly he planned to erect his beacon thereon.

It was a daring proposal, because the reef at the point selected only exposes some 25 feet of its mass above the falling tide, and then the highest point of the rock scarcely thrusts itself 3½ feet into the air. It was realized that the periods of working between the tides would inevitably be very brief, while even then, owing to the open position of the ridge, a landing would only be possible in very smooth weather, and the men would have to suffer exposure to the fury of the waves as they dashed over the ledge.

Captain Swift decided upon a skeleton iron structure, not only because it would be quicker to erect and would cost less, but because it would offer the least resistance to the waves, which would be free to expend their energy among the stilts. The task was taken in hand at the first favourable opportunity, and, the system lending itself to rapid construction, marked progress was made every time the workmen succeeded in getting on the ledge. The lantern and keepers’ quarters were supported upon nine piles, 60 feet above the rock. The legs were so disposed that eight described the circumference of a circle, while the ninth constituted the axis.

This tower was completed in 1848, and for the first time the navigator making these treacherous waters received a powerful warning to keep clear of Minot’s Ledge. For three years the beacon survived the battering of wind and wave, but its welcome beam was last seen on the night of April 16, 1851. In the spring of that year a gale of terrific fury beat upon the Massachusetts coast. The wind freshened on April 13; the next day it rose to its full force, and did not abate for four days. The good people of Boston grew apprehensive concerning the plight of the two keepers of the lonely Minot’s light, but, however willing they might have been to have put out to the beacon, they were absolutely impotent before the ferocity of the elements. Time after time the light vanished from sight as it was enveloped in an angry curling mountain of water. On April 17 the doleful tolling of the lighthouse bell was heard, but the light was never seen again. The structure had slipped completely from sight, together with its faithful keepers, swallowed by the hungry Atlantic. Evidently the wail of the bell was a last plea for assistance, because no doubt the lighthouse had bowed to the storm and was tottering when the tolling rang out. But the call brought no help; it was the funeral knell of the guardians of the beacon. When the sea went down a boat pushed off to the ledge, and all that was seen were a few bent piles. Captain Swift had done his work well. The waves could not tear his beacon up by the roots, so had snapped off the piles like carrots, and had carried away the lantern.

This sensational disaster, after a brief existence of three years, did not augur well for the permanence of a light upon this precarious ledge. The Outer Minot appeared to be determined to continue its plunder of ships, cargoes, and lives, untrammelled. Accordingly, for three years no effort was made to bring about its subjugation.

In 1855 General Barnard, one of the most illustrious engineers which the United States has ever produced, brought forward the plans for a structure which he thought would resist the most formidable attacks of wind and wave. He took Rudyerd’s famous Eddystone tower as his pattern. This was perhaps the strongest design that could be carried out against the sea, having one weak point only—it was built of wood. General Barnard contemplated a similar structure for Minot’s Ledge, but in masonry.

The Lighthouse Board, which had recently been inaugurated to control the lighthouses around the coasts of the country, examined the idea minutely, and submitted the design to the most expert criticism and discussion, but all were so impressed with its outstanding features that they decided to support it whole-heartedly. A minute survey of the rock was prepared, and the plans were straight away perfected for the preparation of the masonry on shore. So carefully was this work carried out, that, with the exception of a few blocks of masonry constituting the foundations, which had to be prepared on the site, and some slight variations in the method of construction, the original ideas were fulfilled.

Work was commenced in 1855, the building operations being placed in the hands of B.S. Alexander, at that time Lieutenant of Engineers, and the successful completion of the work was due in a very great measure to his ability and ingenuity, because the whole undertaking was placed in his hands and he had to overcome difficulties at every turn as they arose.

The builder was handicapped in every way. First there was the brief period in which operations could be carried out upon the site, the working season extending only from April 1 to September 15 in each year. This is not to say that the masons were able to toil upon the rock continuously every day during this interval—far from it. In order to get the foundations laid there were three essentials—a perfectly smooth sea, a dead calm, and low spring-tides. Needless to say, it was on very rare occasions indeed that these three requirements were in harmony. As a matter of fact, they could occur only about six times during every lunar month—three times during full moon, and three at the change. Even then, either the wind or the sea intervened to nullify the benefits arising from the lowest tides. So much so that, although work commenced at daybreak on Sunday, July 1, 1855, only 130 working hours were possible upon the rock before labours ceased for the season in the middle of the following September.

On gaining the rock, Lieutenant Alexander decided to make use of the holes which had been driven into the granitic mass by Captain Swift to receive the piles of the previous structure. The twisted and broken pieces of iron were withdrawn and the holes cleaned out. Simultaneously the upper surface of the rock was pared and trimmed by the aid of chisels, which was no easy task, because at times the masons were compelled to manipulate their tools as best they could in two or three feet of water. This preparation of the rock to receive the base constituted one of the most notable features of the work. In the greater number of other outstanding achievements upon sea-rocks the surface of the latter has been above the waves at lowest spring-tides, whereas in this case a great part of the foundation work was continuously submerged.

This preparation of the rock-face necessitated the final trimming and shaping upon the site of many of the masonry blocks forming the root of the tower. They could not possibly be prepared ashore to bring about the tight fit which was imperative. Accordingly, all but the bottom faces of the blocks were prepared in the depot on the mainland, and they were then shipped to the ledge for final paring and trimming.

The attachment of the bottom courses to the rock-face was carried out very ingeniously. Bags of sand were brought on to the rock and laid around the spot upon which a particular block of stone was to be laid. The sacks, being filled with sand, were pliable, so that, when deposited, they adapted themselves to the contour of the ledge, and prevented the water making its way in under the rampart. The water within this small dam was then removed, sponges being used in the final emptying task, so as to suck out the salt sea from the cracks and crevices, leaving the surface on which the block of stone was to be laid quite dry. A film of cement was then trowelled upon the rock surface, and upon this was laid a sheet of muslin. The inclusion of the muslin was a wise precaution, because while the work was in progress a wandering wave was liable to curl over the rock, swamping the small dried space, when, but for the presence of the muslin, the cement would have been carried away. At the same time the cement was able to penetrate the meshes of the muslin when the stone was deposited, so as to grip the surface of the latter and to hold it tightly in position.

Under such abnormal conditions of working the masons had many exciting moments. No matter how smooth was the sea, several renegade waves would plunge over the ledge. The masons had to be prepared for these unwelcome visitors, and precautions had to be introduced to prevent them being washed off their slender foothold. A substantial iron staging was erected over the working area on the rock, to facilitate the handling of the building material. A number of ropes were attached to this staging, the free ends of which dangled beside the workmen. These were the life-lines, one being provided for each man. A lookout was posted, who, when he saw a wave approaching and bent upon sweeping the rock, gave a shrill signal. Instantly each workman dropped his tools, clutched his life-line tightly, threw himself prostrate on the rock, and allowed the wave to pass over him. The situation certainly was uncomfortable, and the men often toiled in soddened clothes, but an involuntary bath was preferable to the loss of a life or to broken limbs.

Work advanced so slowly that during the first two years, which were devoted to the excavation of the pit and the preparations of the rock-face, only 287 hours’ work were accomplished. In the third year this task was completed, and four stones laid in a further 130 hours 21 minutes. By the end of the working season of 1859 twenty-six courses were finished, so that, while the volume of work fulfilled in 1,102 hours 21 minutes, and spread over five years, certainly was not imposing, it was remarkable under the circumstances.

The stones for the foundations were sent from shore with the indication -3’ 5”, -2’ 9”, -1’ 3”, and so on, indicating that these stones were prepared for positions 3 feet 5 inches, 2 feet 9 inches, and so on, below zero. And the zero mark was 21 inches below water! Above the zero mark the stones were prefixed by a “plus” sign. The shaft is purely conical, and solid except for a central well extending from the foundations up to the level of the entrance. The successive courses of stones were secured to one another, and each stone was attached to its neighbour in the ring by the aid of heavy iron dogs, so that the lower part of the shaft forms a practically solid homogenous mass. What are known as continuous “dowels” were sunk through each course of masonry into the holes in the solid rock prepared by Captain Swift for his skeleton light, this further attachment of the mass to the ledge being continued until the twelfth course was gained. Thus additional security is obtained by anchoring the tower firmly to the reef.

The solid portion of the building is 40 feet in height from the level of the first complete ring of stones, and the tower is 80 feet high to the lantern gallery. The over-all height to the top of the lantern cupola is 102¾ feet, while the focal plane is 84½ feet above mean high-water. The first stone was laid on July 9, 1857, while the masons completed their duties on June 29, 1860, so that five years were occupied upon the work. In erection 3,514 tons of rough and 2,367 tons of hammered stone, in addition to 1,079 numbered stones, were used, and the total cost, including the light-keepers’ houses on the mainland, was £60,000, or $300,000, so that it ranks among the more costly lights which have been provided for the seafarer’s benefit.

On November 15, 1860, nine and a half years after the destruction of the first beacon, the light was once more thrown from Minot’s Ledge for the benefit of passing ships. The light is of the second order, visible fourteen and three-quarter miles out to sea, and is of the flashing type, signalling “143” every thirty seconds thus—one flash followed by three seconds’ darkness, four flashes with three seconds’ eclipse, and three flashes with an interval of fifteen seconds’ darkness.

The tower has been subjected to repeated prodigious assaults, the north-east gales in particular thundering upon this reef with tremendous fury, but it has withstood all attacks with complete success.