An Early Exponent of the Volcanic Origin of the Giant's Causeway
"Here, hapless Hamilton, lamented name!
To fire volcanic traced the curious frame,
And, as his soul, by sportive fancy's aid,
Up to the fount of time's long current strayed,
Far round these rocks he saw fierce craters boil,
And torrent lavas flood the riven soil:
Saw vanquished Ocean from his bounds retire,
And hailed the wonders of creative Fire."
Drummond.
These lines are taken from a poem, "The Giant's Causeway," written in 1811, when the nature of the basaltic rocks was regarded as doubtful, and many held that their origin was to be traced to the action of water rather than fire. Hamilton is rightly brought forward as a champion of the volcanic theory. In his "Letters concerning the Northern Coast of Antrim," published towards the close of the eighteenth century, he adduces strong reasons to show that the Giant's Causeway is no isolated freak of Nature, but part of a vast lava field which covered Antrim and extended far beyond the Scottish islands. Nor does he confine his attention to geology, but fulfils the promise on the title page, giving an account of the antiquities, manners, and customs of the country. To those who care to read of this part of the world before the days of railroads and electric tramways, when Portrush was a small fishing village, and the lough which divides Antrim from Down bore the name of the ancient city of Carrickfergus, this old volume will possess many attractions. Three copies lie before me; two belong to editions published in the author's lifetime; the third was printed in Belfast in 1822, and contains a short memoir and a portrait of Dr. Hamilton. The latter is taken from one of those black silhouettes by which, before the art of photography was known, our grandfathers strove to preserve an image of those they loved. In this imperfect likeness we can see below the wig a massive forehead, and features which betoken no small determination of character. We can well believe that we are gazing on the face of a scholar, a man of science, a divine, of one who believed that death, even in the tragic form in which it came to him, was but the laying aside of a perishable machine, the casting away of an instrument no longer able to perform its functions.
William Hamilton was born in December, 1757, in Londonderry, where the family had resided for nearly a century, his grandfather having been one of the defenders of the city during the famous siege. Little is known of his boyhood. Before he was fifteen he entered the University of Dublin, and after a distinguished career obtained a fellowship in 1779. It was while continuing his theological and literary studies that his attention was drawn to the new sciences of chemistry and mineralogy. We can imagine the ardent student attracting around him a band of kindred spirits, who, meeting on one evening of the week under the name of Palæosophers, studied the Bible and ancient writings bearing on its interpretation, and the next, calling themselves Neosophers, discussed the phenomena of Nature, and the discoveries of Cavendish, or the views of Buffon and Descartes. Nor did his marriage in 1780 to Sarah Walker interrupt these pursuits.
Hamilton was one of the founders of the Royal Irish Academy, and dedicated his "Letters concerning the Coast of Antrim" to the Earl of Charlemont, the first president of that body. The book opens with an account of his visit to the Island of Raghery or Rathlin, where he was charmed with the primitive manners of the people and the friendly relations existing between them and their landlord. He examined the white cliffs, the dark basaltic columns, and the ruins of the old castle, where Robert Bruce is said to have made a gallant defence against his enemies. Here he found cinders embedded in the mortar, showing that the lime used in building the walls had been burnt with coal. This is adduced as a proof that the coal-beds near Fair Head had been known at an early period, possibly at a time anterior to the Danish incursions of the ninth and tenth centuries—a view confirmed by the discovery of an ancient gallery extending many hundred yards underground, and in which the remains of the tools and baskets of the prehistoric miners were found.
In a later letter a history is given of the Giant's Causeway, and of the various opinions which have been held regarding its origin. Beginning with the old tradition[110] that the stones had been cut and placed in position by the giant, Fin McCool or Fingal, when constructing a mighty mole to unite Ireland to Scotland, Hamilton alludes to the crude notions exhibited in some papers published in the early Transactions of the Royal Society. He criticizes severely "A True Prospect of the Giant's Causeway," printed in 1696 for the Dublin Society, showing how the imagination of the artist had planted luxuriant forest-trees on the wild bay of Port Noffer, and transformed basaltic rocks into comfortable dwelling-houses. The two beautiful paintings made by Mrs. Susanna Drury in 1740 are referred to in very different language, and anyone who has seen engravings of these will endorse his opinion, and feel that this lady has depicted, with almost photographic accuracy, the Causeway and the successive galleries of basaltic columns, which lend a weird and peculiar grandeur to the headlands of Bengore.
A large portion of Hamilton's work is occupied with a minute investigation of these headlands, and of the lofty promontory of Fair Head. A description is given of the jointed columns of the Causeway, whose surface presents a regular and compact pavement of polygon stones; we are told that this basaltic rock contains metallic iron, and that he has himself observed how, in the semicircular Bay of Bengore, the compass deviates greatly from its meridian, and each pillar or fragment of a pillar acts as a natural magnet. He also points out that columnar rocks are found in many parts of Antrim, and traces the basaltic plateau from the shores of Lough Foyle to the valley of the Lagan; nay more, he bids us extend our gaze, and remember "that whatever be the reasonings that fairly apply to the formation of the basaltes in our island, the same must be extended with little interruption over the mainland and western isles of Scotland, even to the frozen island of Iceland, where basaltic pillars are to be found in abundance, and where the flames of Hecla still continue to blaze."[111]
Hamilton argues, in opposition to the views of many of his contemporaries, that the vicinity of the Giant's Causeway to the sea has nothing whatever to do with the peculiar structure of its jointed columns, which he ascribes to their having been formed by the crystallization of a molten mass. The following are his words:
"Since, therefore, the basaltes and its attendant fossils[112] bear strong marks of the effects of fire, it does not seem unlikely that its pillars may have been formed by a process, exactly analogous to what is commonly denominated crystallization by fusion.... For though during the moments of an eruption nothing but a wasteful scene of tumult and disorder be presented to our view, yet, when the fury of those flames and vapours, which have been struggling for a passage, has abated, everything then returns to its original state of rest; and those various melted substances, which, but just before, were in the wildest state of chaos, will now subside and cool with a degree of regularity utterly unattainable in our laboratories."[113]
It is true that modern geologists would not apply the term "crystallization" to the process by which the basaltic columns have been formed, but all would agree that they have assumed their peculiar shape during the slow cooling of the molten lava of which they consist; thus Professor James Thomson[114] states that the division into prisms has arisen "by splitting, through shrinkage, of a very homogeneous mass in cooling."