Part 27 (1/2)

We returned to the city in time to be present at a most interesting lecture by Hugh Miller on the Boulder Clay.

He ill.u.s.trated it by some scratched boulders which he had collected in the neighbourhood of Edinburgh. He brought the subject before his audience in his own clear and admirable viva voce style.

The Duke of Argyll was in the chair, and a very animated discussion took place on this novel and difficult subject.

It was humorously brought to a conclusion by the Rev. Dr. Fleming, a shrewd and learned geologist. Like many others, he had encountered great difficulties in arriving at definite conclusions on this mysterious subject. He concluded his remarks upon it by describing the influence it had in preventing his sleeping at night.

He was so restless on one occasion that his wife became seriously alarmed.

”What's the matter wi' ye, John? are ye ill?” ”On no,” replied the doctor, ”it's only that confounded Bounder Clay!” This domestic anecdote brought down the house, and the meeting terminated in a loud and hearty laugh.

I, too, contributed my little quota of information to the members of the British a.s.sociation. I had brought with me from Lancas.h.i.+re a considerable number of my large graphic ill.u.s.trations of the details of the Moon's surface. I gave a viva voce account of my lunar researches at a crowded meeting of the Physical Section A. The novel and interesting subject appeared to give so much satisfaction to the audience that the Council of the a.s.sociation requested me to repeat the account at one of the special evenings, when the members of all the various sections were generally present. It was quite a new thing for me to appear as a public lecturer; but I consented. The large hall of the a.s.sembly Rooms in George Street was crowded with an attentive audience. The Duke of Argyll was in the chair. It is a difficult thing to give a public lecture especially to a scientific audience.

To see a large number of faces turned up, waiting for the words of the lecturer, is a somewhat appalling sight. But the novelty of the subject and the graphic ill.u.s.trations helped me very much. I was quite full of the Moon. The words came almost unsought; and I believe the lecture went off very well, and terminated with ”great applause.”

And thus the meeting of the British a.s.sociation at Edinburgh came to an end.

This, however, was not the end of our visit to Scotland.

I was strongly urged by the Duke of Argyll to pay him a visit at his castle at Inverary. I had frequently before had the happiness of meeting the Duke and d.u.c.h.ess at the Earl of Ellesmere's mansion at Worsley Hall He had made us promise that if we ever came to Scotland we were not to fail to pay him a visit. It was accordingly arranged at Edinburgh that we should carry out our promise, and spend some days with him at Inverary before our return home. We were most cordially welcomed at the castle, and enjoyed our visit exceedingly. We had the pleasure of seeing the splendid scenery of the Western Highlands the mountains round the head of Loch Fyne, Loch Awe, and the magnificent h.o.a.ry-headed Ben Cruachan, requiring a base of more than twenty miles to support him,--besides the beautiful and majestic scenery of the neighbourhood.

But my chief interest was in the specimens of high geological interest which the Duke showed me. He had discovered them in the Island of Mull, in a bed of clay shale, under a volcanic basaltic cliff over eighty feet high, facing the Atlantic Ocean. He found in this bed many beautifully perfect impressions of forest tree leaves, chiefly of the plane-tree cla.s.s. They appeared to have been enveloped in the muddy bottom of a lake, which had been sealed up by the belching forth from the bowels of the earth of molten volcanic basaltic lava, and which indeed formed the chief material of the Island of Mull. This basaltic cliff now fronts the Atlantic, and resists its waves like a rock of iron. To see all the delicate veins and stalklets, and exact forms of what had once been the green fresh foliage of a remotely primeval forest, thus brought to light again, as preserved in their clay envelope, after they had lain for ages and ages under what must have been the molten outburst of some tremendous volcanic discharge, and which now formed the rock-bound coast of Mull, filled one's mind with an idea of the inconceivable length of time that must have pa.s.sed since the production of these Wonderful geological phenomena.

I felt all the more special interest in these specimens, as I had many years before, on my return visit from Londonderry, availed myself of the nearness of the Giant's Causeway to make a careful examination of the marvellous volcanic columns in that neighbourhood. Having scrambled up to a great height, I found a thick band of hemat.i.tic clay underneath the upper bed of basalt, which was about sixty feet thick. In this clay I detected a rich deposit of completely charred branches of what had once been a forest tree. The bed had been burst through by the outburst of molten basalt, and converted the branches into charcoal.

I dug out some of the specimens, and afterwards distributed them amongst my geological friends. The Duke was interested by my account, which so clearly confirmed his own discovery. On a subsequent occasion I revisited the Giant's Causeway in company with my dear wife.

I again scrambled up to the hemat.i.tic bed of clay under the basaltic cliff, and dug out a sufficient quant.i.ty of the charred branches, which I sent to the Duke, in confirmation of his theory as to the origin of the leaf-beds at Mull.*

[footnote...

I received the following reply from the Duke of Argyll dated ”Inverary, Nov. 19, 1850”: --

”MY DEAR SIR--Am I right in concluding, from the description which; you were so kind as to send to me, that the lignite bed, with its superinc.u.mbent basalts, lies above those particular columnar basalts which form the far-famed Giant's Causeway? I see from your sketch that basalts of great thickness, and in some views beautifully columnar, do underlie the lignite bed; but I am not quite sure that these columnar basalts are those precisely which are called the Causeway.

I had never heard before that the Giant's Causeway rested on chalk, which all the basalts in your sketch do.

[Image] The Astrologers Tower--A Day Dream. By James Nasmyth.

(Facsimile.)

”I have been showing your drawing of 'Udolpho Castle' and 'The Astrologer's Tower' to the d.u.c.h.ess of Sutherland, who is enchanted with the beauty of the architectural details, and wishes she had seen them before Dunrobin was finished; for hints might have been taken from bits of your work. --Very truly yours,

ARGYLL.”

In the year following the meeting of the British a.s.sociation at Edinburgh, the great Exhibition of all nations at London took place.

The Commissioners appointed for carrying out this n.o.ble enterprise had made special visits to Manchester and the surrounding manufacturing districts for the purpose of organising local committees, so that the machinery and productions of each might be adequately represented in the World's Great Industrial Exhibition. The Commissioners were met with enthusiasm; and nearly every manufacturer was found ready to display the results of his industry. The local engineers and tool-makers were put upon their mettle, and each endeavoured to do his best. Like others, our firm contributed specimens of our special machine tools, and a fair average specimen of the steam hammer, with a 30 cwt.

hammer-block.

I also sent one of my very simple and compact steam-engines, in the design of which I had embodied the form of my steam hammer--placing the crank where the anvil of the hammer usually stands. The simplicity and grace of this arrangement of the steam-engine were much admired.

Its merits were acknowledged in a way most gratifying to me, by its rapid adoption by engineers of every cla.s.s, especially by marine engineers. It has been adopted for driving the shafts of screw-propelled steams.h.i.+ps of the largest kind. The comparatively small s.p.a.ce it occupies, its compactness, its get-at-ability of parts, and the action of gravity on the piston, which, working vertically, and having no undue action in causing wearing of the cylinder on one side (which was the case with horizontal engines), has now brought my Steam Hammer Engine into almost universal use*

[footnote...

Sir John Anderson, in his Report on the machine tools, textile, and other machinery exhibited at Vienna in 1873, makes the following observations: --”Perhaps the finest pair of marine engines yet produced by France, or any other country, were those exhibited by Schneider and Company, the leading firm in France. These engines were not large, but were perfect in many respects; yet comparatively few of those who were struck with admiration seemed to know that the original of this style of construction came from the same mind as the Steam Hammer.

Nasmyth's Infant Hercules was the forerunner of all the steam hammer engines that have yet been made from that type, which is now being so extensively employed for working the screw propeller of steam vessels.”

The Commissioners, acting on the special recommendation of the jury, awarded me a medal for the construction of this form of steam-engine*

[footnote...

The Council of the Exhibition thus describe the engine in the awards: -- ”Nasmyth, J., Patricroft, Manchester, a small portable direct-acting steam-engine. The cylinder is fixed, vertical and inverted, the crank being placed beneath it, and the piston working downwards.

The sides of the frame which support the cylinder serve as guides, and the bearings of the crank-shaft and fly-wheel are firmly fixed in the bed-plate of the engine. The arrangement is compact and economical, and the workmans.h.i.+p practically good and durable.”