Part 32 (2/2)

The first part of the semicircle includes the pa.s.sage from infancy to boyhood and manhood. While that period lasts, time seems to pa.s.s very slowly. We long to be men, and doing men's work. What I have called The Tableland of Life is then reached. Ordinary observation shows that between thirty and fifty the full strength of body and mind is reached; and at that period we energise our faculties to the utmost.

[Image] The Dial of Life

Those who are blessed with good health and a sound const.i.tution may prolong the period of energy to sixty or even seventy; but Nature's laws must be obeyed, and the period of decline begins, and goes on with accelerated rapidity. Then comes Old Age; and as we descend the semicircle towards eighty, we find that the remnant of life becomes vague and cloudy. By shading off, as I have done, the portion of the area of the diagram according to the individual age, every one may see how much of life is consumed, and what is left--D.V.. Here is my brief record:

AGE YEAR.

-- 1808. BORN 19TH AUGUST.

9 1817. WENT TO THE HIGH SCHOOL, EDINBURGH.

13 1821. ATTENDED THE SCHOOL OF ARTS.

21 1829. WENT TO LONDON, TO MAUDSLAY'S.

23 1831. RETURNED TO EDINBURGH, TO MAKE MY ENGINEERS' TOOLS.

26 1834. WENT TO MANCHESTER, TO BEGIN BUSINESS.

28 1836. REMOVED TO PATRICROFT, AND BUILT THE BRIDGEWATER FOUNDRY.

31 1839. INVENTED THE STEAM HAMMER.

32 1840. MARRIAGE.

34 1842. FIRST VISIT TO FRANCE AND ITALY.

35 1843. VISIT TO ST. PETERSBURG, STOCKHOLM, DANNEMORA.

37 1845. APPLICATION OF THE STEAM HAMMER TO PILE-DRIVING.

48 1856. RETIRED FROM BUSINESS, TO ENJOY THE REST OF MY LIFE IN THE ACTIVE PURSUIT OF MY MOST FAVOURITE OCCUPATIONS.

I have not in this list referred to my investigations in connection with astronomy. All this will be found referred to in the text.

It only remains for me to say that I append a resume of my inventions, contrivances, and workshop ”dodges,” to give the reader a summary idea of the Active Life of a working mechanic. And with this I end my tale.

CHRONOLOGICAL LIST OF MECHANICAL INVENTIONS AND TECHNICAL CONTRIVANCES.

by James Nasmyth.

1825. A mode of applying Steam Power for the Traction of Ca.n.a.l Barges, without injury to the Ca.n.a.l Banks.

A Ca.n.a.l having been formed to connect Edinburgh with the Forth and Clyde Ca.n.a.l, and so to give a direct waterway communication between Edinburgh and Glasgow, I heard much talk about the desirableness of subst.i.tuting Steam for Horse power as the means of moving the boats and barges along the ca.n.a.l. But, as the action of paddle wheels had been found destructive to the ca.n.a.l banks, no scheme of that nature could be entertained. Although a tyro in such matters, I made an attempt to solve the problem, and accordingly prepared drawings, with a description of my design, for employing Steam power as the tractive agency for trains of ca.n.a.l barges, in such a manner as to obviate all risk of injury to the banks.

[Image]

The scheme consisted in laying a chain along the bottom of the ca.n.a.l, and of pa.s.sing any part of its length between three grooved and notched pulleys or rollers, made to revolve with suitable velocity by means of a small steam-engine placed in a tug-boat, to the stern of which a train of barges was attached.*

[footnote...

Had this simple means of ”tugging” vessels through water-ways been employed in our late attempts to ascend the rapids of the Nile, some very important results might have issued from its adoption.

The steam-engine could thus warp its way along the chain, taking it up between the rollers of the bow of the tug-boat, and dropping it into the water at the stern, so as to leave the chain at the service of the next following tug-boat with its attached train of barges. By this simple mode of employing the power of a steam-engine for ca.n.a.l boat traction, all risk of injury to the banks would be avoided, as the chain and not the water of the ca.n.a.l was the fulcrum or resistance which the steam-engine on the tug-boat operated upon in thus warping its way along the chain; and thus effectually, without slip or other waste of power, dragging along the train of barges attached to the stern of the steam-tug. I had arranged for two separate chains, so as to allow trains of barges to be conveyed along the ca.n.a.l in opposite directions, without interfering with each other.

I submitted a complete set of drawings, and a full description of my design in all its details, to the directors of the Ca.n.a.l Company; and I received a complimentary acknowledgment of them in writing. But such was the prejudice that existed, in consequence of the injury to the ca.n.a.l banks resulting from the use of paddle Wheels, that it extended to the use of steam power in any form, as a subst.i.tute for ordinary horse traction; and although I had taken every care to point out the essential difference of my system (as above indicated) by which all such objections were obviated, my design was at length courteously declined, and the old system of horse traction continued.

In 1845 I had the pleasure to see this simple mode of moving vessels along a definite course in most successful action at the ferry across the Hamoaze at Devonport, in which my system of employing the power of a steam-engine on board the ferry boat, to warp its way along a submerged chain lying along the bottom of the channel from side to side of the ferry, was most ably carried out by my late excellent friend, James Rendell, Esq., C.E., and is still, I believe, in daily action, giving every satisfaction.

1826. An Instrument for Measuring the Total and Comparative Expansion of all Solid Bodies.

My kind friend and patron, Professor Leslie, being engaged in some investigations in which it was essential to know the exact comparative total expansion in bulk of metals and other solid bodies, under the same number of degrees of heat, mentioned the subject in the course of conversation. The instrument at that time in use was defective in principle as well as in construction, and the results of its application were untrustworthy. As the Professor had done me the honour to request me to a.s.sist him in his experiments, I had the happiness to suggest an arrangement of apparatus which I thought might obviate the sources of error; and, with his approval, I proceeded to put it in operation.

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