an autobiography-第11节
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aspect； however crowded its walls and shelves might be。 Everything was in its place； and there was a place for everything。 It was in this workroom that I first began to handle mechanical tools。 It was my primary technical schoolthe very foreground of my life。
＇Image＇ Bow…and…string Roofs and Bridges
I may mention one or two of my father's mechanical efforts； or rather his inventions in applied science。 One of the most important was the 〃bow…and…string bridge；〃 as he first called it； to which he early directed his attention。 He invented this important method of construction about the year 1794。 The first bow…and…string bridge was erected in the island of St。 Helena over a deep ravine。
Many considered； from its apparent slightness； that it was not fitted to sustain any considerable load。 A remarkable and convincing proof was； however； given of its stability by the passage over it of a herd of wild oxen； that rushed across without the slightest damage to its structure。 After so severe a test it was for many succeeding years employed as a most valuable addition to the accessibility of an important portion of the island。 The bow…and…string bridge has since been largely employed in spanning wide spaces over which suburban and other railways pass； and in roofing over such stations as those at Birmingham； Charing Cross； and other Great Metropolitan centres； as well as in bow…and…string bridges over rivers。 I give the fac…simile of his original drawings* ＇footnote。。。 The original drawings of these bow…and…string bridges； of various spans； are now deposited at the Gallery of the Museum of Naval Architecture at South Kensington； and are signed 〃Alexander Nasmyth 1796。〃 。。。＇ for the purpose of showing our great railway engineers the originator of the graceful and economical method of spanning wide spaces； now practised in every part of the civilised world。
Another of his inventions was the method of riveting by compression instead of by blows of the hammer。 It originated in a slight circumstance。 One wet； wintry Sunday morning he went into his workroom。 There were some slight mechanical repairs to be performed upon a beautiful little stove of his own construction。 To repair it； iron rivets were necessary to make it serviceable。 But as the hammering of the hot rivets would annoy his neighbours by the unwelcome sound of the hammer； he solved the difficulty by using the jaws of his bench vice to squeeze in the hot rivets when put into their places。 The stove was thus quickly repaired in the most perfect silence。
This was； perhaps； the first occasion on which a squeeze or compressive action was substituted for the percussive action of the hammer； in closing red…hot rivets； for combining together pieces of stout sheet or plate iron。 This system of riveting was long afterwards patented by Smith of Deanston in combination with William Fairbairn of Manchester； and it was employed in riveting the plates used in the construction of the bridges over the River Conway and the Menai Straits。
It is also universally used in boiler and girder making； and in all other wrought…iron structures in which thorough sound riveting is absolutely essential； and by the employment of hydraulic power in a portable form a considerable portion of iron shipbuilding is effected by the silent squeeze system in place of hammers； much to the advantage of the soundness of the work。 My father frequently； in aftertimes； practised this mode of riveting by compression in place of using the blow of a hammer； and in remembrance of the special circumstances under which he contrived this silent and most effective method of riveting； he named it 〃The Sunday Rivet。〃
CHAPTER 3。 An Artist's Family。
Although Alexander Nasmyth had to a considerable extent lost his aristocratic connection as a portrait painter； yet many kind and generous friends gathered round him。 During his sojourn in Italy； in 1783； he had the good fortune to make the acquaintance of Sir James Hall of Dunglass； Haddingtonshire。 The acquaintance afterwards ripened into a deeply…rooted friendship。
During the winter season Sir James resided with his family in his town house in George Street。 He was passionately attached to the pursuit of art and science。 He practised the art of painting in my father's room； and was greatly helped by him in the requisite manipulative skill。 Sir James was at that time engaged in writing his well…known essay 〃On the Origin of Gothic Architecture；〃 and in this my father was of important use to him。 He executed the greater number of the illustrations for this beautiful work。 The book when published had a considerable influence in restoring the taste of architects to a style which they had heretofore either neglected or degraded。
Besides his enthusiasm in art and architecture； Sir James devoted a great deal of time to the study of geology。 The science was then in its infancy。 Being an acute observer； Hall's attention was first attracted to the subject by the singular geological features of the sea…coast near his mansion at Dunglass。 The neighbourhood of Edinburgh also excited his interest。 The upheaval of the rocks by volcanic heat as seen in the Castle Hill； the Calton Hill； and Arthur's Seat formed in a great measure the foundation of the picturesque beauty of the city。 Those were the days of the Wernerian and Huttonian controversy as to the origin of the changes on the surface of the earth。 Sir James Ball was President of the Edinburgh Royal Society； and necessarily took an anxious interest in the discussions。 He observed and experimented； and established the true volcanic nature of the composition and formation of the rocks and mountains which surround Edinburgh。
I have been led to speak of this subject； because when a boy I was often present at the discussions of these great principles。 My father； Sir James Hall； Professors Playfair and Leslie； took their accustomed walks round Edinburgh； and I clung eagerly to their words。 Though unable to understand everything that was said； these walks had a great influence upon my education。 Indeed； what education can compare with that of listening attentively to the conversation and interchange of thought of men of the highest intelligence？ It is on such occasions that ideas； not mere words； take hold of the memory； and abide there until the close of life。
Besides mixing in the society of scientific men； my father enjoyed a friendly intercourse with the artists of his day。 He was often able to give substantial help and assistance to young students； and he was most liberal in giving them valuable practical instruction； and in assisting them over the manipulative difficulties which lay in their way。 He was especially assiduous when he saw them inspired by the true spirit of art； and full of application and industry；without which nothing can be accomplished。 Amongst these young men were David Wilkie； Francis Grant； David Roberts； Clarkson Stanfield； William Allan； Andrew Geddes； 〃Grecian〃 Williams； Lizars the engraver； and the Rev。 John Thomson of Duddingston。
Henry Raeburn was one of his most intimate friends and companions。 He considered Raeburn's broad and masterly style of portrait painting as an era in Scottish art。 Raeburn； with innate tact； discerned the character of his sitters； and he imparted so much of their individuality into his portraits as to make them admirable likenesses in the highest sense。 In connection with Raeburn； I may mention that when he was knighted by George IV。 in 1822； my father； who was then at the head of his profession in Scotland； was appointed chairman at the dinner held to do honour to the great Scottish portrait painter。
Raeburn often joined my father in his afternoon walks round Edinburgh a relaxation so very desirable after hours of close attention to artistic work。 They took delight in the wonderful variety of picturesque scenery by which the city is surrounded。 The walks about Arthur's Seat were the most enjoyable of all。 When a boy I had often the pleasure of accompanying them； and of listening to their conversation。 I thus picked up many an idea that served me well in after life。 Indeed； I may say； after a long experience； that there is no class of men whose company I more delight in than that of artists。 Their innate and highly…cultivated power of observation； not only as regards the ever…varying aspects of nature； but also as regards the quaint； droll； and humorous varieties of character； concur in rendering their conversation most delightful。 I look back on these walks as among the brightest points in my existence。 I have been led to digress on this subject。 Although more correctly belonging to my father's life； yet it is so amalgamated with my own that it almost forms part of it； and it is difficult for me to separate the one from the other。
And then there were the pleasant evenings at home。 When the day's work was over； friends looked in to have a fireside cracksometimes scientific men； sometimes artists； often both。 They were all made welcome。 There was no formality about their visits。 Had they been formal； there would have been comparatively little pleasure。 The visitor came in with his 〃Good e'en〃； and seated himself
