an autobiography-第25节
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entleman who took a fancy for the model when he came to purchase some of my father's works。
The price I charged for my models was #10； and with the pecuniary results I made over one…third to my father； as a sort of help to remunerate him for my 〃keep；〃 and with the rest I purchased tickets of admission to certain classes in the University。 I attended the Chemistry course under Dr。 Hope； the Geometry and Mathematical course under Professor Wallace； and the Natural Philosophy course under my valued friend and patron Professor Leslie。 What with my attendance upon the classes； and my workshop and drawing occupations； my time did not hang at all heavy on my hands。
I got up early in the mornings to work at my father's lathe； and I sat up late at night to do the brass castings in my bedroom。 Some of this； however； I did during the day…time； when not attending the University classes。 The way in which I converted my bedroom into a brass foundry was as follows： I took up the carpet so that there might be nothing but the bare boards to be injured by the heat。 My furnace in the grate was made of four plates of stout sheet…iron； lined with fire…brick； corner to corner。 To get the requisite sharp draught I bricked up with single bricks the front of the fireplace； leaving a hole at the back of the furnace for the short pipe just to fit into。 The fuel was generally gas coke and cinders saved from the kitchen。 The heat I raised was superba white heat； sufficient to melt in a crucible six or eight pounds of brass。
Then I had a box of moulding sand； where the moulds were gently rammed in around the pattern previous to the casting。 But how did I get my brass？ All the old brassworks in my father's workshop drawers and boxes were laid under contribution。 This brass being for the most part soft and yellow； I made it extra hard by the addition of a due proportion of tin。 It was then capable of retaining a fine edge。 When I had exhausted the stock of old brass； I had to buy old copper； or new； in the form of ingot or tile copper； and when melted I added to it one…eighth of its weight of pure tin； which yielded the strongest alloy of the two metals。 When cast into any required form this was a treat to work； so sound and close was the grain； and so durable in resisting wear and tear。 This is the true bronze or gun metal。
When melted； the liquid brass was let into the openings； until the whole of the moulds were filled。 After the metal cooled it was taken out； and when the room was sorted up no one could have known that my foundry operations had been carried on in my bedroom。 My brass foundry was right over my father's bedroom。 He had forbidden me to work late at night； as I did occasionally on the sly。 Sometimes when I ought to have been asleep I was detected by the sound of the ramming in of the sand of the moulding boxes。 On such occasions my father let me know that I was disobeying his orders by rapping on the ceiling of his bedroom with a slight wooden rod of ten feet that he kept for measuring purposes。 But I got over that difficulty by placing a bit of old carpet under my moulding boxes as a non…conductor of sound； so that no ramming could afterwards be heard。 My dear mother also was afraid that I should damage my health by working so continuously。 She would come into the workroom late in the evening； when I was working at the lathe or the vice； and say； 〃Ye'll kill yerself； laddie； by working so hard and so late〃。 Yet she took a great pride in seeing me so busy and so happy。
Nearly the whole of my steam…engine models were made in my father's workroom。 His foot…lathe and stove； together with my brass casting arrangements in my bedroom； answered all my purposes in the way of model making。 But I had at times to avail myself of the smithy and foundry that my kind and worthy friend； George Douglass； had established in the neighbourhood。 He had begun business as 〃a jobbing smith；〃 but being a most intelligent and energetic workman； he shot ahead and laid the foundations of a large trade in steam…engines。 When I had any part of a job in hand that was beyond the capabilities of my father's lathe； or my bedroom casting apparatus； I immediately went to Douglass's smithy； where every opportunity was afforded me for carrying on my larger class of work。
His place was only about five minutes' walk from my father's house。 I had the use of his large turning…lathe； which was much more suitable for big or heavy work than the lathe at home。 When any considerable bit of steel or iron forging had to be done； a forge fire and anvil were always placed at my service。 In making my flywheels for the sectional models of steam…engines I had a rather neat and handy way of constructing them。 The boss of the wheel of brass was nicely bored； the arm…holes were carefully drilled and taped； so as to allow the arms which I had turned to be screwed in and appear like neat columns of round wrought iron or steel screwed into the boss of the flywheel。
In return for the great kindness of George Douglass in allowing me to have the use of his foundry； I resolved to present him with a specimen of my handiwork。 I desired to try my powers in making a more powerful steam…engine than I had as yet attempted to construct； in order to drive the large turning…lathe and the other tools and machinery of his small foundry。 I accordingly set to work and constructed a direct…acting； high…pressure steam…engine； with a cylinder four inches in diameter。 I use the term direct acting； because I dispensed with the beam and parallel motion； which was generally considered the correct mode of transferring the action of the piston to the crank。
The result of my labours was a very efficient steam…engine； which set all the lathes and mechanical tools in brisk activity of movement。 It had such an enlivening effect upon the workmen that George Douglass afterwards told me that the busy hum of the wheels； and the active； smooth； rhythmic sound of the merry little engine had； through some sympathetic agency； so quickened the stroke of every hammer； chisel； and file in his workmen's hands； that it nearly doubled the output of work for the same wages！
The sympathy of activity acting upon the workmen's hands cannot be better illustrated than by a story told me by my father。 A master tailor in a country town employed a number of workmen。 They had been to see some tragic melodrama performed by some players in a booth at the fair。 A very slow； doleful； but catching air was played； which so laid hold of the tailors' fancy that for some time after they were found slowly whistling or humming the doleful ditty； the movement of their needles keeping time to it； the result was that the clothing that should have been sent home on Saturday was not finished until the Wednesday following。 The music had done it！ The master tailor； being something of a philosopher； sent his men to the play again； but he arranged that they should be treated with lively merry airs。 The result was that the lively airs displaced the doleful ditty； and the tailors' needles again reverted to even more than their accustomed quickness。
However true the story may be； it touches an important principle in regard to the stimulation of activity by the rapid movements or sounds of machinery； which influence every workman within their sight or hearing。 We all know the influence of a quick merry air； played by fife and drum； upon the step and marching of a regiment of soldiers。 It is the same with the quick movements of a steam…engine upon the activity of workmen。
I may add that my worthy friend； George Douglass； derived other advantages from the construction of my steam…engine。 Being of an enterprising disposition he added another iron foundry to his smaller shops； he obtained many good engineering tools； and in course of time he began to make steam…engines for agricultural purposes。 These were used in lieu of horse power for thrashing corn； and performing several operations that used to be done by hand labour in the farmyards。 Orders came in rapidly； and before long the chimneys of Douglass's steam…engines were as familiar in the country round Edinburgh as corn stacks。 All the large farms； especially in Midlothian and East Lothian； were supplied with his steam…engines。 The business of George Douglass became very large； and in course of time he was enabled to retire with a considerable fortune。
In addition to the steam…engine which I presented to Douglass； I received an order to make another from a manufacturer of braiding。 His machines had before been driven by hand labour； but as his business extended； the manufacturer employed me to furnish him with all engine of two…horse power； which was duly constructed and set to work； and gave him the highest satisfaction。
＇Image＇ James Nasmyth's Expansometer； 1826。
I may here mention that one of my earliest attempts at original contrivance was an Expansometeran instrument for measuring in bulk all metals and solid substances。 The object to be experimented on was introduced into a tube of brass； with as much water round it as to fill the tube。 The apparatus was then plunged into a vessel of boiling water； or heated to boiling point； when the total exp
