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I knew what Mr。 Joslyn meant。 To cross the mountain ranges by rail； the engineers are obliged to wind up one side of a valley； and then； boldly crossing the head of the ravine on a high arch； to wind up the other side still； so that perhaps half an hour's journey is consumed； while not a mile of real distance is made。 Joslyn took out his pencil； and on the back of an envelope drew a little sketch of the country； which； as it happened； I still preserve； and which； with his comments； explains his whole story completely。 〃Here we are；〃 said he。 〃This black line is the Great Alleghanian；double track； seventy pounds to the yard； no figuring off there； I tell you。 This was a good straight run； down grade a hundred and seventy…two feet on the mile。 There； where I make this X； we came on the Chamoguin Valley； and turned short； nearly north。 So we ran wriggling about till Drums here； where we stopped if they showed lanterns；what we call a flag… station。 But there we got across the valley； and worked south again to this other X； which was； as I say； not five…eighths of a mile from this X above； though it had taken us eleven miles to get there。〃
He had said it was not more than half a mile； but this half…mile grew to five…eighths as he became more accurate and serious。
〃Well；〃 said he； now resuming the thread of his story； 〃it was Todhunter put it into my head。 He owns he did。 Todhunter says； says he； ‘Joslyn； what's the use of crooking round all these valleys； when it would be so easy to go across？'
〃Well； sir； I saw it then； as clear as I see it now。 When that trip was done； I had two days to myself；one was Sunday；and Todhunter had the same； and he came round to my house。 His wife knew mine； and we liked them。 Well； we fell talking about it； and I got down the Cyclopaedia； and we found out there about the speed of cannon…balls； and the direction they had to give them。 You know this was only talk then； we never thought what would come of it； but very curious it all was。〃
And here Mr。 Joslyn went into a long mathematical talk； with which I will not harass the reader； perfectly sure； from other experiments which I have tried with other readers； that this reader would skip it all if it were written down。 Stated very briefly； it amounted to this： In the old…fashioned experiments of those days； a cannon…ball travelled four thousand and one hundred feet in nine seconds。 Now； Joslyn was convinced； like every other engineman I ever talked to； that on a steep down…grade he could drive a train at the rate of a hundred miles an hour。 This is thirteen hundred and fourteen feet in nine seconds；almost exactly one…third of the cannon…ball's velocity。 At those rates； if the valley at Chamoguin were really but five…eighths of a mile wide； the cannon…ball would cross it in seven or eight seconds； and the train in about twenty…three seconds。 Both Todhunter and Joslyn were good enough mechanics and machinists to know that the rate for thirty…three hundred feet； the width of the valley； was not quite the same as that for four thousand feet； for which； in their book； they had the calculations and formulas； but they also knew that the difference was to their advantage； or the advantage of the bold experiment which had occurred to both of them when Todhunter had made on the tender his very critical suggestion。
The reader has already conceived the idea of this experiment。 These rash men were wondering already whether it were not possible to leap an engine flying over the Chamoguin ravine； as Eclipse or Flying Childers might have leaped the brook at the bottom of it。 Joslyn believed implicitly； as I found in talk with him； the received statement of conversation； that Eclipse； at a single bound； sprang forty feet。 〃If Eclipse； who weighed perhaps one thousand two hundred； would spring forty feet； could not my train； weighing two hundred tons； spring a hundred times as far？〃 asked he triumphantly。 At least； he said that he said this to Todhunter。 They went into more careful studies of projectiles； to see if it could or could not。
The article on 〃Gunnery〃 gave them just one of those convenient tables which are the blessing of wise men and learned men； and which lead half…trained men to their ruin。 They found that for their 〃range；〃 which was； as they supposed； eleven hundred yards； the elevation of a forty…two pounder was one degree and a third； of a nine… pounder； three degrees。 The elevation for a railway train； alas！ no man had calculated。 But this had occurred to both of them from the beginning。 In descending the grade； at the spot where； on his little map； Joslyn made the more westerly X； they were more than eleven hundred feet above the spot where he had made his second； or easterly X。 All this descent was to the advantage of the experiment。 A gunner would have said that the first X 〃commanded〃 the second X； and that a battery there would inevitably silence a battery at the point below。
〃We need not figure on it；〃 said Todhunter； as Mrs。 Joslyn called them in to supper。 〃If we did； we should make a mistake。 Give me your papers。 When I go up； Monday night； I'll give them to my brother Bill。 I shall pass him at Faber's Mills。 He has studied all these things； of course； and he will like the fun of making it out for us。〃 So they sat down to Mrs。 Joslyn's waffles； and； but for Bill Todhunter； this story would never have been told to me； nor would John Joslyn and 〃this woman〃 ever have gone to Australia。
But Bill Todhunter was one of those acute men of whom the new civilization of this country is raising thousands with every year； who； in the midst of hard hand…work； and a daily duty which to collegians and to the ignorant men among their professors seems repulsive； carry on careful scientific study； read the best results of the latest inquiry； manage to bring together a first…rate library of reference； never spend a cent for liquor or tobacco； never waste an hour at a circus or a ball； but make their wives happy by sitting all the evening； 〃figuring；〃 one side of the table； while the wife is hemming napkins on the other。 All of a sudden； when such a man is wanted； he steps out； and bridges the Gulf of Bothnia； and people wonder； who forget that for two centuries and a half the foresighted men and women of this country have been building up； in the face of the Devil of Selfishness on the one hand； and of the Pope of Rome on the other； a system of popular education； improving every hour。
At this moment Bill Todhunter was foreman of Repair Section No。 II on the 〃Great Alleghanian；〃a position which needed a man of first…rate promptness； of great resource； of good education in engineering。 Such a man had the 〃Great Alleghanian〃 found in him； by good luck； and they had promoted him to their hardest…worked and best…paid section；the section on which； as it happened； was this Chamoguin run； and the long bend which I have described； by which the road 〃headed〃 that stream。
The younger Todhunter did meet his brother at Faber's Mills； where the repair…train had hauled out of the way of the express； and where the express took wood。 The brothers always looked for each other on such occasions； and Bill promised to ex