"except in the fall from Loch Oich to Loch Ness, where we "differ a few feet; but the states of the water in the Lochs "make some difference, and the only bad weather I expe"rienced was during this part of the survey, so that I am not "positive that I am right. I had not time to prove the "levels, nor is it of much moment: the height of the water "in Loch Oich above the tideway is 100 feet, as near as may "be." To which Mr. Watt replied:-" As we agree upon "the level of Loch Oich the summit, any difference of level "elsewhere cannot materially affect the estimates, as the feet "of lockage will remain the same. The mistake may, how"ever, be mine, as my levels were not repeated."† The depth of water recommended by Mr. Telford was 22 feet. That of the canal as executed was in most parts 15 feet; although the bridges and locks were prepared on a scale to admit of that being increased, should it ever be found advisable, to 20 feet. Mr. Telford introduces a long extract from Mr. Watt's Report, with the following observations :— "In the year 1773, the Trustees for the Forfeited Estates employed Mr. Watt to make a survey of this track, which he "did, and furnished them with a report and estimate of the 66 66 expense of making a canal of ten feet water. This report "is so able and just, that had I considered that size of canal "as most advisable, I should have adapted the calculations "of the expense to the present day, and mentioned some "alterations which have taken place in the country since his survey was made, and should have recommended the survey "to your Lordships' attention. But Mr. Watt's views were "merely to ascertain how far a navigation of any sort was practicable, and therefore he fixed upon ten feet of water 66 as an assumed standard to enable him to make his esti"mates. I lose therefore the benefit of his particular calcu"lations; and I am under the necessity of departing, in some "instances, from his line of canal, especially at the entrances "into the lochs and tideways, in order to obtain a greater 66 * Mr. Telford to Mr. Watt, 3 May, 1802. 66 depth of water; but I have followed him wherever the cir"cumstances would permit; and I cannot resist the introducing his general description of the country through which "the navigation is proposed to be made, because, after having "examined the whole with care, I find it to be so correct, "that I could only repeat the same descriptions and dwell "upon the same points." Their levels agreed within one foot. In his Report, Mr. Watt mentions that he confined his estimates to a canal of ten feet depth of water, because he knew of none that had been executed upon a greater scale, and because his views in making the survey were principally directed to those dimensions. "It is sufficient," he adds, “in a first survey, that the possibility is established, "and the expense of one mode of communication is nearly "estimated, which I flatter myself I have done. If from my "observations the making any communication should appear 66 an eligible scheme, the matter may be minutely examined, "and the opinions of other artists obtained, concerning the "best mode of execution." It is curious, if only by way of contrast with the practice of the present day, to record the rate of payment at which the skill and exertions of a man endowed with Watt's powers of mind were then obtained. The Strathmore survey of 1770 may be taken as a specimen. On that occasion he was actively engaged in travelling and in field operations for forty-three days, usually from eight or nine in the morning till seven or eight at night, during most inclement weather, with piercing cold, and frequent and heavy falls of snow and rain; and his exertions so much exhausted his strength, as to render him, to use his own words, "unable for some time to apply him"self to any other business that required attention." His charge for that work was 801., or about 17. 178. per diem, inclusive of all his expenses of travelling and living. For the preparation of the Report and directing the execution of the map which accompanied it, he was paid the further sum of 30%-an almost equally insignificant recompense for the mere *Third Report on the Survey of the Coasts of Scotland, ordered to be printed 14th June, 1803, Appendix, p. 32. amount of time and labour bestowed, independent of all considerations of superior knowledge, accuracy, and sagacity. That the rate of remuneration of civil engineers did not rise in any very rapid ratio in the latter part of the last century, appears from a letter of Mr. Watt in 1791, in which it is incidentally mentioned that Mr. Rennie, "who is in con"siderable fame, and, I suppose," says Mr. Watt, "as well I paid as any of his standing, has two guineas a-day when "employed as an engineer;" in addition, however, it is to be presumed, to his travelling expenses and other "costs and "outlays," which was not the case with the smaller rate of pay of Mr. Watt in 1770. We have in our own time seen engineering bills, in which the rate of charges presented a marvellous contrast to those which men such as Rennie and Watt felt it right to make; while it was also found, to the further serious cost of those who had to defray the far larger amount, that the services received by them for their money were of very far less than equivalent worth. CHAPTER XVI PHILOSOPHICAL PROBLEMS TIME-PIECES - MICROMETER AND DIVIDING- SURVEYING QUADRANT BAROMETERS MEASURING DISTANCES HISTORY OF THE INVENTION OF MICROMETERS -SIR DAVID BREWSTER DE LA HIRE MALVASIA AUZOUT AND MASKELYNE- DEATH OF BESIDES all his surveying and civil-engineering, and the manifold alterations he devised in both his condensing and his wheel engines, Mr. Watt bestowed, during the years of which we have now been speaking, in concert with his friend Small, a good deal of thought on various other ingenious mechanical contrivances, which supplied pleasant amusement to their inventive and reflective brains. "We have " abundance of matter to discuss," says the great engineer; "though the damned engine sleep in quiet!" "The French, you know," says Small," offer large præmia for time-keepers. "Were I idle, I should try to win one of these. But physic "exhausts my whole faculties, and pays but indifferently. I am so made that I suffer no fatigue from thinking ever so long and attentively on a subject in which I can get for"ward; but if I am absolutely puzzled, and see no clue, my "head turns round, and I speedily become more tired than a galley-slave. Physic very fortunately furnishes abundance " of these profitable points."† "I have perfected my clock "with one wheel of nine inches diameter, which is to tell 66 66 66 hours, minutes, and seconds, and strike, and repeat, and be "made for thirty shillings." And again, "My clock of one "wheel, that shows hours, minutes, and seconds, and strikes "the hours and repeats them, is nearly finished. The striking " and repetition are good, the rest is gimcrack." § * 7 November, 1772. † 5 October, 1770. 14 February, 1771. § 16 December, 1771. 66 66 66 "You wrote me before," says Mr. Watt,* "of your clock "with one wheel. Did I ever mention to you a striking "part, regulated by a balance pendulum with live scapement, "which had only one wheel?" But some months later,t Everybody," says Small, "is too much engaged for the prosecution of schemes, so that even my clock is not prosecuted, and I have only one, which I cannot send to you; "I have just ordered a pendulum clock to be made with no "wheel at all;"-and, "when my clock with one wheel," he afterwards adds,§ "was finished, I found it too complicated, " and have now got one with no wheel, and only one sector "with seventy-five teeth. It strikes, repeats, shows hours, "minutes, and seconds, and goes eight days, with the usual "descent of the weight. This is to be ranked in mechanics, "as riddles and rebuses are ranked in poetry." 66 66 66 On which comes this comment of the sagacious Watt:"As to clocks, I do not fully conceive how you can make yours go eight days with the ordinary descent of the weight, "unless by pulleys or something equivalent, which would only "be a quibble upon a wheel; "||-thus answered by the inventor:¶"there is no quibble in my clock, and we have "now found a tolerable workman for the execution of it. "One is now making, which will show with much more accuracy than any other clock has hitherto done, the spheric phenomena relating to astronomy, sidereal and mean time, hours, minutes, and seconds, with only one wheel and one "sector. It will also strike and repeat the hours. The wheel "has 72 teeth and the sector 75 only;"-" I have had a new scapement made for watches, of such marvellous virtue, that "if the maintaining power is quadrupled, or decupled, the "number of the vibrations will be lessened, but not above ten "in twenty-four hours."** And-"I have taken out a patent "for improvement on clocks and other time-pieces, and want "you vastly to help me to draw up the specification, which 66 66 * 24 December, 1771. 16 November, 1772. 17 January, 1773. 27 January, 1773. **15 March, 1773. |