it may without sensible error be considered as a straight line.. With regard to temperature, every precaution was taken to prevent error. The thermometer used was made by Mr. Troughton for the latè Sir George Shuckburgh. It is divided into half degrees, and the height of the mercury may be estimated to one-tenth of a degree. It has been already observed in the preceding part of this paper, that the thermometer was approached only at the first and last coincidences. The experiments themselves afford, it is presumed, a sufficient proof of the stability of the knife edges. Every care was taken to form them in the first instance as perfect as possible, and after four sets of experiments had been made they were found on re-measurement to have suffered no perceptible alteration; and it is evident by the near agreement of the results, that they remained uninjured during the succeeding experiments: it is difficult therefore to conceive that any error can have arisen from this source. I may here remark, that the method I have employed in determining the length of the pendulum possesses other advantages besides that of superseding the errorsarising from unequal density or figure; and one, not the least considerable, is, that after a very few vibrations the true length of the pendulum is bounded by certain known. limits. Thus in the two first sets of experiments, after the re-measurement of the distance between the knife edges, we may remark, that when the slider was at 29 divisions, the number of vibrations (the great weight being below) was, 86057,85, and in defect; and when the slider was removed to 19 divisions, the number of vibrations was 86059,41, and in excess. The true number of vibrations then is evidently between the two, and the ut VOL. XXXIV.-SECOND SERIES. Gg most most extent of error in using either of these numbers must fall short of 1,73, their difference when reduced to the same temperature. But if the mean be employed in the computation, the length of the, pendulum will be found to differ only about four ten-thousandths of an inch from the mean result given in the foregoing table. It may not be unnecessary to add, that every experiment made has been retained, nor do I consider any one as less entitled to credit than the rest, excepting that marked A, in the table; and that, only because the rate of the clock was not observed on the day of the experiment, but was taken to be the same as the rate of the following day. The length, then of the pendulum vibrating seconds in vacuo at the level of the sea, measured at the temperature of 62° of Fahrenheit, appears to be Inches. By Sir G. Shuckburgh's standard.... 39,13860 39,13717 By Bird's Parliamentary standard....39,13842 the Latitude of the place of observation being 51° 31′ 8′′,4 north *. An objection might be urged against the use of the knife edge, on the ground that being an elastic substance it may possibly suffer temporary compression, and thus perhaps introduce a source of error. In order to meet any doubt that might arise on this important part of the subject, it is my intention to commence a series The latitude was deduced from the data contained in the trigonometrical survey; Mr. Browne's house bearing from Portland Chapel 74° 38' 50" west from the north, the distance being 283 feet. This differs only o", 1, from the latitude determined by Mr. Browne from a great number of observations. of of experiments with a pendulum of the same construction as that which has been described, but vibrating on cylinders instead of knife edges; and I trust soon to have the honour of laying the result before the Royal Society, London, July 1817. *The Plate referred to as Plate V. in page 92, (No. CC.) is not given, being deemed unnecessary to illustrate the subject. Page 83, No. CC, the following should have been inserted after the word figure, line 7, from the top, "A Plan of the Pendulum is given in Plate V. Fig. 1.” On the Storing of British Grain when Cheap and Plentiful; and on the Best and Simplest Mode of Preserving Grain. With a Plate. From the EDINBURGH FARMER'S MAGAZINE. A NEW building for storing and selling victual was erected some years ago by the orders of a nobleman, whose habits of benevolence inclined him to be at this expense for the benefit of a village that he had long and kindly patronized. It was ready in the year 1815; and the crop of that season was most abundant, and of the finest quality. The farmers could not sell their corn; and as they had not the means of preserving, and were therefore obliged to part with their grain, it was freely used in feeding live-stock; and what could be sold, was disposed of at very low prices. Every one in that part of the country thought it the best opportunity that could occur, for storing the new building with grain and meal. It could have been done at a rate so low as to preclude any risk of loss, and to offer a considerable prospect of gain. The farmers would have been accommodated by such a market; and the supply would have served the village a long time, on easy terms, and without hazard or alarm. All this might perhaps have been done, if it had been in the power of those concerned to ensure the preservation of the victual till it should come into demand: but how to do this was unknown; and, of course, there was no supply stored. A great waste occurred in the victual of the district;-the farmers had no proper market for their surplus grain;—and when the bad and unproductive crop of 1816 came to be used, the inhabitants were reduced to extreme distress-the farmers could not sup-. ply them—and the general recourse was to sea-ports for grain imported chiefly from Russia. Even this remote and dear-bought supply was very sparingly to be had; and not until the country had suffered much from scarcity, after being agitated by apprehensions of famine, threatened with internal convulsions, and exceedingly drained of the little money that circulated within it. This is a case taken correctly from fact; and it very strongly illustrates the state of Great Britain and Ireland, at the same periods of time. The surplus grain of a very fine season is not preserved, as it ought to be, when there is not a brisk foreign market for it;-but it goes to waste, or almost for nothing:-And then comes the season of emergency-pregnant with hardships, full of alarm-draining the kingdom, and almost convulsing it. There is no propriety, certainly, in cramping British manufacture by any laws in favour of agriculture; for these these great sources of national wealth and prosperity are not-opposed in their several interests to each other. It is not necessary to prohibit the import of foreign corn, which has been absolutely necessary for some weeks past for the subsistence of our population. But who will venture to deny that our own crop 1815 might have covered the defects of the succeeding crop, if the surplus had been judiciously stored at home? Even this measure might not have been proper, if there had been a demand for that surplus from abroad; but in absence of all demand for it, abroad or at home, it is impossible to deny, that, if that surplus could have been preserved from waste and damage, it would have been a wise and most important measure. Perhaps it would have prevented a great part, if not all of the unusual distresses, alarms, and convulsions, occasioned by the defects in the crop 1816. What has thus occurred in two seasons, and to such an extent, may instruct us for the future. It may show the wise and necessary policy of storing our own surplus corn, in case there is not a market for it; and we may learn from Russia, not only that such a measure is important, but also that it is practicable, and that it may be accomplished by simple means. The British farmer, and perhaps also the landholder, may oppose the serious preliminary objection, that the price of their corn cannot be wanted, and that it may not be in the power of these classes to wait a better demand and higher price. The public may also be alarmed at the idea of storing up the corn of the country, instead of selling it all off at such prices as it may happen to bring. These objections, though specious, are of no real weight. Let the farmer and landholder follow the system of preserving and storing their corn, only in so far as to promote their several interests, by the preven |
