Engineering Duties ode the Birmingham Railway Off~t~. :~g phenomena required, so as to leave no gap or detieiene~ in the eVideli~ of identity. The shock~ in very varied circumstances d position, wasp~ cured; the galvanometer aflbcted; magnets were madej a wire was heatedi polar chemical decomposition was efl'eeted, and the spark obtained. By comparative experiments made with the animal and a powerful Leyden battery, it was concluded that the quantity of force in each shock o f the former was very great. It was also ascertained by all the tests capable of bearing on the point, that the current of electricity was, in every case~ from the anterior parts of the animal through the water~ or surrounding eonductors~ to the posterior parts. The author then proceeds to express his hope that by means of these organs and the similar parts of the torpedo, a relation as to aclion and reacllon ot the electric and nervous powers may be established experimentally; and he briefly describes the form of experiment which seems likely to yiehl positive results of this kind. Ibid.
PrOgTCSS 01" C i v i l
Engineering.
Engineering Dulies of lhe Birmingham Railway Officers. The labours of the engineers, it is ahnost needless to state, commenced long before the ground was broken. In fact, many of them were employed in getting assents to our bill, from the landowners, who have shown them. selves so wise in their generation. Then came the various surveys and levellings required for fixing the line ; then the designing and drawing of bridges aml other works in detail, in order that approximate estimates of costs might be laid before Parliament. When the period arrived for executing tl~e works, it was necessary to calculate the time which those at the greatest magnitude would be likely to occupy, so that they might be let to the contractors in such an order, that the whole might be simultaneously completed, as far as possible, with reference to the successive openings of portions of the whole line, which was desirable, not only as a measure of pecuniary interest, but to get the road in good repair, and to drill every one into his particular duty. The order of letting the contracts having been decided, assistant and sub.assistant engineers were appointed, as re, quired, upon the general principle of dividing the whole line into four districts, and each district into three lengths, so as to place about ten miles under the immediate superintendence of one sub-assistant engineerj thus each assistapt engineer had three sub-assistants, being all subordinate to one engineer in ~hief. When any particular portion of the works was to be prepared for letting, the sub.assistant engineer, under the direction of his superior~ had to revise all the parliamentary surveys and levels with the utmost care, and draw to a large scale very accurate plans and sections~of the land, in order that the quantity of excavations and embankments might be obtained as nearly as possible. It was also necessary to make detailed plans anti working drawings, elevations, and sections of every bridge and culvert which carried a road or stream across the railway~ or which carried the railway over a road or stream. "l'hese~ being roughly sketched by the engineer on the spot, were sent to the chief office, to be fairly drawn out with full details, and upon a
Pro£~rese of Civil Engineering.
2 80
uniform system laid down by the principal engineer; the object being to put them in such a shape that parties wishing to tender for any of the contracts might clearly understand the nature of tile works, and make accurate estimates from the drawings without difficulty. The limits of each contract weredetincd withret~rence to the most convenient execution of the works, regard being had to the disposition of the earth win-ks, so that each contractor might make his embankments with the materials yielded by his excavations, as far as it was practicable; care being taken that the agaregate amount ,Jf the contract sh¢mld not exceed tile means of tile gene. rality of persons in the habit of tendering for such works. A contract of 10I),()(](Jl. was thotJght a very responsible undertaking; anti the experience of the l,,mdon and Birmingham Railway has shown that those a,nounti~ t% or excecdir~g, that sum, have called tbr extraordinaryexer. lions. ()t lhese there have been seven upon the whole line; four were very soon relinquished by the parties origit~ally contracting for them, and the remainit, g three executed with great difficulty. The drawings being completed, and the limit~ of the contracts fixed, de. tailed specitications were drawn up, under the engineer in chiel's superin. tendence; the whole was ttlcn submitted to the inspection of parties willing to tender fi)r the works, wl~o, onan appointed day, delivered in their re. spective estimates; and the lowest tender was generally, but not invariably, accepted,~regard being always had to the charac(er and means of the parties. The whole of these extensive and important works were let at prices which were under the estimate of the engineer in chief. The orig;nal contrac.t dra;vings were signed by tile engineer in chief and tile contractor, and preserved as documents. Three copies of each, however, had to be ma(le out~one for the use of the committee, onelor the engineer i~J chief, and one for the assistant engineer. When it is borne in mind that the engineering works of tile whole rail. way, in accordance witl~ tile above system, were divided into thirty separate divisions, each requiring its own set of drawings, estimates, and specifications, and that all these works, with two unimportant excepti(ms, were let to various contractors, between May, 18,34, and October, 1835, it will be perceived that an extensive and efficient drawing establishment must have been kept at work. Speaking in round numbers, we must say that for eighteen months, not less than thirty drawings per week, each requiring two days' work from one pair of hands, were turned out from the engineer ia chief's office.~Lecounl's ttistorg of the .Birmingham g~ailway. Lond. l%ieeh.~lago
Plan for Detecting the Displacement of Rails, and of Preventing .[teeidentson Railwags. Captain Smith, It. N., suggests the following plans for giving, additional safety to railway traveling',--For the. purpose ofdetectin~ the disolacement of rad on any hne of road, tile policemen stat oned for its protect on should be desired to pace from one station to tile other, onee or twice during their watch, drawing after them a staff along the edge of the raib the staff being fitted with a hook on the end, so formed as tofit the edge of the rail. It appears to me, that by this simple and unexpensive plan, the slight. - a
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eat derangement would be detected with much greater certainty than if loft