IS45.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



3S3 



quired, having only ten feet at low, and twelve feet at high water, with a 

 breadth varjiui? from 90 to IJO jards. Its edfies are carefully marked 

 throuahuut by buoys. It may with truth be said, liowever, th^t the un- 

 derlaliiuK has proved successful, siuce not only do all the country craft 

 use the channel, but the Calcutta steamers also. The " Nemesis" and the 

 " Pluto," on their return from China, came this way, and thus in coal, &C. 

 ellccled a saving of lOU/. sterling. But, perhaps, the most striking illus- 

 trationoflhe value of the I'auaiban, or, as we should rather call it, the 

 Mouteith Channel, is supplied by the fact that whereas, before the works 

 were undertaken, the amount of tonnage that traversed the strait was 

 from 20,0110 to 23,000 tons a year, it has now increased to upwards of 

 100,000 lous in the same period, or four times the amount of what it was 

 before. 



CARROW RAILWAY BRIDGE. 

 This massive structure is fast approaching to completion, and in the space 

 of about another week. Varmiiuth and London will be connected by one 

 continuous Hue of railway. This bridge presents rather a novelty in rail- 

 way engineering— it being the first swing-bridge which has been thrown 

 over a river to serve the purpose for which drawbridges were formerly 

 used. It is made entirely of cast iron, and is supported upon a pier com- 

 posed of 10 piles, sunk in the bed of the river. The roadway is 10(i feet 

 long, and projects at an equal distance im each side of the pier. The 

 whole weight of the bridge rests on a bed plate, which weighs 20 tons, 

 and from this plate is suspended by 8 rods another plate, the object of 

 which is to carry the centre for the spindle. The spindle works in a 

 water-tight casing. ()u the top of the bed-plate is the roller frame, which 

 consists of b wheels; and so easily managed is this immense carriage way, 

 which projects 53 feet on each side of the pier, and weighs upwards of 

 160 Ions, that by the machinery attached to the pier, the " girders," or, 

 to speak le.ss technii ally, the whole bridge can be moved in the space of 

 one minute, by a single man. There is a peculiarity in the construction 

 of this bridge which distinguishes it from others on the same principle, 

 which consists in the weiglit not being supported, as in the old bridges, by 

 the rollers alone, but resting partly on the spindle, and partly on the 

 rollers. The carriage way is to feet 6 inches broad. The approaches on 

 both sides of the river are 20 feet long, and they rest on 3 rows of 4 piles 

 each, which are graduated to a level with the line. These piles vary 

 from 2 to 3 tons in weight ; and some idea may be formed of the immense 

 quantity of iron used, when it is stated that there are 24 of these piles 

 supporting the approaches, 10 forming the pier, and 10 cut water piles. 

 There are upwards of 2li0 tons weight of cast iron altogether in this 

 bridge. f)u the lop of the bridge two beautifully constructed lamp-posis 

 are erected, which will display red or green lamps, according to the po- 

 sition of the " girders." If the girders are swung across lor the trains to 

 pass over, the green light wiU be used ; but if the connection is taken 

 away, a red lamp will intimate that circumstance. The pier on which 

 the bridge rests is IG feet in diameter, and is about 20 feet from one bank. 

 The water way which is thus given is 45 feet ti inches, and it will 

 always be kept open for the navigation, unless when it may be necessary 

 to swing round the girders for the passage of the trains. We understand 

 that it is also contemplated to construct a basin close to the bridge for 

 the lauding of goods, which we have no doubt will be hailed with consi- 

 derable satisfaction by those for whose use it is intended. It is expecled 

 that the works in connection with the bridge will be completed next 

 week. — Norfolk At us. 



CODE OF INSTRUCTIONS FOR SURVEYORS, 



Deduced from tlie Standing Orders, Sfc, adnfiied for central Utility in 



preparing the Plans and SeeUons of Proposed Kailuayfor Parliamentary 



Deposit. 



Tht plan mnst be upon a scale of at least 4 inches to a mile, and must 

 describe the line or situation of the whole of the proposed work, and the 

 lands in or through wliith the same will be made ; and also any comniu- 

 uication intended to be matie with the proposed work. 



The (ieneral Act enables the company to divert their Railway 100 

 yards on either side of the line shown on the deposited plans ; excepting 

 where the line passes through towns, or continuous houses, and then to 

 the extent of 10 yards only ; the limits of such deviation on each side of 

 of the line of railway must be defined upon the plan, and the lands included 

 within them must be shown. 



It is not essential that the limit of deviation should always extend to 

 100 yards where circumstances {e.g. the existence of a farmstea<l, or 

 turnpike-road, or a park), render it advisable to restrict the power lo 

 deviate within narrow limits. Upon this latter supposition, the line of 

 deviation will be drawn so as to exclude the excepted propeily, and the 

 lauds beyond that line, although within 100 yards, need not be described 

 or numbered. 



If the plan is on a scale less than a quarter of an inch to every 100 

 feet, there must be an additional plan upon that scale ( ^ inch 1000 feet) 



of any building, yard, court yard, or land, within the coiirtilage of any 

 building, and of any ground, cultivated as a garden, included within the 

 limits of deviation. 



1 hese enlarged plans are so frequent a source of error, as to render it 

 usually expedient to draw the whole plan to the enlarged scale. 



The plan is to exhibit thereon the distances, in miles and furlongs, 

 from one of the termini ; if the plan is not lithographed, the distances will 

 he best marked in ligures of red ink, to distinguish them from the tigures 

 of the field-, which will be in black ink. 



A memorandum of the radius of every curve, not exceeding one mile 

 in length, must be noted on the plans in chains where ihe curve occurs. 

 Mhere a tunnel is intended lo be constructed, it must be marked by 

 a dotleil line on the plan. 



Each distinct properly, divided by any visible boundary from another 

 property, should have a separate numtier, with this exception, that any 

 collection of buildings and grounds wilhin the curtilage of a building be- 

 longing to one person, and in one occupation, may be described under 

 one number-thus, " Farm house, yards, garden, barn, and sheds." 



When it is necessary to interpose a number, a duplicate number should 

 be added, thus, 8» 4a. 



The numbering should commence in every parish. All lands include<l 

 witliin the limits of deviation showtf by lines drawn on the plan, and all 

 lands which those lines touch, must be numbered and described if the 

 limits of deviation are not deliued, all the property shown un the plan must 

 numbered and described. 



1 ublic roads should have a separale number, in each parish, where 

 they appear on the plan. I'rivaie or occupation roads should have a 

 separate number, if fenced od from adjoining land ; so footpaths, if re- 

 paired by Ihe parish, or if fenced oil', should be numbered. Navigable 

 streams, and mill streams, must be separately numbered. 



The section must be drawn to the same horizontal scale as the plan, 

 and to a vertical scale of not less than one inch to every 100 feet it must 

 show the surface of the ground marked upon the plan, and traversed by 

 the proposed line of railHay. 



It must exhibit by a line the intended level of the upper surface of the 

 rails, and it must show an uniform datum horizunlal line the same 

 throughout the whole length of the work and its branches, and referred 

 lo a Sxed poiut near cue of the termini, and stated in writing on the 

 section. 



This fixed point should he some marked unvarying object, easily ac- 

 cessible 10 the public, e. g. a tide-mark, chiselled in a dock gate, the 

 plinth of a pillar, or other public building. 



The surface water level of a canal at a particular spot would not be 

 good, because ihat level varies; the surface of a road, without stating 

 the particular point, would also be bad for vagueness. 



The distances from one of the lermini must be marked along the datum 

 line in miles and furlongs, to correspond with the distances marked on the 

 plan. This rule allord a frequent test of inaccuracy. 



A vertical measure from the datum line to the line of railways must 

 be marked in feet and inches at each change of the gradient or inclina- 

 tion, and the proportion or rate of iucliuation between each and such 

 change must also be marked. 



AV'herever the railway is intended to cross any turnpike road, public 

 carriage road, navigable river, canal, or railway, is intended to form a 

 June tion with a railway, the distance of the surface of those objects from 

 the upper surface of Ihe rails must be marked in figures upon the sec- 

 tion, at the point of crossing or contact; and even it the levels coincide, 

 that fact should be slated upon the seclion. 



Where a railway ciosses a road or navigation, or is crossed by a bridge 

 or viaduct, the height and spaa of each must be marked. 



The extreme height of the surface of the railway over the surface of 

 the grounil must be marked in tigures in the case of every embinkment, 

 however trifling — and likewise in every cutting the extreme depth of the 

 railway below the surface of the ground must also be marked in tigures. 



If any alteration is intended to be made in the present level or rale of 

 inclination of any turnpike road, carriage road, or railway, ihat altera, 

 tion must be staled on the section ; the road or railway must be num- 

 bered, and there must be a cross section (with a reference to that num- 

 ber,) on a horizontal scale of one inch to every 310 feet, and oo a verticl^ 

 scale of one inch to every -W feet. 



The cross section must show in figures, as well as by measurement, the 

 present level and ;lie intended level of the road. 



Intended tunnels and viaducts must be marked in the seetion, and 

 special care must be taken that the lengths of the tunnels on the plan and 

 section agree. 



A horizontal and vertical scale roust be given on the plan and scctiOD 



The scale and datum line, as well as the otiier foregoing requisites 

 must be shown upon each plan for deposit with Ihe parish clerks. 



It must also lie borne in mind, that, where tiie levrls of any road is 

 altered, the ascent of any turnpike road must not be more than one foot 

 in 30 feet ; and of any other public carriage road, nut more than one 

 foot in 20 feet. 



The pattern plan and section annexed to the standing orders was drawn 

 several years ago, and cannot now be considered as a safe guide alune,as 

 the standing orders have since iindergoue much alteration. 



A published map upon a scale of nut less than half an inch to a mile, 

 with the proposed line of railway laid down, must be deposited before the 



