1845.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



151 



Tlie gates are worked by four douUi'-purcliase capstans, with gear- 

 ing, and S inch cliaius. All the bolts were dipped in hot linseed oil 

 l>efore being driven, and all the surfaces of iho iron, both inside, as 

 well as those outside, received three ooits of oil paint. 



The timber, under water, exce|)t at the meeting of the cills and 

 mitres, is all covered with scupper nails to keep out the worm. 



The weight of the gates and the apparatus connected with them is 

 as follows: — 



Tons. Cnls. 

 •.'4 U 



. . :■•-> l.'ij 



Ciist-iron work In the gates 

 Wrought iron In ditto . 

 Hrui .... 



I* 



Ight of gates, exclusive of timber , 

 in segments, dUs, capstans, an- \ 



Total 

 Cast! 

 chors, and otUer fixtures 



Tlie dock is onlf about 3 acres in area, which is considerably less 

 than what was originally intended, but owing to opposition, its size 

 was reduced while the Bill was in Committee, which is to be regretted, 

 as the river wall and the entrance, which are the most expensive 

 parts of the work, remain the same, and the enlargement could have 

 been executed, at a very small ;idditional cost. At the suggestion, 

 however, of ^[r. Walker, (Pres. Inst. CE.) a provision has been made 

 for a futuri' extension, by having an opening at the inner end of the 

 dock, and filling it up in a temporary manner, with sheeting piles held 

 back by iron tie rods, und puddled behind with clay; these sheeting 

 piles may be made to form part of a cotVer-dam, and an extension may 

 be thus made, at any future time, without closing the dock. 



The ground on which the dock stands, is sand, or sand and gravel, 

 which is full of water, to within a few feet of tlie surface; and owing 

 to the failure of an attempt to form a graving dock, in similar ground 

 in the neighbourhood, about 50 years ago, great fears were entertained 

 that it would be impossible to make a dock to retain water ; therefore 

 it was not thought advisable to proceed with the plan, until Mr. 

 Walker's opinion was taken as to its practicability. His report being 

 favourable, the work was contracted for in the spring of 1839. The 

 result has justified the most favourable anticipations, for there have 

 been no serious difficulties to contend with, and all parts of the work 

 stand well. 



The tide work, in founding the outer wall, was at first found to be 

 very tedious, and expensive, owing to the great leakage, as the found- 

 ation was considerably below low water, unlil Mr. Smith, of Montrose, 

 the contractor, had a steam-engine erected to work the chain-pumps. 

 This was done by common ropes passiug over sheaves, and so con- 

 veying the motion in a very simple manner, sometimes above GOO feet 

 from the engine-house to the coft'er-daras; the work then proceeded 

 rapidly. 



The coffer-dams were wooden boxes, about 25 feet long by 15 feet 

 broad, sunk as far as they could be got down, and afterwards piled 

 inside, with thin sheeting piles, to keep the sand from running in 

 below. 



The gates were contracted for, and made by Mr. Stirling, of the 

 Dundee foundry (Dundee). 



The dock was commenced in June 1839; the gates were completed, 

 and the water was admitted in July, 1843. The whole expense of 

 the dock and the gates, but exclusive' of the Act of Parliament and the 

 purchase of property, was about £40,000. 



The dock enters trom the river South Esk, which forms the harbour, 

 and is kept open to the depth of 7 feet at low water, and 22 feet at 

 high water, of ordinary spring tides, by a strong scour into and out of 

 the basin at Montrose, an estuary of nearly four square miles in ex- 

 tent, immediately behind the town. The dock has a depth of 20 feet 

 at high water of spring tides, and IG feet at neap tides, and the en- 

 trance being as before stated, 55 feet in width, it can always receive 

 at high water the largest steamers navigating the east coast of Eneland 

 and Scotland. ^ ^ 



Rain in Aigikrs,— M. Don, who is charged with the operations of drain- 

 ing In Algeria, lias transmitted the result of liis observations since January 1838, to the 

 Academie des Sciences, on the quantity of rain that falls annually at Algiers. M. Don 

 divides his observations Into periods of four months, setting out with the opinion in the 

 country that rain fails during months of the year, viz. Irom the Ist of Sept. to the 30th of 

 April. In the first three yeors this opinion appeared to be well founded, the average of 

 Uay being greatly iufvrior to that of Sepiember; but in the three fullouing years the 

 average of May was higher ; and the observations of the average of seven years show 'that 

 September is less rainy than May, so that the dry months are really only three— June 

 July, and August. M. Uon states that the winter which has just ended was unusually 

 severe. The quantity of snow that fell and remained for several days on the ground was 

 unprecedented; but tnetbermooieter never fell belovr3 deg, centigrade under the freeiinf 

 point. ' 



ON IRON ORE.S, 

 " Erperimental researches into the properties of the Iron Ores of Sama- 

 KOFr, ill Turkey, and of the ILematile Ores of Cumberland, i*iVA a vieui 

 to determine the best means for reduciny them into the cast and malleable 

 states ; and on the relative strength and other properties of cast-iron from 

 the Tiir/dsh and other Hwrnatite Ores."~\\y William Fairbaihn, M. Inst. 

 CE. {Paper read at the Institution of Civil Engineers, Session 1844.) 



In the smelting and manufacturing of the poorer iron ores, as they are 

 commonly called, being those in which a large pro[iortion of alumina, silica, 

 and other foreign matters are contained, many important improvementt have 

 in modern days been effected ; hut in the reduction of the richer sorts— 

 hematite ores, those more nearly approaching pure iron, with very little ad- 

 mixture of other substances, there lias heen scarcely any change from the old 

 and expensive methods, which have for several centuries prevailed in this and 

 other countries. It is remarkahle, that the proprietors of the richer mineraU 

 shotdd have allowed the makers of iron from ores of leaner quaUtv, such as 

 the hlackband and kidney ores, to have so far outstripped them, iixcept the 

 successful experiments of Mr. Heath, at the Works of I'orto Nuovo, in the 

 Kast Indies, and the attempts now making by the Cleator Companv, near 

 Whitehaven, there are few instances of improvements in the smelting of rich 

 ores, either in this country or on the continent. It has heen stated, that the 

 Swedish iron manufacturers have introduced some alterations into their 

 works, hut they appear to be of minor importance, and to he scarcely enlilled 

 to the name of improvements, upon the old process used in that country for 

 a long series of years. 



It is to Mr. Ohanes Dadian, (Assoc. Inst. CE.) an active and enterprising 

 .\rraenian, in the service of the Sublime Porte, that we are indebted for the 

 present inquiry ; and by that gentleman's determination to surmount every 

 obstacle, and to solve the doubts of some eminent chemists, the present re- 

 sults were obtained. Amongst other duties devolving upon Mr. Dadian in 

 his recent vi>it to this country, was that of placing in the hands of compe- 

 tent persons, some samples of ores which were sent from Turkey, for the 

 purpose of experiment. The first samples were small in «juantity,but a more 

 recent supply, accompanied with some specimens of bituminous coal, enabled 

 the experimenters to enter upon the subject with increased conlidence, and to 

 pursue the inquiry with much greater prospects of success. In addition to 

 this, Mr. Dadian had full power to engage persons duly qualified for the in- 

 vestigation, and whose skill and practical knowledge, would entitle them to 

 the support and confidence of their employers. In consequence, Mr. W. N. 

 Clay was engaged as a chemist and metallurgist, and Mr. John Hague as 

 engineer. 



As the greater part of the experiments were conducted under the superin- 

 tendence of those gentlemen, their separate reports are given in the order in 

 which they were made ; and to prevent confusion the facts are recorded as 

 they occurred, from time to time, in the experiments. 



Previous to Mr. Dadian's visit to England, he had collected information 

 relative to the fuel, limestone, &c., in the district of country where the ore 

 is found ; and from the abundance and quahty of the materials, it is presumed 

 that a moderately cheap iron of very superior quality may be obtained. From 

 the description of the country, as given by ilr. Dadian atul hy Mr. Zohrab 

 (.Vssoc. Inst. C.E.), who visited the locality some years since, it appears, that 

 the ore is brought down the rivers from the higher districts, and is deposited 

 in the lower valleys, at a short distance from the sea ; extensive tracts of 

 country are thus covered, to a depth to insure au almost inexhaustible sup- 

 ply- 

 Before any definite plan could be adopted for the reduction of the ores, it 

 was deemed necessary to ascertain, by careful analysis, their composition and 

 value, and for these objects Mr. Dadian, when last in Paris, consulted Mon- 

 sieur Dumas, the chemist, and from that gentleman he received a favourable 

 report : that report is not in the author's possession, but from statements re- 

 ceived, it appeared only to have differed in a slight degree from that of Mr. 

 H. H. Watson, of Bolton, whose analysis of one of the samples (which may 

 be taken as a fair average of the whole) gave — 



One atom of metal 28 + one atom of oxygen 8 = protoxide of Iron. 

 Two atoms of metal 60 + tliree atoms of oxygen 24 = peroxide of Iron. 



84 metal + 32 Oxygen — UG black oxide. 

 Then 116 ; 84 : : 88 : 6.'i7L* + quantity of metal per cent, in the ore in question by theory. 

 In this statement Mr. Watson observes, " that the oxide readily dissolves, 

 when the ore is heated in powder with hydro-chloric acid," aiid by thus 

 treating 100 grains of the ore, he obtained a .solution of the oxide, and had 

 12 grains of silicious earth undissolved; the proportions would therefore 

 be — 



Protoxide of i: 

 Peroxide of in 

 Silicious eartt 



.::::} 



From the above it is evident that the ores are nearly pure oxides of iron j 

 they are rich in quality, highly magnetic, and may be easily separated from 

 extraneous matter by the magnet. In some of the processes this separation 

 may or may not be necessary, but iu case the siUca be found injurious, th« 



20» 



