1842.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



415 



was this; — viz., adopting the German instead of the French principle in edu- 

 cating the mechanic. The French begin by tlie figure and sound art— and 

 the artizan thus educated carries sound art to ornament. TheGerm.ins begin 

 by ornament, and mal<e the figure and sound art tlie second step — and the 

 Germans never recover the false taste of their education. 



It is not yet too late to remedy this great mistake, by passing a law in 

 the Council that every mechanic, as at Lyons, should be obliged to begin by 

 the figure ; and if this he tint passed, I predict a corruption of taste in arlizan 

 and artist, uhich will throw the art into Iiideous confusion for years. 



London, Nov. 7, 1842. B. R. HAYDON. 



ON THE RELATIVE PROPERTIES OF IRON, 



Made by tlie use of Cold and Hot Air Blast, in the Smelling Furnace ; lateli/ 

 read before the West-Riding Geohgical and Polytechnic Society. 



By Hesky Haetop, Civil Engineer and Mineral .Surveyor. 



Ill the early part of the year 1829, the use of hot air in the smelting fur- 

 nace, for the manufacture of cast iron, was introduced at the Clyde Iron 

 Works, near Glasgow, and at the fourth meeting of the British Association, 

 held at Edinburgh in 1834, Dr. Clark gave an account of its success as 

 follows : — 



That in their previous operations with cold air, 8 tons, 1 cwt., 1 qr. of 

 splint coal (made into coke, at a loss in weight of 55 per cent.), were required 

 to make 1 ton of iron. 



With the use of air heated to about 300° Fahrenheit, 5 tons, 3 cwt., 1 qr- 

 of coal (in coke) produced a ton of iron, in addition to which, 8 cwt. of 

 coals were used for heating the air. 



In 1833, the temperature of the air used being G00° Fahrenheit, it was found 

 that raw coal (not coked) might be used, which circumstance further reduced 

 the quantity of coal required in the furnace to 2 tons, 5 cwt., 1 qr. per ton 

 of iron made. 



Not having been present at Edinburgh, on the Association's meeting, the 

 following year, in Dublin, I stated that the case had not been correctly re- 

 presented to Dr. Clark, 1 inasmuch, as for some time previous to 1825, a 

 saving in the coking operation had been made at every well-conducted iron 

 work, by which a ton of iron covdd be made with 5 tons of splint coal in the 

 furnace, when cold blast used, so that in reality a saving only took place by 

 increasing the temperature of the air. so far as to enable Ihem to use coal 

 uncoked in the smelling furnace, from 5 tons to 2 tons 15 cwt., or 2 tons 

 5 cwt. 



The account, therefore, as regards economy, by the use of hot air, will 

 stand thus : — 



tons. c«t. s. d. £ s. il 



Saving in coal used in the furnace 2 5 5 11 3 



In Coker's Wages ... 023 



£0 13 6 



' A similar misrepresentation has also been made to Mr. Mushet, by reason 

 of which he has been led into an error so far as to state in his most valuable 

 work on iron and steel, pages 922, 923, that the materials used at the Milton 

 Works in December 1834, with cold blast, were for each ton of iron made- 

 tons, cwt. lb. 

 Coals ..... 6 3 2 



Ironstone .... 4 1 



Limestone .... 13 



At the same works in December 1836, with hot blast — 



tons. cwt. qrs. lb, 

 Codls per ton of iron in the furnace .2 4 3 14 



Ironstone 3 11 2 21 



Iron Ore 1 U 



Limestone IG 14 



It is. however, well known, that on an average of the year through, previc.-us 

 to April, 1829, wlien cold blast was used at the Milton Works, the materials 

 consumed were — 



tons. cwt. qrs. lb. 



Coals in (he furnace . . 4 IS 0") per ton 



Ironstone do. . . 3 14 3 9 >■ of Iron 



Limestone do. . . 14 3 23-1 made. 



And in comparing this with the make by hot air, in December iS3li, (one 



Against this may be set down — 

 A greater quantity of ironstone used 



per ton of iron made . 

 Extra wear on ditto 

 Coal to heat the air used 



8 G 



2 



I 3 



3 6 



10 



£C 5 7 



Saving in materials by the use of 



hot air, per ton of iron . . 7 11 



To which saving may be added a further sum of is. Id. per ton, for the 

 greater quantity of iron produced from each furnace, when hot air and coals 

 are used, making the total saving of 12.!. Grf. per ton of pig iron. 



But in 1835, the deterioration in the value of iron so made was about 

 17s. 6rf. per ton, as I stated at Dublin, and at the present time, (March 1842,) 

 I have no recantation to read so far as the above observations go. 



In Dublin my observations on the deteriorated value of hot blast iron in 

 the market of 17s. 6d. per ton were contradicted, but after seven more years 

 of unceasing application, practised in the manufacture on a very large scale, 

 of numerous experiments by indefatigable practical men of great abiUly, of 

 the attention of learned professors of chemistry, mineralogy, and geology, 

 together with the aid of that no inconsiderable engine the public press, the 

 price of pig iron so made is .32s. G</. per ton below that made by cold blast 

 in the smelting furnaces.^ 



If you ask why iron so made is sold for 32s. 6rf. less in the market, the 

 answer is 1st, " its great weakness under impact, and therefore its total uii" 

 fitness for most purposes in which the greatest weight of iron is used.^ 2nd. 

 Its greater loss in rcmelting in the cupola of 2 cwt. per ton. 3rdly, The great 

 irregularity in the contraction of castings when cooling, if made from hot 

 blast iron, on which account many castings of different sizes are produced 

 from the same pattern, causing 'great expense in their after fitting, or if this 

 expense is not incurred, great defect in all machinery. Sec,, so made. 4th. 

 Its unsoundness, that when made into castings require to be turned, bored, 

 or planed, l&c , on which occasions, if the surface operated upon is not de- 

 fective on its entire area, a defect so considerable w'ill show itself, probably 

 when nearly finished, that both the casting and the great expense bestowed 

 upon it will be thrown away, and in many such cases the expense of making 

 the casting itself will be at least three times greater than even the present 

 great diflerence in the value of the two kinds of iron. 



I need not unnecessarily occupy your time further than by going more 

 tully into the first of these points, the great weakness, under impact, of hot 

 blast iron. 



of the best months in the year for iron making,) an addition of 8 cwt. of coal 

 being made for healing the air, the diflerence is truly so small as to be alto- 

 gether unworthy of consideration, on taking into account the deteriorated 

 value of the produce. 



- March 1842. per ton. 



Price of Scotch hot blast iron at Hull, (No. 1,) £3 7 6 

 To which add for its general inferiority to 



Yorkshire iron 5 



3 12 6 



Price of Yorkshire cold blast iron at Hull, 

 (No. 1.) • 



Dili'erence in favour of cold blast iron generally I 12 6 

 3 In Mr. Fairbairn's recent experiments, published in the Manchestfr Me- 

 moirs, the diflerence in this respect is very striking : — 

 Each bar being 1 in. square and 4 ft. in. long between supports. 



Breaking weight. Power to 



resist impact. 

 Oldberry cold blast iron .... 4531bs. 822lbs. 



Ohlberry hot do 543 549 



Using the same coal and ironstone, 



Elsecarcold do 446 992 



Mdton hot do 3.53 .538 



W(,rking in the same mineral field in N. Wales, 

 Ponkey cold do. .... 567 992 



Pla,-kynaslon hot do 378 517 



3 M 2 



