191 



THE CIVIL EXGINEER AND ARCHITECTS JOURNAL. 



[June, 



EXPERIMENTS ON CAST IRON. 



A Series of Expkbiments on the Cojipabative Stbenoth of dif- 

 ferent Kindx of Cast Ikon, jn their simple state as cast from the 

 Pig, and also in their compounded state as Mixtures; made under 

 the directions of Robert Stephenson, Esq., with a inew to the 

 selection of the most suitable for the various purposes required in the 

 construction of the High Level Bridge. 



The bars were all cast from the same model, and as near as pos- 

 sible one inch square. They were all weij^hted on the centre of 

 their length by a machine made expressly for testing the same, 

 having a fixed distance of bearing of e.xactly three feet. 



The experiments were conducted at Gateshead Iron Works 

 between the months of September IStG, and February 1817. 



The bars were all cast as near as practicable one inch square, 

 those which were found to be defective in this respect were rejected 

 previous to testing. If, however, upon the breaking of the bars 

 and measuring across the section of fracture, any dilference from 

 the true size was discovered, it was noted in the remarks. When 

 the diiFerence was not appreciable by measurement it is stated 

 "rather full in size;" when it was, the dimensions are given as 

 ^ih square, 1^ wide, by I3W deep, and when this occurs, the 

 breaking weights are reduced to one inch square. 



Note.— From this point +, whenever it occurs, the weighting was conlirued by small 

 shot, 7 pounds at a time, run from a cup containing that weigh!, until the bar broice, 

 when if any remained in the cup it was weighed baclt. — B indicates the breaking weight. 



HOT-BLAST IRON. 



I. Scotch— Hot Blast. 



Weight applied 



in lbs. 

 ^ 406 

 518 



1. Metal mild and open in the grain at 

 the centre of the bar. 



r 



2. Fracture more close than No. 1. 



3. Close and uniform ■{ 



I 



630 



086 



B 742 



406 

 518 

 630 

 686 

 + 742 

 ^B 779 



406 

 518 

 630 

 686 

 + 742 

 B804 



Deflection. 



•265 

 •36 

 •44 

 •51 



•31 



•39 



•495 



•535 



•59 



•655 



•315 



•41 



•54 



•01 

 •65 

 •74 



Set. 



Mean breaking weight of the three bars, 775 lb. 



II. Coltnets, No. 3.— Hot Blast. 

 406 



1 . Metal clear and even in texture ; open ; 

 rather dark in colour. 



2. Metal as No. 1. 



r 



3. Metal as above. This bar exceeded the 

 size by -^ in depth. 



406 

 518 

 630 

 058 

 680 

 714 

 + 742 

 15 809 

 Mean breaking weight of the three bars, 1 



III Langloan, No. 3. — Hoi Blast. 



{406 

 518 

 030 

 B728 



•325 



•43 



•56 



•59 



•63 



■82 



•35 



■475 



■02 



■665 



■74 



•30 



•395 



•51 



■54 



•575 



•607 



•045 



■065 



•027 

 ■04 6 

 •07 



•04 



•07 

 ■10 



•02 

 •03 

 •052 



89 lb. 



•33 

 •44 



•575 

 •66 



•025 



■04 



•07 



