JJeasur'nii/ the Lateral Contraction of Tie-bars. 423 



The si)eciinens were not annealed, and all the above were 

 approximately one inch in diameter exce])t in the cases noted 

 in the table. 



Cast Iron. — Two sets of cast iron s})ecimens were carefully 

 cast in a vertical position. The first was from a mixture of 

 about equal parts of No. 1 Govan, No. 2 Govan, and Heavy 

 Sera}), and the second from 3 parts Redcar Middlesborough, 

 and one part Scrap. 



The material was therefore in each case such as might be 

 used for engine and machine castings. 



The specimens were brought to a state of ease by continued 

 application and removal of load until permanent set was 

 completely eliminated. 



The values given in the following table are those obtained 

 from the elastic state of the bar, that is, the strains do not 

 include permanent set. 



Table III.— Cast Iron. 



I Specimen. 



Strains per | ton of Load. 

 Diameter. 



Young's 

 Modulus. 



Eatio, 



a * 



! 



! Tensile. 



Lateral. 



1st Series. 

 iS^o.l 

 Kg. 2 

 yo. 3 



•752 -000,1552 



1-025 -000,0904 



■752 i -000,1556 



•000,0374 

 •000,020(i 

 •000,0420 



16-25 xlO« 



15^01 



16^21 



•241 

 •228 

 •270 



2nd Series. 

 yo. 1 



yo. 2 

 yo. 3 



-997 ' -000,0877 

 -990 -000,0947 

 •993 -000,0900 



•000,0223 

 •000,0245 

 •000,0220 



16-36 

 15-37 

 16^07 



•254 

 •259 

 •244 



A long series of observations was made for the purpose of 

 determining whether there was any permanent set in the 

 lateral strain. Readings were taken for loads varying by 

 O'l of a ton up to O'O ton on a C.I. bar approximately 

 1 inch in diameter. The readings were in -^^ of an inch, 

 and an estimation of yL of these was made. The total mag- 

 nification was 2700. The bar had not been previously loaded, 

 and it appeared to be perfectly elastic as regards lateral 

 strain. On increasing the load up to 1*0 ton, however, 

 there appeared to be a small amount of permanent set, and 

 between I'O and 1*5 tons the set was very marked. It 

 increased in amount up to 3 tons, which was the limit of 

 load applied. 



