Density of Fluid Bis mu tli , 



299 



the equilibrium-line. This diagram shows, up to the plastic 

 point (where loss of mass commences), the gradual change of 

 volume at progressive intervals of time. 



Fig. 2. 

 Experiment No. 23, on Iron. 



6 inin . 



Weight of ball and immersed part of stalk 132 oz. 



Specific gravity of ball and immersed part of stalk 6 - 95 



Maximum sinking effect 2 oz. 



Maximum floating effect 11 oz. 



.„ . fa . , . 6-95x130-0 _ a . RA 

 Specific gravity of fluid iron = ^-^ ... — o »4 



Specific gravity of plastic metal == — -— — -± ... =6*33 



4-inch ball of No. 4 foundry iron (Cleveland). Eun with very hot metal. 

 Immersed in No. 4 foundry iron. 



The diagram read from left to right should represent the 

 change from liquid to solid ; and this is quite in accordance 

 with other observations on cast iron*. 



According to these experiments, iron expands rapidly (as 

 much as 6 per cent.) in cooling from the liquid to the plastic 

 state, and then contracts 7 per cent, to solidity ; whereas bis- 

 muth appears to expand in cooling from the liquid to the solid 

 state about 2*35 per cent. 



* Journ. Iron and Steel Inst. No. II. 1879, and No. I. 1880. 



