CONTRIBUTIONS FROM THE JEFFERSON PHYSICAL 

 LABORATORY, HARVARD UNIVERSITY. 



THE ACTION OF MERCURY ON STEEL AT HIGH 

 PRESSURES. 



By P. W. Bridgman. 



Presented by John Trowbridge, November 9, 1910. Received October 28, 1910. 



Under ordinary circumstances steel and mercury are inert with 

 respect to each other, as is shown by the possibility of carrying 

 mercury for indefinite periods of time in steel flasks. But there seems 

 to be a widely spread notion that under higher pressures there may be 

 some action not operative at lower pressures. This possibility is 

 usually ascribed to the extraordinary mobility of the mercury molecule. 

 For instance, every one who has had experience in making joints for 

 pressures of a few atmospheres knows that mercury will easily find its 

 way through holes impervious to water or less viscous fluids. It has 

 therefore been thought probable that under higher pressures the easily 

 moving mercury molecule might be forced through the very pores of 

 the solid metal itself, and that in consequence it might be impossible 

 to hold mercury at all in metal receptacles at high pressures. This 

 view has received its highest confirmation from some often cited 

 experiments of Amagat. Amagat^ has described how in one case 

 mercury was forced by a pressure of 3000 atmospheres in a fine spray 

 through 8 cm. of cast steel, in which no flaw could be afterward 

 detected with the microscope. Amagat explained this effect in the 

 way suggested above by assuming that the mercury was forced by the 

 high pressure through the very intermolecular pores of the solid steel. 

 It is worthy of notice that it was found possible to avoid this difficulty 

 merely by making another apparatus with thicker steel parts. There 

 is also work by Cailletet and Collardeau ^ on the vapor pressure of 

 mercury at high temperatures that seems to demand in explanation 



1 Amagat, Ann. de Chim. et Phys. (6), 29, 87-88 (1893); also Compt. 

 Rend. March 2, 1885. 



a Cailletet, Colardeau and Riviere, Compt. Rend. 130, 1585-1591 (1900). 



