SOLID HYDROGEN. 261 



It will be noted that the density of gaseous hydrogen at 3,000 atmos- 

 pheres is actually greater than the maximum density of the liquid 

 state, but neither in the case of nitrogen nor oxygen does the density 

 at the same pressure reach the fluid density. Amagat's limiting value 

 for ox} T gen under 4,000 atmospheres would, however, be almost iden- 

 tical with mine. 



During the course of my inquiries sufficient data have been accumu- 

 lated to construct Waterston formula 3 giving the approximate densities 

 of liquid hydrogen, nitrogen, and oxygen in each case through a wide 

 range of temperature. The equation for each substance is given in the 



following table: 



Liquid atomic volumes. 



Hydrogen = 23. 3 - 8. 64 log (32°-/) 

 Nitrogen = 30. - 11. 00 log (127°— t ) 

 Oxygen = 32. 6 - 10. 22 log (155°— t ) 



Absolute Observed at 

 zero, melting point. 



1. Atomic volume of hvdrogem 



„ A . . , f r , h=10.3 11-7 



2. Atomic volume oi hydrogen J 



3. Atomic volume of nitrogen =12. 8 13. 1 



4. Atomic volume of oxygen =10.20 12.6 



From these formula? we find the respective hypothetical atomic vol- 

 umes of hydrogen, nitrogen, and oxygen at the absolute zero to be 

 10.3, 12.8, and 10.2. My observed minimum fluid values were 11.7, 

 13.1, and 12.6. The coefficients of expansion of the liquids, taken in 

 the same order at their respective boiling points, are 0.024, 0.0056, and 

 0.0046. Thus liquid hydrogen had a coefficient of expansion five times 

 greater than that of liquid oxygen. Further inquiry will enable the 

 constants in these equations to be determined with greater accuracy. 

 In the meantime, however, they give us general ideas of the order of 

 magnitude of the quantities involved. 



I have to thank Mr. Robert Lennox for efficient aid in the arrange- 

 ment and execution of the difficult experiments you have witnessed. 

 Mr. Heath has also heartily assisted in the preparations. 



