480 M. Fromme on the Changes produced, in the Molecular 



mining the densities of the pieces, they were placed in nitric 

 acid to which a little hydrochloric acid had been added, and 

 were allowed to be acted upon to a certain extent; then the 

 density was determined again ; they were further acted upon 

 by the acid; and so on. 



The action took place, on the whole, very regularly: the 

 bars retained their cylindrical form and smooth surface; two 

 of the pieces showed channels, but of very small depth. 



The hydrostatic balance was employed for the determination 

 of density, except that the first ten observations with the 

 bar (b) were made with the previously mentioned pycnometer. 

 Table II. contains the results of the determination of density, 

 together with the absolute weights of the pieces. 



Table II. 



No. 



a 





b 





c 





d 





t 





of 



obs. 











































1. 



m. 



8. 



m. 



8. 



m. 



8. 



m. 



8. 



m. 



8. 



6-635 



7-735 



6-480 



7-714 



6-328 



7-715 



6-338 



7-727 



4-931 



7-795 



2. 



624 



734 



462 



703 



245 



704 



248 



718 



856 



790 



3. 



610 



731 



452 



754 



204 



706 



122 



718 



777 



789 



4. 



596 



733 



402 



754 



142 



706 



005 



713 



670 



794 



5, 



576 



729 



360 



760 



051 



704 



5-892 



716 



577 



793 



6. 



538 



731 



321 



758 



5-946 



698 



784 



716 



508 



792 



7. 



495 



731 



282 



759 



803 



702 



625 



723 



437 



798 



8. 



474 



731 



229 



757 



332 



700 



531 



718 



343 



791 



9. 



424 



730 



188 



753 



181 



704 



377 



716 



270 



793 



10. 



349 



732 



154 



758 



4-868 



696 



278 



715 



177 



789 



11. 



296 



733 



115 



745 



594 



708 



145 



714 



103 



788 



12. 



241 



731 



072 



747 



297 



705 



026 



704 



3-999 



791 



13. 



080 



728 



016 



745 



060 



701 



4-909 



708 



861 



790 



14. 



018 



735 



5-974 



743 



3-778 



697 



772 



704 



771 



787 



15. 



5-754 



730 



916 



747 



535 



698 



607 



710 



656 



783 



16. 



587 



735 



857 



739 



202 



710 



391 



710 



590 



786 



17. 



129 



725 



813 



733 



2-898 



693 



201 



714 



507 



781 



18. 



4-630 



728 



756 



735 







3-973 



705 



395 



789 



19. 



177 



731 



696 



736 







759 



705 



318 



792 



20. 



3-645 



735 



649 



739 







559 



700 



216 



795 



21. 



038 



734 



590 



737 







388 



720 



116 



792 



22. 



2-747 



733 



527 



736 







237 



715 



2-987 



794 



23. 









484 



737 







049 



715 



880 



780 



24. 









435 



736 







2-882 



708 







25. 









378 



740 







737 



705 







26. 









321 



737 















27. 









247 



736 















28. 



. 







176 



735 















29. 









083 



736 















30. 









4-998 



734 















31. 









660 



735 















The density of the bar (a) thus remained nearly constant 

 throughout the process of dissolving away. It was almost 



