OF THALLIUM, INDIUM, AND TIN 37 



osmotic work to be obtained from the dilution of an amalgam, may best 

 be discussed in the light of the further data presented in the next paper. 

 Hence they will be deferred to the conclusion of the monograph. 



In conclusion, it is a pleasure to express our indebtedness to the 

 Carnegie Institution of Washington for the apparatus and materials used 

 in this work. 



SUMMARY. 



The main points of the present research may be summarized as follows : 



1 i ) The potentials between various liquid amalgams of thallium, 

 indium, and tin were investigated at 30 and o. Many precautions were 

 taken against experimental errors. The potentials of the thallium cells 

 are thought to be reliable within o.ooooi volt; those of the indium and 

 tin cells within 0.000005 volt. 



(2) Thallium and indium amalgams gave potentials higher than those 

 calculated from the simple concentration law ; and tin amalgams gave 

 potentials lower than those calculated from the simple concentration law. 



(3) The temperature coefficients of the various cells have been calcu- 

 lated and found to approach the ideal value 0.00366 for a unit potential 

 as infinite dilution is approached. 



(4) The equation of Cady was applied to the results, and found to 

 afford a fairly accurate explanation of the deviations from the concentra- 

 tion law in all three cases. 



(5) The equation of Helmholtz was used for the calculation of the 

 heats of dilution, and was found to account for the changes in the tempera- 

 ture coefficients. 



(6) It was found impossible to obtain satisfactory results with an elec- 

 trolyte containing tin in a quadrivalent condition, either as stannic chlo- 

 ride or as sodic stannate. In this connection it was pointed out that Cady 

 must have had a two-phase amalgam in his tin cell, and that his results 

 with tin were illusory. 



(7) The density of pure indium was determined and found to be 7.28. 



(8) The densities of various liquid amalgams of thallium, indium, and 

 tin were carefully measured and compared with the calculated values. 



SEPTEMBER 1907 TO JANUARY 1909. 



