V 



2 ELECTROCHEMICAL INVESTIGATION OF LIQUID AMALGAMS 



This monograph embodies the results of the further investigation of 

 amalgam cells, containing not only the two metals already mentioned, but 

 also thallium, indium, tin, lead, copper, and lithium. The first section of 

 the monograph deals with thallium, indium, and tin. These metals are 

 especially interesting because they are respectively univalent, trivalent, 

 and (under some conditions) quadrivalent. Thallium is, moreover, inter- 

 esting in its chemical behavior, having in common with the alkali-metals 

 a soluble hydroxide, carbonate, and sulphate, while on the other hand 

 resembling lead in the possession of an insoluble chromate and sulphide, 

 and a slightly soluble chloride. Indium is the only trivalent metal that 

 forms satisfactory amalgams for the present purpose. 1 



The effort was made to attain precision sufficient to afford an adequate 

 basis for the desired theoretical considerations. No attempt was made to 

 attain the greatest conceivable precision, because such an attempt would 

 have defeated the object of the investigation, by so limiting the variety 

 of results obtainable in the limited time as to have restricted their gen- 

 eralization. 



1 An almost complete historical review may be found in the monograph of Rich- 

 ards and Forbes (Publication of Carnegie Institution of Washington, No. 56; 

 Zeitschrift fur phys. Chem., 58, 683 [1907]). A paper by J. Regnauld (Compt. 

 Rend,, 53, 533 [1861]) on the heat of amalgamation of the metals was overlooked 

 in this review, and the date of Helmholtz's publication (Monatsbericht d. kgl. pr. 

 Akad., Berlin, 1877, p. 713) was accidentally given as 1882 instead of 1877. The 

 reference to Lindeck's work is Wied. Ann., 35, 311, 1888. Mention should be made 

 of a mathematical paper by Trevor on the " Electromotive Force of Concentration 

 Cells" (Zeitschr. Elektrochem., 11, 681 [1905]). While this paper contains inter- 

 esting features, experimental verification of the equation deduced therein is not 

 possible at present. In a recent paper published after most of the work embodied 

 in this monograph had been completed, Carhart discusses the Helmholtz equation, 

 as applied to amalgam cells. (Phys. Rev., March, 1908). In a yet more recent 

 paper by Hulett and De Lury, published after the conclusion of the present work, 

 the work of Richards and Forbes is in part repeated and extended to more dilute 

 solutions. In so far as the two investigations overlap, they confirm one another 

 (J. Am. Chem. Soc., 30, 1812 [1908]). Another theoretical paper, by van Laar 

 (Arch. Neerl. d. Sci. ex. et nat. [n] vm, 296), should perhaps be mentioned. 



