Clark and Weston standard cells . ts electromotive properties. Suchmaterials can not, therefore, be directly employed if the highestaccuracy of reproduction is sought. A considerable number ofsamples of mercurous sulphate was prepared by the followingmethods: (a) By electrolysis, old apparatus. (b) By electrolysis, new apparatus. (c) By the action of fuming sulphuric acid on mercury. (d) By the reaction between sulphuric acid and mercurous nitrate. i6 Bulletin of the Bureau of Standards. [ Vol. 4, No. i. (e) By the action of a dilute solution of nitric acid in sulphuricacid on mercury. (f) By
Clark and Weston standard cells . ts electromotive properties. Suchmaterials can not, therefore, be directly employed if the highestaccuracy of reproduction is sought. A considerable number ofsamples of mercurous sulphate was prepared by the followingmethods: (a) By electrolysis, old apparatus. (b) By electrolysis, new apparatus. (c) By the action of fuming sulphuric acid on mercury. (d) By the reaction between sulphuric acid and mercurous nitrate. i6 Bulletin of the Bureau of Standards. [ Vol. 4, No. i. (e) By the action of a dilute solution of nitric acid in sulphuricacid on mercury. (f) By the reduction of mercuric sulphate by mercury. (g) By the reduction of mercuric sulphate by sulphurous acid.(It) By the recrystallization of commercial mercurous sulphate from sulphuric acid. (z, k) /, m, n) By digestion of commercial mercurous sulphatewith sulphuric acid. All the samples were prepared in subdued light and preserved inthe dark, to protect them from the action of light. Even diffuseddaylight soon darkens the SULPHURICACID MERCURY MERCURY Fig. 1.—Apparatus for Electrolytic Preparation of Mercurous Sulphate (1904). (a) By electrolysis, old apparatus.—In 1904 an electrolytic methodof preparation was developed by one of the authors,35 and also inde-pendently by Carhart and Hulett,36 the mercurous sulphate beingformed by the passage of a current at the surface of a mercury anodein sulphuric acid. Preliminary experiments, based on the reversi-bility of the Clark and Weston standard cells, as shown by the slightpolarization with weak inverse currents, were made with cadmiumsulphate solutions. Without stirring a crust of yellow basic mercu- 35 Wolff: Trans. Amer. Electrochem. Soc, 5, p. 49; , 5, p. 59; !904. Wolff. IWaters. \ Clark and Weston Standard Cells. 17 rous and mercuric sulphate was formed and the solution gave a verystrong mercuric reaction, while with an acidified solution a beautifulcrystalline product was obtained. The anode mercury w
Size: 1698px × 1472px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1900, bookdecade1900, booksubjectcondensedmatter
