The composition of every cell is different from that of the material i — Sodium

"SODIUM. Of all the spectral reactions that of sodium is the most sensitive. The yellow line Naα, the only one which is shown in the sodium spectrum coincides with Fraunhofers line D and is characterized by its peculiarly sharp boundary and its extraordinary brilliancy. If the temperature of the flame is very high and the quantity of the substance used very great, traces of a continuous spectrum are seen in the immediate neighborhood of the line."

"Black... set himself the problem of accurately determining the differences in composition between burnt (or caustic) and unburnt (or mild) alkali, and he solved the problem most successfully. He showed that the properties of mild alkalis differ from those of caustic alkalis, because the composition of the former differs from that of the latter; and he showed exactly wherein this difference of composition consists, viz. in the possession or non-possession of fixed air. Strange we may say that this discovery did not induce Black to prosecute the study of caustic alkalis: surely he would have anticipated Davy, and have been known as the discoverer of and sodium."

"Lines of other substances, in themselves very weak, lying near it appear still weak and will, therefore, often first be visible after the sodium reaction has begun to disappear."

"Study of the conduction of electricity in liquids became possible at the beginning of the nineteenth century, following the discovery of the electrolytic cell by Volta in 1800, which provided the first continuous source of electric current. It was soon discovered that the conduction of electricity by solutions is accompanied by chemical reactions at the electrodes which serve to conduct the current into and out of the solution. Nicholson and Carlisle demonstrated the decomposition of water into and oxygen by a current in 1801. Davys discovery of sodium and metals by electrolysis of moist soda and [caustic] potash was a striking example of the novelty of electrochemical decomposition. Many of the phenomena of were already known when Michael Faraday began his researches."

"We will now consider more closely the characteristics of the several spectra, the knowledge of which is of importance from a practical standpoint, and indicate the advantage which the chemical analytical method founded upon it furnishes."

"The first difficulty that faced us was the identification of the forms seen on focusing the sight on gases. We could only proceed tentatively. Thus, a very common form in the air had a sort of dumb-bell shape... we examined this, comparing our rough sketches, and counted its atoms; these, divided by 18—the number of ultimate atoms in —gave us 23.22 as atomic weight, and this offered the presumption that it was sodium. We then took various substances—common salt, etc.—in which we knew sodium was present, and found the dumb-bell form in all. In other cases, we took small fragments of metals, as iron, tin, , silver, gold; in others, again, pieces of ore, mineral waters, etc... In all, 57 chemical elements were examined, out of the 78 recognized by modern chemistry. In addition to these, we found 3 chemical waifs: an unrecognized stranger between and which we named occultum, for purposes of reference, and 2 varieties of one element, which we named kalon and meta-kalon, between and ... Thus we have tabulated in all 65 chemical elements, or chemical atoms, completing three of Sir William Crookes s, sufficient for some amount of generalization."