A text-book on chemistryFor the use of schools and colleges . d partly inside with tin-foil, a cascade of elec-tric light will flow over on the air-pump plate. If the discharge take place into a space more rarefiedthan the ordinary receiver, the luminous portion is ob-served to be stratified, or crossed by dark bands. Fig. 158 represents hermetically-sealed glass tubesinto which platinum wires have been fused, and inwhich the rarefaction is progressively more rarefaction is produced by filling the tubes withdry carbonic acid gas, and at the same time puttingpieces of caustic potass
A text-book on chemistryFor the use of schools and colleges . d partly inside with tin-foil, a cascade of elec-tric light will flow over on the air-pump plate. If the discharge take place into a space more rarefiedthan the ordinary receiver, the luminous portion is ob-served to be stratified, or crossed by dark bands. Fig. 158 represents hermetically-sealed glass tubesinto which platinum wires have been fused, and inwhich the rarefaction is progressively more rarefaction is produced by filling the tubes withdry carbonic acid gas, and at the same time puttingpieces of caustic potassa, P P PP, into them. Thebands become wider and change their shape, until, whena perfect void is obtained, they disappear. Materialparticles seem to be necessary to the transfer of thecurrent, as in the case of the Voltaic arc. By inclosinga variety of substances in such tubes beautiful effects Describe KuhmkorfTs induction coil. What length of spark maybe obtained? How may auroral light be produced? What areGeisslers tubes ? GEISSLER7S TUBES. Fig. 15S. 183. of color may be obtained. These are called Geisslerstubes. THERMO-ELECTRICITY. If we take a bar of antimony, a, Fig. 159, and one ofbismuth, 6, and, having soldered them end Fig. end at c, pass a feeble current throughthem in a direction from the antimony tothe bismuth, the temperature of the com-pound bar rises, but if the current pass inthe opposite direction, cold is fixing thermometers into the substanceof the bars these facts may be verified; andin the latter case, when water is placed in ^—=*-a depression made for it in the bar, and the reductionof temperature slightly aided, it may be frozen by thecurrent. The same compound bar of bismuth and antimony,having its extremities connected together by a wire,whenever heat is applied to the junction an electric cur-How may an electric current produce heat and cold ? How is anelectric current produced by the apparatus Fig. 159?
Size: 1694px × 1476px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookde, booksubjectchemistry, booksubjectphysics
