The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . surround-ing gas, has been solved by Demarcay, Schusterand Hemsalech, who have proved that practicallyall the air lines of a spectrum may be elim-inated by placing in the discharge circuit aproper amount of inductance. In this mannerthe discharge is prolonged and is made to re-semble that of the arc. This is an especially useful method in ob-serving the discharge in the capillary poriion ofa vacuum tube. The chief difficulty in the nakedprism
The Americana; a universal reference library, comprising the arts and sciences, literature, history, biography, geography, commerce, etc., of the world . surround-ing gas, has been solved by Demarcay, Schusterand Hemsalech, who have proved that practicallyall the air lines of a spectrum may be elim-inated by placing in the discharge circuit aproper amount of inductance. In this mannerthe discharge is prolonged and is made to re-semble that of the arc. This is an especially useful method in ob-serving the discharge in the capillary poriion ofa vacuum tube. The chief difficulty in the nakedprism is that the source, however small, is gen-erally still so large that the successive coloredimages formed by the prism will overlap eachother, leaving the separation incomplete. Toavoid this difficulty a small telescope — calleda collimator — is placed between the prism andthe source as shown in Fig. 4. In the principalfocus of its objective is placed a narrow, straightslit with movable metal jaws. The source isnow placed immediately back of this slit, or theimage of the source is focused upon the slit bymeans of a lens, called the image BZ Fig. 2.— Circuit for spark discharge. Illustrates a typ-ical discharge circuit. T is an induction coil or highvoltage transformer. The primary circuit is operatedby a battery, B, or some source of alternating current. The electrodes are connected in series withan inductance I, and in parallel with a capacityC. Concerning the temperature of the spark verylittle is known. It has been generally assumedto be very much higher than that of the electricarc: but there is no direct evidence for this viewand there is much indirect evidence against it. 3. Separation of Radiations.— Let us sup-pose that we now have before us one of theabove-mentioned sources whose spectrum it is
Size: 2018px × 1238px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, bookdecade1900, bookidamericanaunivers14newy
