. The London, Edinburgh and Dublin philosophical magazine and journal of science . 180 to 200 centimetres in transformers are connected to a battery of ten thousandcells ; and can afford voltages from twenty thousand to threemillion. Various methods of measurement were tried. Onaccount of the great tension all galvanometric and electro-metric means had to be abandoned; and what is known as theelectric thermometer was finally adopted. This consists, as iswell known, of a hermetically closed glass tube provided witha manometer-gauge. The electrical discharge passes throughthe tube b
. The London, Edinburgh and Dublin philosophical magazine and journal of science . 180 to 200 centimetres in transformers are connected to a battery of ten thousandcells ; and can afford voltages from twenty thousand to threemillion. Various methods of measurement were tried. Onaccount of the great tension all galvanometric and electro-metric means had to be abandoned; and what is known as theelectric thermometer was finally adopted. This consists, as iswell known, of a hermetically closed glass tube provided witha manometer-gauge. The electrical discharge passes throughthe tube by means of a fine wire, or by a spark-gap. Theterm electrical thermometer is a misleading one : for, as weshall show, the quick movement of the manometer-gauge isnot due to heat. At first we passed the discharge through very fine gauge, which consisted of a bent glass tube containing anindex of bichromate of potash, rose suddenly at each dischargeand returned approximately to the zero-point. When, how-ever, the wire had been heated by repeated discharges, the Fiar. index showed a slow rise in temperature. Even when theterminals in the glass tube were connected by a fine wire avery strong electrostatic field was created in the tube. Thisis shown in an interesting manner by fig. 1. This photograph Explosive Effect of Electrical Discharges. 281 was obtained by stretching a fine wire over a photographicfilm ami sending a single discharge through the wire, therebeing no spark-gap in the circuit. The fine wire vibratedduring the discharge ; and when the negative thus obtainedwas closely examined, subsidiary vibrations were shown bymany black lines approximately parallel to each other. Theselines were apparently caused by the heat of the dischargemelting the gelatine where the wire came in close contactwith the film. The electrostatic field about the wire isexhibited by a fern-like discharge at right angles to the were soon convinced that heat played a subordinate
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectscience, bookyear1840
