. The railroad and engineering journal . g coal is obtained in the current; and for this rea-son electricians have labored for years to get electricityfrom coal direct. Their starting point has been the dis-covery of Seebeck, that if the junctions of two metals bekept at different temperatures, a current will result; iffor instance, a piece of copper ii-, hg. 20) be placed as Vol. LXl. No. ENGINEERING JOURNAL. 556 shown on a block of bismuth, a b, and one junction, *, beheated while the other a, be kept cool, a small currentwill pass, as evidenced by the deflection of a pivoted mag-net pl
. The railroad and engineering journal . g coal is obtained in the current; and for this rea-son electricians have labored for years to get electricityfrom coal direct. Their starting point has been the dis-covery of Seebeck, that if the junctions of two metals bekept at different temperatures, a current will result; iffor instance, a piece of copper ii-, hg. 20) be placed as Vol. LXl. No. ENGINEERING JOURNAL. 556 shown on a block of bismuth, a b, and one junction, *, beheated while the other a, be kept cool, a small currentwill pass, as evidenced by the deflection of a pivoted mag-net placed near. All the known metals have been tried,and numberless alloys, in the endeavor to produce a celloperated by heat alone, able to inexpensively generatecurrents sufficiently large to be of practical use for work-ing lights and motors. One of the largest of these t/iermo-eUclru cells is Clanionds, in which the junctions areheated, of large blocks of alloy with sheets of iron. Theproducts of combustion pass through flues which bring. Fig 20. them into contact witli one series of junctions, the otherjunctions being cooled by air. It is stated that, with thisapparatus, a current has been generated strong enough tosupport an electric light of considerable power. A curiousinvention in this line is that of M. Brard, called an elec-tro-generative brick. The brick is made of preparedcarbon, separated from nitrate of potash by a sheet ofasbestos. A strip of brass is embedded in each, and thewhole is enveloped in asbestos paper, the brass strips pro-truding. If the brick be now put into a hot fire, wiresbeing attached to the two brass strips, a current, it is said,strong enough to ring a bell, will circulate in the wire, andcontinue for about two hours. Though the act of producing electricity from heat directcannot be said to have yet reached the practical stage,yet it is probably the method of the future ; and thoughinvestigators are now groping in the dark, progress issurely thoug
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
