. Transactions . d to the fluid state, the tempera-ture remains constant for a brief period, the duration of which de-pends on the amount of material operated upon and its latent heat»)f fusion, the result being that the spot of light from the galvanom-eter will l)e arrested, and the position on the scale at which it stopsmarks the temperature to be determined. A detailed drawing of a more elaborate form of this appliance isgiven in Plate I. The appliance consists, as is shown in this plate, of a camera about5 feefr long, in which a galvanometer may be placed in either of twopositions accordin
. Transactions . d to the fluid state, the tempera-ture remains constant for a brief period, the duration of which de-pends on the amount of material operated upon and its latent heat»)f fusion, the result being that the spot of light from the galvanom-eter will l)e arrested, and the position on the scale at which it stopsmarks the temperature to be determined. A detailed drawing of a more elaborate form of this appliance isgiven in Plate I. The appliance consists, as is shown in this plate, of a camera about5 feefr long, in which a galvanometer may be placed in either of twopositions according to the range of temperature to be observed. Thiscamera has three doors, and is made separate from the portion of theapparatus which contains the moving photographic plate, C. Thetwo parts are connected by a flexible leather bellows junction, G,the object being to enable the plane of the sensitized plate to be ad-justed at right angles to the rays of light from the galvanometer RECENT ADVANCES IX PYROMETRY. 421. 422 RECENT ADVANCES IN PYROMETRY. mirrors, F and M. Inside the camera is a focussing-tube, T, con-taining a lens, L, which receives the light from the mirror, H, andtransmits it to the mirrors, F and M. One of these mirrors, M,is movable, and is carried by the coil of the galvanometer, whilethe other, F, is carried upon an adjustable arm fixed to the supportsof the galvanometer, its function being to send a ray of light fromthe mirror, H, to the slit, A B, and thus to trace a datum line as thephotographic plate travels upward. The temperature is recorded bythe variations in the position of the spot of light received from themirror, M. There is a screen, S,, to cut off light reflected from thebrass work of the galvanometer. The end of the tube, T, is pro-vided with an adjustable brass slit, O, by means of which the widthof the photographic traces on the plate may be varied. The mirror,H, is mounted on a block, which can be adjusted so that externallight may be received
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
