Elements of chemistry : including the applications of the science in the arts . 5)450 90add 32 Or the 50° C. corresponds with the 122° facility of reference a table of the corresponding degrees is given in Appendix II. THE THERMOMETERFig. 13. 45. Darnells pyrometer is a valuable instrument of this kind, of which the indicationsresult from the difference in the expansion by heat of an iron or platinum bar, anda tube of well-baked black-lead ware, in which the bar is contained. The metallicbar a is shorter than the tube, and a short plug of earthenware b is placed in themouth of the tube a
Elements of chemistry : including the applications of the science in the arts . 5)450 90add 32 Or the 50° C. corresponds with the 122° facility of reference a table of the corresponding degrees is given in Appendix II. THE THERMOMETERFig. 13. 45. Darnells pyrometer is a valuable instrument of this kind, of which the indicationsresult from the difference in the expansion by heat of an iron or platinum bar, anda tube of well-baked black-lead ware, in which the bar is contained. The metallicbar a is shorter than the tube, and a short plug of earthenware b is placed in themouth of the tube above the iron bar, and so secured by a strap of platinum foiland a little wedge, that it slides with difficulty in the tube. By the expansion ofthe metallic bar, the plug of earthenware is pushed outwards, and remains in itsnew position after the contraction of the metallic bar on cooling. The expansionof the iron bar thus obtained, is measured by adapting to the instrument an index,c, which traverses a circular scale, before and after the earthenware plug has beenmoved outwards by the expansion of the metallic bar. The degrees marked on thescale are in each instrument compared experimentally with those of the mercurialscale, and the ratio mark
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Keywords: ., bookcentury1800, bookdecade1850, bookpublisherphila, bookyear1853
