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Thermometer Bulbs Practically: Contributions to Metrology of Sciences and adustries.—Many sciences and industries have given metrology their best thoughts and labors. Chemistry, for example, opened up new chapters in the science of the refractory metals, developing iridium and platinum of purity requisite for constructing international fundamental standards of measurement. Chemistry in conjunction with metallurgy also produced the remarkable nickel-steel alloy Invar (q.v.), having practically a zero temperature coefficient of expansion; the alloy Man-ganin, free from temperature coefficient for electrical resistance; Jena glass, a material for measuring flasks and thermometer bulbs practically bulbs which practically eliminates temperature disturbances.
One of the most popular ways of growing bulbs—snowdrops, daffodils and crocuses, in particular—is to naturalize them in drifts so they spread at will. This is usually done in grass, but those bulbs preferring shady woodland conditions can be naturalized in soil under trees and shrubs. It is also possible to establish bulbs beneath a planting of ground cover like scrambling ivies.
Ordinarily a solid crystal warms up and expands as it is heated until at a characteristic temperature it melts and is transformed into its liquid phase. During the transformation from one phase to the other, if the process is slow, no change in temperature occurs. In Black's words, heat is "absorbed and concealed" during the process "so as not to be discoverable by the application of a thermometer bulbs practically." Although the mean interparticle distance is changed, the vehemence of the particle motions is not, and therefore there can be no effect on a thermometer bulbs practically in contact with the melting crystal. |
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