Pyrometry: A Practical Treatise on the Measurement of High Temperatures

=General Principles.=—Seebeck, in 1822, made the discovery that when a junction of two dissimilar metals is heated an electromotive force is set up at the junction, which gives...

=General Principles.=—It is a common experience that the heat radiated by a substance increases as its temperature rises; and it would obviously be an advantage if the temperatu...

=General Principles.=—When a pure metal is heated, its resistance to electricity increases progressively with the temperature. Certain alloys, on the other hand, show a practica...

=General Principles.=—When a solid is heated to 450° C., it commences to send out luminous radiations and appears a dull-red colour in a darkened room. As the temperature rises,...

=Expansion and Contraction Pyrometers.=—Most substances, on heating, exhibit an increase in size, and on cooling return to the original dimensions. If, however, a chemical alter...

=The Absolute or Thermodynamic Scale of Temperatures.=—All practical instruments for measuring temperatures are based on some progressive physical change on the part of a substa...

=General Principles.=—If a piece of hot metal, of known weight and specific heat, be dropped into a known weight of water at a temperature _t_{1}_, which rises to _t_{2}_ in con...

The term “pyrometer”—formerly applied to instruments designed to measure the expansion of solids—is now used to describe any device for determining temperatures beyond the upper...

=General Principles.=—If a number of solids, possessing progressive melting points, be placed in a furnace and afterwards withdrawn, some may be observed to have undergone fusio...