00800 | .001440 |
|Lead | 32 to 212 | .001505 | .002709 |
|Mercury | 32 to 212 | .009984[5] | .017971 |
|Platinum | 104 | .000499 | .000899 |
|Limestone | 32 to 212 | .000139 | .000251 |
|Silver | 104 | .001067 | .001921 |
|Steel (Bessemer | | | |
|rolled, hard) | 0 to 212 | .00056 | .00101 |
|Steel (Bessemer | | | |
|rolled, soft) | 0 to 212 | .00063 | .00117 |
|Steel (cast, | | | |
|French) | 104 | .000734 | .001322 |
|Steel (cast | | | |
|annealed, English) | 104 | .000608 | .001095 |
+-------------------+--------------+----------------+----------------+

High Temperature Measurements--The temperatures to be dealt with in
steam-boiler practice range from those of ordinary air and steam to the
temperatures of burning fuel. The gases of combustion, originally at the
temperature of the furnace, cool as they pass through each successive
bank of tubes in the boiler, to nearly the temperature of the steam,
resulting in a wide range of temperatures through which definite
measurements are sometimes required.

Of the different methods devised for ascertaining these temperatures,
some of the most important are as follows:

1st. Mercurial pyrometers for temperatures up to 1000 degrees
Fahrenheit.

2nd. Expansion pyrometers for temperatures up to 1500 degrees
Fahrenheit.

3rd. Calorimetry for temperatures up to 2000 degrees Fahrenheit.

4th. Thermo-electric pyrometers for temperatures up to 2900
degrees Fahrenheit.

5th. Melting points of metal which flow at various temperatures
up to the melting point of platinum 3227 degrees Fahrenheit.

6th. Radiation pyrometers for temperatures up to 3600 degrees
Fahrenheit.

7th. Optical pyrometers capable of measuring temperatures up to
12,600 degrees Fahrenheit.[6] For ordinary boiler practice
however, their range is 1600 to 3600 degrees Fahrenheit.

[Illustration: 228 Horse-power Babcock & Wilcox Boiler, Installed at the
Wentworth Institute, Boston, Mass.]

Table 7 giv