6 CONTENTS. 
Page. 
Chapter II.— The calibration of electrical pyrometers by the aid of fixed 
thermal data 84 
Explanation 84 
Apparatus for low boiling points (100° to 500°) 84 
Original forms of boiling tubes 84 
Perfected forms of boiling tubes 86 
Boiling-point tubes for pressure work 88 
Dr. Gibbs's ring burner 90 
Apparatus for high boiling points 90 
Original forms of boiling-point crucible 90 
Perfected forms of boiling-point crucible 91 
Insulators 95 
Method of measurement 97 
Thermo-element 97 
Standards of electromotive force 99 
Method of computation 103 
Experimental results 104 
Exploration for constancy of temperature ; water, aniline 104 
Exploration for constancy of temperature, mercury 105 
Exploration for constancy of temperature, sulphur 107 
Exploration for constancy of temperature, zinc 108 
Practical calibration , 110 
Investigation of data - 110 
Discussion of data 114 
Time- variation of thermo-electric data 116 
Duration of continued ebullition, constant high temperature 116 
Duration of continued ebullition, constant low temperature 116 
Available substances for boiling points 119 
Points of volatilization 121 
Subsidiary data : antimony; bismuth; cadmium 122 
Thermo-electric datum for the melting point of platinum 124 
Chapter III. —Certain pyro-electric properties of the alloys of platinum 126 
Explanation 126 
Fusion and mechanical treatment of the alloys 128 
Fusion and rolling 128 
Preliminary data, density 128 
Preliminary data, electrical resistance of rods 131 
Experimental data 133 
Further mechanical treatment ; resistance of wires 133 
Thermo-electrics of wires 135 
Temperature coefficient 139 
General digest 143 
Discussion and inferences 144 
Earlier results 144 
Resistance and density 145 
Resistance and thermo-electrics 146 
Electrical tests for purity 146 
Electrical resistance and temperature coefficient 149 
Other relevant results 157 
General remarks 161 
Chapter IV. — The calibration of electrical pyrometers by direct comparison 
with the air thermometer 165 
Displacement methods of thermometry 165 
Constant volume thermometers 167 
(660) 
