22 INTRODUCTION TO GENERAL SCIENCE 



as the boiling point, of water. It has this advantage, how- 

 ever, that zero means a definite thing (namely, the freezing 

 point), and that one hundred is an easier number with which 

 to deal than two hundred and twelve. In foreign countries, 

 and in scientific work everywhere, the Centigrade scale is 

 used, and no doubt it will gradually supplant the Fahrenheit, 

 even for common purposes. 



References : 



1. 1803:129-134. Thermometry. 



a. 1801 : 254. Temperature. 



6. 1801 : 255-258. Thermometers and Thermometer Scales. 



c. 1804 : 251-252. Definition of Temperature. 



d. 1804 : 254-257. Graduation of Thermometers. 



e. 1805 : 292-296. Temperature and Thermometers. 

 /. 1806 : 310-313. Temperature and Thermometers. 

 g. 1807 : 163. Temperature Defined. 



h. 1808 : 206-207. Temperature Defined. 



Experiment 7. The Fixed Points of the Thermometer. 



Apparatus : A thermometer with scale 10 to 225 

 Fahrenheit, a Centigrade thermometer with scale 20 to 

 110, two beakers 100 c.c., ring stand, asbestos mat, 5"X5", 

 lamp for heating. 



Materials : Crushed ice, water, matches. 



a. Put both thermometers in the beaker which contains the 

 ice, and allow them to remain until the mercury ceases to fall. 

 What do the thermometers indicate ? What is the difference 

 between C. and 32 F.? 



6. Put both thermometers in some cool water and heat 

 the beaker over an asbestos mat. Read the thermometers 

 when boiling begins. Which is hotter, the Fahrenheit ther- 

 mometer or the Centigrade thermometer ? 



