342 



Appendix. 



Thermometric scales. — On the Centigrade (C.) scale 

 the freezing point of water is made zero, and the 

 boiling point 100 ; on the Fahrenheit (F.) scale the 

 zero is placed 32 degrees below the congealing point 

 of water, the boiling point of which becomes, conee- 

 quently, 212. 



The degrees of one scale are easily converted into those 

 of another if their relations be remembered — namely : 

 180 (F.), 100 (C.) : that is, 18 to 10, or o'to 5. 



Formul<B for the Conoersion of Degrees of one Ther- 

 mometric Scale into those of another : 



F = Fahrenheit; C = Centigrade ; D = The observed degree. 



If above the freezing point of water (32° F.; 0° C), 



F into C, . . . (D — 32) -- 9 X 5. 



C into F, . . . D H- 5 X 9 + 32. 



If below freezing, but above 0° F (— 17°-77 C), 



F into C, . . — (32 — D) -H- 9 X 5. 



C into F, . . . 32 — (D ^ 5 X 9. 



If below 0° F (— 17° '77 C), 



FintoC, . . . — (D + 32)-^9X5. 



CintoF, . . . — (D-r-5X9) — 32. 



Equivalents on the Centegrade and Fahrenheit 

 scales : 



