Miscellaneous Tables, Figures and Notes. 131 



4. Thcrmomster Scales. 



Fahrenheit.— The freezing-point is taken as the 32d. degree of 

 the scale, and 180 degrees are made between that and the boilings 

 point, which therefore becomes 212°. 



Centigrade or Celsius.— The freezing-point of water is taken as 

 zaro, and boiling-point as 100°. 



Reaumur.— The freezing-point of water is taken as zero, the 

 boiling-point as 80°. 



A degree Centigrade is therefore greater than a degree of 

 Fahrenheit as nine is greater than five ; and a degree of Reau- 

 mur is greater, as nine is greater than four. 



To reduce Fahrenheit degrees to Centigrade, subtract 32 from 

 the given degree of Fahrenheit and multiply the remainder by 5 

 and divide it by 9: (F.°— 32) f 



To reduce Centigrade to Fahrenheit, multiply the given degree 

 of Centigrade by 9 and divide the product by 5, then to the quo- 

 tient add 32: (fC.°-|-32). 



To reduce Fahrenheit to Reaumur, subtract 32 from the given 

 degree of Fahrenheit and multiply the remainder by 4 and divide 

 by 9: (F.°— 32)|. 



To reduce Reaumur to Fahrenheit, multiply the given degree of 

 Reaumur by 9 and divide by 4, then add 32 : (|R.° -|- 32) . 



5. Effects of Wind in Cooling Glass. 



{Jjeuclxars.) 



Velocity of I Vinci 

 per hour. 



minutes 



Time required to lower Temperature 

 front 120 to 100 Fahr. 



