132 The Horticulturist" s Ride- Book. 



4. Thermometer Scales. 



Fahrenheit. The freezing point is taken as the 320! de- 

 gree of the scale, and 180 degrees are made between that and 

 the boiling point, which therefore becomes 212. 



Centigrade or Celsius. The freezing point of water is 

 taken as the zero, and boiling point as 100. 



Reaumur. The freezing point of water is taken as 

 zero, and 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 than nine is greater than four. 



To reduce Fahrenheit degrees to Centigrade, subtract 32 

 from the given degree of Fahrenheit and multiply the remain- 

 der by 5 and divide it by 9 : (F. 32) J. 



To reduce Centigrade to Fahrenheit, multiply the given de- 

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

 the quotient add 32 : ( J C. _j_ 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) f. 



To reduce Reamur to Fahrenheit, multiply the given degree 

 of Reamur by 9 and divide by 4, then add 32 : (JR. -f- 32.) 



5. Effects of Wind in Cooling; Glass. 

 (Ltuchars.) 



3.26 miles 2:58 minutes. 



5.18 " 2:16 



6 -54 " 1:91 



8.86 " 1:66 



10.90 " 1:50 



I3-36 " 1.25 



iy-97 " 1:08 



20.45 " 1:00 " 



24-54 " -9 1 



27.27 " :8i 



