50 
HINTS TO TRAVELLERS. 
In the Table is given the relative humidity for every 2° of temperature 
from 20° to 80°, and for every two-tenths of a degree of difference between 
the dry and wet-bulb readings from 0° * 2 to 18° * 0. 
To use the Table: Look in the column on the left or right for the 
nearest degree to the dry-bulb reading ; then carry the eye horizontally 
along until the column is reached corresponding to the difference between 
the readings of the dry and wet-bulb thermometers, when the relative 
humidity will be found. Intermediate readings can be interpolated in 
the usual way. 
Example: Dry-bulb 58° *5, wet-bulb 52° *7, the difference is 5° *8. 
Having found 58° in the column on the left or right, run the eye along 
this line until the column under 5° *8 is reached, when the relative 
humidity will be found, viz., 67. 
