16 
EXPLANATIONS. 
Local Mean Time is used for the regular observations. 
The Barometer readings, taken at 9 asm. and 9 p,m., are corrected and 
reduced to sea-level and 32°0° Far. 
The Approximate Mean Temperature is the mean of the maximum and 
minimum read at 9-0 a.m., and found by multiplying their difference by the 
Meteorological Office co-efficient, and adding the product to the minimum. 
Temperature in Sun read at 9 a.m., and placed to previous day. 
Ground Temperatures read twice daily at 9-0 a.m. and 9-op.m. The 
lowest reading for the 24 hours, ending at 9-0 a.m., is entered to the previous 
day. 
Underground Temperatures taken daily at 900 a.m. The air tempera- 
ture is given for purposes of comparison. 
The Relative Humidity is calculated by dividing the mean elastic force 
of Aqueous Vapour, at the temperature of the Dew point (as determined by 
Glaisher’s Factors), by that corresponding to the temperature of the air 
(z.¢., the Dry-bulb reading). 
The Rain is measured at 9-0 a.m., and the amount entered to the pre- 
vious day. A fall of 0-006 inch and above constitutes a day of rain. When 
any snow falls, the day is counted as a day of snow. 
When the mean of the 9-0 a.m. and 9-0 p.m. observations of the amount 
of cloud is less than 2:0, it is called a day of clear sky; if the mean is above 
8-o an overcast day. 
The Wind direction is taken by means of a Compass Nephoscope, from 
the drift of the lower clouds. 
When the Force of the Wind is 7 and above (on Beaufort’s Scale o—12), 
it is accounted a Gale. 
Sunshine Record.—The photographic traces are fixed before being 
measured. 
Fog, &’c.—The fog, haze, &c., are made from the visibility of objects 
and lights at definite distances from Rutland Cottage. 
