8 INTRODUCTION. 



pattern (No. 954). It bung inside Mr. Livingston's house, with its cistern 33 feet above 

 sea level. A Richard Barograph in the same room served as a check and a means of 

 interpolating any omitted readings. The Thermometers and Raingauge were placed 

 on a grass plot at the back of the house, the thermometers being in a Stevenson 

 Screen with the bulbs of the Dry and Wet four feet above ground, and the raingauge 

 circular 5 inches in diameter and with rim a foot above ground. A Richard 

 Thermograph in an adjacent screen was used as a check on the Eye readings. 



Each month's record forms one table, the first group of columns being the barometric 

 readings reduced to 32° and sea level, with the first figure of each entry omitted as 

 explained above. The second group are the readings of the Dry and Wet Bulbs 

 corrected for instrumental error ; then the Maximum and Minimum registering ther- 

 mometers, with the highest and lowest in each month put in bold-faced type. Then the 

 Direction and Force of the Wind on the same scale as used at the Ben Nevis Observatory ; 

 the Amount of Cloud ; and the Rainfall for each twenty-four hours ending 9 a.m. of the 

 next clay : thus the amount entered on 1st January is what fell between 9 a.m. on the 1st 

 and 9 a.m. on the 2nd. The heaviest daily fall in each month is put in bold-faced type. 

 At the top of each column is the hour at which the readings were taken, and at the 

 foot the averages or totals for the month. 



Monthly and Annual Mean Values. — In these tables are given the monthly 

 mean values of the Barometer and Dry Bulb Temperature for each hour at Ben Nevis 

 and Fort-William Observatories, the monthly hourly sums of the Rainfall and Sunshine 

 at these Observatories, and the hourly mean values of Wind-force and total cases of each 

 wind direction (reduced to 8 points) for each month at the Ben Nevis Observatory. 

 The annual values are the sum or mean of the twelve monthly values. 



Log-Book. — In this are noted any changes of instruments or modes of observing at 

 Ben Nevis Observatory, all observations of Auroras, Halos, Thunderstorms and other 

 similar phenomena that do not appear in the tabular records, and various matters of 

 general interest connected with the Observatory. 



Depth of Snow. — At the end of the annual returns a table is given (page 419) 

 showing the depth of snow on the summit of Bevis Nevis on the 1st and 15th of 

 each month from the opening of the Observatory to June 1893, with the mean 

 values for these ten years. 



