Ixii. InTRODUCTION TO THE MAKERSTOUN OpsERVATIONS, 1845 AND 1846. 
The fourth column contains the temperature of the bifilar magnet in degrees of 
Fahrenheit. 
The fifth column gives the readings of the balance magnetometer in micrometer 
divisions, corrected for temperature to 26° Fahr. (see No. 79); increasing numbers 
indicate increasing force. The balance is observed 3™ after the declination. 
The sixth column contains the temperature of the balance magnet in degrees of 
Fahrenheit. ; 
The seventh column contains the observer's initial (see No. 5). 
At the foot of each page the time is given during which the declination mag- 
net has remained untouched, or the amount of torsion found in the suspension thread 
when that has been determined (see No. 12). The value, k, of one scale division of 
the bifilar magnetometer, the whole horizontal component being unity (see No. 40), 
and the value, &, of one micrometer division of the balance magnetometer, the 
whole vertical component being unity (see No. 60), are also given. 
108. Term-Day Observations of Magnetometers, 1845, pages 72-87. 
The first column contains the minute of Gottingen mean time of the declina- 
tion observations, the hour being given in the middle of each triplet of columns. 
The first column of each triplet contains the absolute westerly declination ; the 
second and third columns contain the bifilar and balance magnetometer readings, 
reduced to the temperature of 26° Fahr., as in the hourly observations. The 
temperatures of the magnets at the commencement of each hour will be found 
with the hourly observations, and the observer’s initial for each hour are in the same 
place. The corrections for temperature are applied to the observations in the fol- 
lowing manner :—The correction to the first observation of each hour being applied 
for the known temperature of each magnet, the temperature is supposed to change 
uniformly throughout the hour, and the corrections for the intermediate observations 
are interpolated between the initial corrections. 
109. Letra Observations of Magnetometers, 1845 and 1846, pages 90-117 and 
326-341. 
These observations are made generally during magnetic disturbances. The 
same remarks apply with reference to temperature corrections, &c., as for the term- 
day observations, excepting that the Gottingen day and hour are given in the first 
column, and the minute is given for the observations of each instrument. Notes 
upon the Aurore boreales observed are given, with the times of the phenomena in 
Gottingen mean time, pages 118-127 and 342-343. 
110. Observations of Magnetic Dip, and for the Absolute Horizontal Intensity. 
See Nos. 19, &c., 82, and Addendum to Introduction. 
111. Hourly and Daily Meteorological Observations, 1845 and 1846, pages 136— 
272 and 354-409, 
The first column contains the day and hour, Gottingen mean time, of the obser- 
vations, all of which are made within a few minutes of the hour, and generally in 
