32 Lovering and Bond on Magnetic Observations at Cambridge. 
solar influence it is to be observed that no more exact uniformity 
is to be expected in them than in the legitimate and acknowledged 
influences of the sun ; that is to say, the earth’s temperature. 
Yet farther supplementary to the plan recommended by the 
Royal Society, a series of observations has been undertaken at 
Cambridge with the express object of throwing additional light on 
this interesting inquiry. As early as May, 1840, the observations 
took a wider range so as to furnish a diurnal curve not only for the 
Term-day but also for several other days in the same part of the 
month. The following Table shows the days over which the ob- 
servations were extended, including the prescribed Term-days. 
Term-day. Extra Days. 
1840. May May 29 | May 21, 22, 23. 
June June 24] June 21, 22, 23, 25, 26, 27, 28, 29, 30. July 1. 
July July 24. 
August August 28] August 29, 30,31. September 1. 
September | September 23 | September 21, 22, 24, 25. 
October October 21 | October 20, 22, 23,24. 
November | November 27 | November 23, 24. 
December | December 23 | December 21, 29. 
1841. January January 20) January 22, 25. 
February February 26 | February 24. March 1. 
On all the preceding days observations were made during the 24 
hours so as to furnish materials for drawing as many diurnal 
curves. The mtervals between the observations were not always 
five minutes as on the Term-days. Thus in May the interval was 
15 minutes and in June and July 20 minutes. Again, in August 
the interval was only four minutes. In August, reasons appear- 
ed for recording the Thermometer at intervals of 20 minutes on 
all the days when the Magnetometer was observed. This was 
sufficient to give all the regular daily thermometric changes. 
In October, the Barometer was observed every 20 minutes during 
the five days. The observations on the Barometer have not been 
repeated as they did not promise to facilitate the inquiry upon 
