42, Lovering and Bond on Magnetic Observations at Cambridge. 
On September 22-3, the Magnetometer was more quiet; oc- 
casional oscillations of considerable extent occur but the maximum 
point is very regularly formed at 11" 36’ A. M. and the minimum 
though less definite is placed at 6" 06’ A. M. On September 24th 
westerly disturbances take place between 4° 36' and 74 36’ A. M., 
the time when the minimum generally shows itself; the effect is to 
bring the mean curve at this period too far to the west or to make 
the apparent mean time of maximum earlier than it is in fact or 
would appear if the observations were free from irregular varia- 
tions. These derangements do not cease till nearly the close of the 
third magnetic day so as to throw uncertainty on the time of maxi- 
mum of this day also. 
September 24-5, (Magnetic day.) Disturbances break out again 
in strange forms. This day was affected by wholly unprecedented 
motions distinguished not so much for their extent as for their num- 
ber and the rapidity with which they succeeded one another. A 
faint idea of them is conveyed by looking at those which occurred 
between 7" 20’ A. M. and 7" 40’ A. M. Gott. M. T. of October 22d, 
represented on Plate IV. The direction of the motion changed 60 
times or more from east to west and back between 1° and 2" P. M. 
Gott. M. T. The whole sweep of the needle for this day is only 26’, 
an area much less than is often traversed in the diurnal motion; but 
the number and frequency of the oscillations is unparalleled. The 
greatest declination occurs at 3" 06’ A. M. Cambridge M. T. and 
the least at 3" 36’ P. M.; but another minimum more nearly resem- 
bling the regular daily minimum appears at 5" 36’, A. M. 
September 25-6, (Magnetic day.) The magnetic storm has 
subsided. The curve for this day is as quiet as that of the 4th day 
on Plate IV. The eye readily perceives that now we have only 
regular diurnal changes and that the times of greatest and least 
