54 Lovering and Bond on Magnetic Observations at Cambridge. 
28-9. Unfortunately the Magnetometer was not watched on the 
night of May 28-9. By referring to Plate IV. it will be seen that the 
Declination instrument was subject to more than ordinary influences 
on the 22d of October between 0" M. and 6" A. M. Gott. M. T. 
The observers on the remarkable days of May and August de- 
scribe the motions of the Magnetometer as peculiar in the highest 
degree. It was often checked in the midst of its vibration and 
suddenly forced back in the opposite direction; and this took place 
with such frequency at certain seasons as to give to the motion the 
appearance of jerks or sharp twitches. No correspondence was 
noticed between the time of maximum magnetic disturbance and 
the formation of the auroral crown. But it was sometimes supposed 
from successful comparisons in the phases of the different phenome- 
na that the instrument gave intimation by some strange motion of 
the most signal changes in the Aurora. The display of May and 
August was as fine as any that has been witnessed for several 
years and we should not omit to state that on these occasions the 
Declination Magnetometer at Cambridge made the boldest sweep 
of the scale. As both these_days happened to be Term-days the 
opportunity was improved at other magnetic Observatories of watch- 
ing the coincidence between the auroral appearances and the per- 
turbations, and the report is generally uniform from all. Plate IL. 
which represents the May-term diurnal curve of declination offers 
a specimen of the extraordinary disturbances to which we refer 
and the time of them may be compared with the phases of the 
Aurora which are contained in the record for that day. The ex- 
cursion at g was so great that it was found necessary to curtail it on 
the Plate; but the extent will be readily seen from remarking that 
it reached to 71.4 on the scale, 47.2 of which were traversed in 
11 minutes of time. An Aurora was seen on the same night at 
