376 Proceedings of the British Association. 
to be confounded and masked by the growing influence of other 
shocks nearer the principal point of observation. The report re- 
commended smaller bars than those now in use, as more easily 
affected by sudden shocks. It was now considered advisable to 
collect from all sources to which we had access, accounts of the, 
remarkable disturbances beginning with 1840 and 1841, arrang- 
ing them in chronological order, and publishing them in volumes 
by themselves, and the first volume would be published in the 
course of this summer. The great disturbance of Sept. 25, 1841; 
which was observed at Greenwich, and was immediately made 
the subject of a circular from the Astronomer Royal to his broth- 
er observers, was also observed at Toronto, St. Helena, the Cape 
of Good Hope, and Trevandrum in Travancore. All these arri- 
ved in time to be inserted in the volume for 1841 ; and surely it 
must be regarded as a remarkable fact, that this casual phenome- 
non was seized upon by our observers in Europe, Asia, Africa and 
America, reported thence to England, reduced and printed, in 
three months and one week after its occurrence ; “tantum series 
juncturaque pollet.”. The returns from the different stations 
showed that these disturbances were general; that, though the 
movements individually might not be, and in -fact were not, al- 
ways simultaneous, the observations on the same day never failed 
to exhibit unusual discordances at all the stations, and were gen- 
erally characterized by the diminution more or less of the hori- 
zontal intensity, prevailing more or less for several hours every 
where, and the movement of the north end of the needle towards 
the west. Besides the colonial observatories, these phenomena 
were watched with great attention at the observatories of Prague, 
Munich and Greenwich. ‘The report next noticed the new mag- 
netic instruments and modes of observation. We can only enu- 
merate the former, viz. the transportable magnetometer, Dr. 
Lloyd’s induction inclinometer, Weber’s inductive inclinometer, 
and another method proposed by Dr. Lamont. The report next 
enumerated the publication of various magnetic observations. 
The only expense incurred by the Association during the year 
was about £11 for observatory registers, and the committee 
* (To be continued.) 
Pa 
