66 REPORT—1845. 
part in the combined system of ‘magnetical and meteorological observations 
now in progress. 
‘« Cambridge, February 22nd, 1845. 
“ Str,—As the second triennial period of the combined system of Mag- 
netical and Meteorological Observations will close on the 1st of January 1846, 
it becomes extremely desirable to ascertain, as far as may be practicable, the 
opinions of the various distinguished philosophers who have taken a promi- 
nent part in suggesting or making them, with respect to the expediency of 
continuing them for a longer term. 
“It was with this view that a letter was addressed to you, Sir, by Sir John 
Herschel, the President Elect of the British Association, respectfully request- 
ing your opinion, as far as the results of the observations had come to your 
knowledge, of the extent to which you considered the objects for which they 
were instituted as already accomplished, and also of the advantages which the 
sciences of Magnetism and Meteorology might derive from their longer con- 
tinuance. 
“ Considering, however, the great difficulty of communicating by writing 
the latest results of observations made at such distant stations, and of con- 
centrating into one view the united experience of so many observers, the 
British Association at their last Meeting at York unanimously adopted a 
suggestion made by M. Kupffer of St. Petersburg, to invite the attendance at 
their next Meeting in the University of Cambridge on the 19th of June, of 
the principal cultivators of the sciences of terrestrial magnetism and meteor- 
ology, for the purpose of conferring together upon the course which they 
might judge to be most expedient hereafter to pursue, and of recommending 
to their respective Governments such measures as they might consider best 
calculated to give full effect to this great scientific operation. 
“T have been, consequently, requested by the Council of the British Asso- 
ciation to solicit the honour of your attendance at their next meeting at Cam- 
bridge, which begins on the 19th and closes on the 25th of June; and I beg 
further to inform you that arrangements will be made by Lieut.-Colonel Sa- 
bine and the Staff of Computers placed under his orders by the British Go- 
vernment, to bring under your notice the results of the observations brought 
down to the latest possible period, and to furnish every information which 
an extensive correspondence with the observers and others interested in this 
important inquiry may place at his disposal. 
‘‘ | have reason to believe that the railway between London and Cambridge, 
and between Yarmouth and Cambridge, will be opened before the 19th of 
June; and [ am further authorized to state that the leading Members of the 
University of Cambridge will feel highly favoured by your appearance 
amongst them, and will endeavour to make every arrangement in their power 
which may contribute to your comfort and convenience during your visit. 
“ If it should be your intention to attend the proposed conference, I should 
feel obliged to you if you would communicate your intention to Lieut.-Colonel 
Sabine at Woolwich, who will gladly furnish you with any further informa- 
tion which you may require. 
**T have the honour to be, Sir, 
*‘ With the greatest consideration and regard, 
“Your most obedient servant, 
(Signed) “GEORGE Pracock, 
“« President of the British Association.” 
