
ON MAGNETICAL AND METEOROLOGICAL OBSERVATIONS. 59 
ferences from Munich, an arrangement of which it is not very easy to per- 
ceive the advantage. ‘The volume in question contains also an investigation 
by Dr. Lamont of the law of distribution of magnetism in magnetised bars, 
in which various methods of determining by observation the coefficients of 
an empirical series representing the intensity of free magnetism in ascending 
powers of the distance of a point from the centre of the magnet are proposed. 
By a communication from M. Boguslawski it appears that in spite of great 
difficulties arising from want of regular assistants the observations at Prague 
have been regularly continued, not only on all the term days, but, since Ja- 
nuary Ist of the current year, also daily at four hours in each day with all the 
three instruments. Perceptible magnetic disturbances have been noticed by 
him on January 1, October 6, February 24, March 29 (very great), April 5, 
May 15, and July 24. 
3. Magnetic Surveys. 
At the request of the East India Company the magnetic observatories of 
Simla and Singapore have been supplied with a portable magnetic apparatus, 
which we hope will be speedily and extensively employed in magnetic surveys 
having the respective observatories as central points. 
M. Kreil is about to add to his most useful observatory labours a magnetic 
survey of Bohemia, for which he has obtained portable apparatus on the con- 
struction proposed by Dr. Lamont. 
4, North American Survey. 
Letters have been received from Lieut. Lefroy dated from Lachine on the 
28th of April, and from Sault S** Marie, May 20th of the current year, giving 
an interesting account of his progress so far on his arduous expedition, and 
detailing his plan of operations, for this and the next year with a sample of 
each day's performance. Lieut. Lefroy reached Montreal on the 22nd of 
April, where also his instruments arrived on the 25th (not altogether without 
injury to the force of his magnets from the extreme badness of the roads), 
Here, on consultation with Sir G. Simpson, he found it advisable to recast 
the plan of his route and to resolve on proceeding first to York Fort, and re- 
turning thence to Norway House, ascend. the Sascatchewan to Edmonton, 
which he expects to reach on the 20th of September, whence, crossing the 
Uniga to descend it on the ice to the Slave Lake and return to Athabasca for 
the remainder of the winter, working his way back to Canada in the next 
season and taking Moose Fort on the way back. By the adoption of this 
route a more complete circuit of the focus of maximum intensity will be 
accomplished than by that originally contemplated. Every necessary order 
and instruction and every facility he states to have been most readily ac- 
corded, and in particular a circular to have been issued to all the officers of 
the Hudson’s Bay Company, amounting to a carte blanche, commanding all 
the resources of the Company. The line of no variation Lieut. Lefroy states 
to have been crossed between La Cloche and Sault S$‘ Marie, up to which 
point little change of dip had been experienced, his course leading him nearly 
along the isoclinal line of 77°. 
5. Naval Observatories. 
The second series of Sir Edward Belcher’s magnetic determinations at 
thirty-two stations, principally at ports in the Pacific Ocean and in the Indian 
and Chinese Seas, have been reduced by Lieut.-Colonel Sabine and printed 
in the 2nd Part of the Phil. Trans, for the present year. The two series of 
Sir Edward Belcher’s observations, which are now printed in the Phil. Trans., 
contain determinations of the three magnetic elements at sixty-one stations 
