26 REPORT—1840. 
approach, is the least possible when they contain equal quantities of 
electricity. It follows also, that the more unequal a and y are, the 
t f 
greater must the sum of A’gy and A’q= be; that is, the more the 
x 
electrical quantities of the two corpuscles differ, the greater is their 
tendency to mutual approach. The phenomena of electrical attraction, 
repulsion, and quiescence, may be explained on this theory, ina manner 
perfectly satisfactory, and exceedingly easy. 
The author then exemplified this in the following cases : 
1. QUIESCENCE. 
Case 1—JLet A BC D be four small balls, equal to each other, 
homogeneous, equidistant in the same straight line, and all in the neutral 
electrical state. 
Case 2.—Let A be electrified plus, while C B D remain in the 
neutral state. 
Case 3.—Let A be electrified minus, while B remains in the neutral 
state. 
2. ATTRACTION. 
Let A be positively, and B negatively, electrified. 
3. REFULSION. 
Case 1.—Zet A and B be alike electrified plus. 
Case 2.—Let A and B be alike electrified minus. 
An Account of the Magnetic Observatory of Munich. 
By Dr, Lamont. 
The author stated that the building had been undertaken in April 
this year, and that the regular series of observations, comprehending 
both the daily observations from two to three hours, and the term-day 
observations, was commenced on the Ist of August. The Magnetic 
Observatory of Munich differs in two respects from other establishments 
of the same kind. In the first place, it is not a magnetical house, but 
a subterraneous building, which is situated to the S.W. of the Royal 
Observatory, and at a distance of about 120 feet, and connected with 
it by a subterraneous passage. The depth of the magnetic observatory 
below the surface of the earth is 13 feet, thus affording the advantage 
of a temperature nearly equal at all times of the year, and rendering 
the corrections applied to magnetic observations in order to reduce 
them to a fixed temperature—corrections which are in general subject 
to considerable uncertainty—if not unnecessary, at least sufficiently 
small to be determined with the utmost degree of accuracy. In the 
second place, the instruments are of greater dimensions than those ~ 
usually employed in magnetic observatories, and may be considered as 
sufficient in all respects for the most delicate investigations. The mag- 
netic bars weigh 25lbs. each ; the theodolite has a circle of 23 feet dia- 
