AT MUNICH, 1840, 1841, 1842. 615 
clination amounted to 25!, one of the greatest which we have yet 
observed), until the return of the lower culmination of the sun. 
The numerical values for the inclination and the total inten- 
sity are, however, to be regarded as only a provisional approxi- 
mation ; they rest on the assumption that a scale-division corre- 
sponds to 13'*1 of inclination, as would be the case if the inten- 
sity of the magnetism of the iron and its variations were in the 
same proportion as the intensity of the vertical portion of the 
earth’s magnetism and its variations. But as we are not justi- 
fied, @ priori, in making this assumption,—and as, moreover, the 
hitherto generally received supposition, that with the increase or 
decrease of the magnetic moment ofan iron bar each element in- 
creases or decreases in the same ratio, stands yet in great need of 
confirmation,—we must determine the value of the scale-divisions 
by means of deflection in a manner similar to that which can be 
made use of in the horizontalintensity. I have not performed this 
operation, but I have, by means of a magnet, induced in the iron 
about as much magnetism as is equivalent to five times the 
greatest change in the earth’s magnetism which has yet fallen 
under my notice, and I have found that, after the removal of the 
inducting magnet, the needle returned very soon to precisely its 
previous condition, so that in small changes the resistance of the 
iron may be regarded as vanishing, just as imperfectly elastic 
bodies, in small alterations of the compressing forces, may be 
regarded as perfectly elastic. 
There appears, therefore, to remain no doubt that the induc- 
tion of soft iron may be applied with equal ease and certainty to 
the measurement of the variations of the inclination. Mr. Lloyd 
has not succeeded in obtaining by its means a determination of 
the absolute inclination ; the endeavours made in this view in the 
Munich Observatory, with I hope some success, not being yet 
completed, the. account of them must be reserved for a future 
occasion. 
2. Remarks on Dr. Lloyd’s method of Determining the Absolute 
Horizontal Intensity. 
Dr. Lloyd has sent the editor his memoir entitled “ On the 
Determination of the Earth’s Magnetic Force in Absolute Mea- 
sure.” Dr. Lloyd’s method may be characterised as follows :— 
1. When the distance of the deflecting from the deflected 
magnet is four times, or more than four times, greater than the 
