G. P. Becker—New Feature in the ‘‘Comstock Lode.” 459 
creases in value as we pass down the bar, and having reached 
its maximum at L=112 nearly, it decreases. These tables, then, 
show in the most striking manner the effect of the variation o 
the magnetic permeability of iron upon the distribution of mag- 
netism. 
It is evident that these tables also give the data for obtaining 
the relative values of R’ at different parts of the bar; but the 
results thus obtained are conflicting, and will need further exper- 
iment to obtain accurate results. Where such asmall magnet- 
izing force is used as in Table V. it is almost impossible to 
attain accuracy, and allowance shou e made for this in 
deducing results from it. The greatest liability to error is of 
course where the magnetization is small ; for any small residual 
magnetism which the bar may contain will be more apparent 
here, although. great care was taken to remove all residual 
magnetism before use. Besides this there are many other dis- 
turbances from which the higher magnetizing-powers are free. 
If we accept Green’s formula as correct, these observations give 
us data for determining the magnetizing-function of iron in a 
unique manner, for nearly all other methods depend on absolute 
measurements of some kind. Thus the least value of r? in 
Table IV. for a rod 19 inch diameter is 0142, which gives 
p= 011382, which in Green’s formula (equation 8) gives u=33>8 
for the greatest permeability of this iron; and this is as nearly 
right as we can judge for this kind of iron. It is to be noted 
that Green’s formula has been found for the portion of the bar 
covered by the helix, but as seen from my formule it will ap- 
proximately apply to all portions, though it would be better to 
a new formula for each case. : 
We shall toward the last resume this subject again, and so 
we will leave it for the present. : 
e results which I have now given, and indeed all the 
results of this paper, have been deduced not only from the ob- 
servations which I publish, but from very many others; so 
that my Tables may be considered to represent the average of a 
very extended series of researches, though they are not really so. 
[To be continued. ] 
Art. LVL—WNotes on a New Feature in the “ Comstock Lode ;” 
G. P. Becker. Ph.D., ete. 
a 
THERE is probably no metalliferous vein in the world which 
excites a greater interest than the “Comstock Lode” of Ne- 
vada, whether regarded from a scientific point of view, as the 
argest and richest argentiferous vein yet discovered, or from an 
