18 Magnetical: Dip in the Omited States. 
ee. 
lines marked by the Architect of the Universe. My observations 
were intended to be tried by no other standard than the last. 
I come next to Prof. Loomis’s remarks against the truth. of my 
observations. 
On page 88, he doubts whether I have abn to reading 
both ends of the dipping needle, so as to avoid the error “ arising 
from the eccentricity of the axis of the needle in relation to the 
vertical circle, on which the readings are made.” He says, “ this 
error in my instrument, commonly amounts to one or two min- 
utes, and sometimes to even five or more. It is corrected by 
reading at both extremities of the needle.” From my saying 
that I determined the dip by 8 distinct readings, he thinks I “im- 
plied that I did not attend to the above precaution.” ‘This is all 
naivete enough. I regret that Prof. Loomis should have formed 
so low an estimate of my skill, as to suppose I would use a grad- 
uated circle, where it was possible to obtain the mean of two op- 
posite readings without doing so,—a thing so obvious that I 
deemed it unnecessary to say any thing about it. My needle 
No. 1, when properly adjusted, shows no eccentricity, but reads 
alike at both extremities. No. 2; has almost uniformly a differ- 
ence of 5 minutes at the opposite ends. Both ends of both nee- 
dies were always o red. If such be called a separate reading, 
then 16 should be substituted for 8 in the quotation above, and 
my readings should all be counted double: he number which I 
have assigned to them. 1 
The next paragraph is upon “ the uncanny of the readings” 
themselves.” [should not have known how to reply to that 
_ expression, but he subsequently becomes more specific. ‘The 
or arising from friction on the axis,” he says, ‘is exhibited in 
Prof. Locke’s observations in a striking light.’ 1 find by the 
subsequent remarks that he refers to an observation at Davenport, 
as published in Vol. xxxrx, of this Journal, in which there was 
an erratum, which had been the subject of correspondence be- 
tween the Junior editor and myself. This erratum was the re- 
sult of transcription. "The amount of the several items, was cor- 
rectly written, but one of the items which in the field-book reads 
72° 55’ had been transcribed 72° 05’. The Junior editor dis- 
covered the discrepancy between the items and their amount, and 
very naturally corrected the latter instead of the former, at the 
same time kindly addressing a note to me on the subject, which, 
as I was absent, I did not receive, It went to press in the erro- 
vat 
