226 Observations upon Auroral and Optical Phenomena. 
sumed also the appearance of an arch, running nearly parallel with 
the other. It remained stationary, becoming now and then less dis- 
tinct and again resuming its original brightness. A few faint beams 
of light radiated from the northwest towards the zenith ; the sky was 
perfectly free from clouds, but was overspread with a thin veil of 
light rendering the smaller stars obscure. The weather was cool, 
with a wind due north. 
In the comparison of the foregoing observations with each other, 
they manifest a consistency extending through every period of the 
bow’s progress and duration. Thus, in the first stages of the bow, 
and very soon after its formation, Mr. Ellsworth, at Hartford, saw it 
lying north of the Crown ‘and of Castor,—certainly at nearly the 
same moment when Mr. Allen, sixteen miles south of him in latitude, 
saw the same entirely north of Benetnasch, in the tail of the Great 
Bear. There would seem by this to have been a parallax of about 
half the breadth of the bow, or a little more—say 7°, to a base of 
sixteen miles. Again, in the middle stages of the bow, Prof. Olm- 
sted, fifteen minutes before its disappearance, saw it passing through 
the Northern Crown, in a position certainly not varying widely from 
that assigned to it in the same constellation, by Mr. Ellsworth, twenty 
five minutes before the disappearance. The parallax, therefore, due 
to a base of thirty two miles would seem by this to be equal to the 
motion of the bow in ten minutes—say 12°. Finally, in the last 
stages of the bow, Prof. Olmsted saw it vanish when its south mar- 
gin had just reached Arcturus, while Mr. Allen, sixteen miles north, 
saw its middle upon Arcturus “ just before” the disappearance,— 
and while Mr. Ellsworth, still sixteen miles farther north, saw the 
same star in the same position relatively to the bow, “ten minutes” — 
before the disappearance. The parallax between the stations at 
New Haven and Hartford, would, by the last comparisons, appear 
to be something greater than the-motion of the bow during the last 
ten minutes of its appearance, during a part of which ten minutes, 
according to Prof. Olmsted, it was stationary. The motion was 
about the same according to each observer—rather exceeding, in the 
average of all three, one degree toa minute. The breadth of the 
bow in its middle stages, appears by Prof. Olmsted’s observations to 
have been about 12°. It is impossible, from the foregoing observa- 
tions, to fix upon a definite parallax, although we may approximate 
to it with entire certainty. The observations are perfect in relation 
to the general Seen al the présent paper—since the largest paral 
