of the variable Star in Sobieski’s Shield. 151 
offered to the public, either with or without corroborating ob- 
servations ; nor do I presume to think, that the explanations 
are the only ones or best that can be imagined, the more so, 
as they solely refer (for greater simplicity) to the star’s 
equator, while possibly, were the spots placed in a northern or 
southern latitude, or permanent ones near the poles, or were a 
proper inclination, given to the polar axis, they might be more 
satisfactory : however, the materials themselves, the observa- 
tions and deductions will I flatter myself ever be acceptable, and 
contribute to facilitate future conjectures, which from an allow- 
able analogy may extend to similar parts of the starry system, 
with regard to the probability of establishing whether any of 
the most irregular or particular changes may not return at Jixt 
periods, or after a certain number of rotations. I think we can 
entertain but slight hopes of it, owing to the great fluctuation of 
the luminous matter, as shewn by the perpetual varying of the 
apparent revolutions, magnitudes See. See Tab. IX. X. and VII. 
Still it is natural to suppose, that some parts of the atmosphere 
of this star may have a less tendency than others to become 
luminous, so as to promote at different times, similar appear- 
ances ; and indeed this is strongly indicated by the intervals of 
the minima being far more regular than those of the full brightness , 
which, with other reasons induce us to suspect that even one 
of its hemispheres is less favourably constituted or qualified, 
than the other for the generating of these particles, although 
they do occasionally encroach on both sides, as appears by the 
observations between June and August, See Phil. Trans, for 
1797, or ^e eight sketches of 1756, and likewise in 1797, see 
Tab. VII. when during three months it was only reduced to the 
5 or 6 Mag. by which the degree of brightness that surrounded 
