( <45 ) 
very evident, that they did not all change their De- 
cimation equally. I have before taken notice, that 
it appeared from Mr. Molyneaux's Obiervations, 
that y ‘Draconis altered its Declination about twice 
as much as the fore-mentioned fmall Star almoft op- 
pontc to it 5 but examining the matter more particu- 
larly, I found that the greateft Alteration of Declina- 
tion in thefe Stars, was as the Sine of the Latitude 
o each relpediivcly . This made me lufpedt that 
there might be the like Proportion between the 
Maxima of other Stars ; but finding, that the Ob- 
iervations of fome of them would not perfectly cor- 
refpond with fuch an Hypothefis, and not knowing 
whether the fmall Difference I met with, might not 
be owing to the Uncertainty and Error of the Ob- 
iervations, I deferred the farther Examination into 
the Truth of this Hypothefis, till I fhould be fur- ' 
nifhed with a Series of Obfervations made in all 
Parts of the Year ; which might enable me 
not only to determine what Errors the Obferva- 
tions are liable to, or how far they may fafely be 
depended upon; but alfo to judge, whether there had 
been any fenfible Change in the Parts of the Jnftru- 
ment irielf. 
Upon thefe Confiderations, I laid afide all Thoughts 
at that Time about the Caufe of the fore-mentioned 
Phenomena, hoping that I Ihould the eafier difeover 
it, when I was better provided with proper Means to 
determine more precifely what they were. 
When the Year was compleated, I began to exa- 
mine and compare my Obfervations, and having pret- 
ty well fatisfied my felf as to the general Laws of the 
'Phenomena, I then endeavoured to find out the 
Caufe 
I 
