1T I F, which is alſo rectangular, there is known the angle F,
ken by the parallax. Then note in ſome place apart the two
gles I O T and I F T, and of them take the ſines, which are
here ſet down to them, as you ſeen. And becauſe in the triangle
I O T, the ſine T I is 92276. of thoſe parts, whereof the whole
ſine TO is 100000; and moreover in the triangle I F T, the ſine T I
is 582. of thoſe parts, whereof the whole ſine T F is 100000, to
find how many T F is of thoſe parts, whereof T O is 100000;
we will ſay by the Rule of three: If T I be 582. T F is an
100000. but if T I were 92276. how much would T F be.
Let us multiply 92276. by 100000. and the product will be
9227600000. and this muſt be divided by 582. and the quotient
will be 15854982. and ſo many ſhall there be in T F of thoſe
parts, of which there are in T O an 100000. So that if it were
required to know how many lines T O, are in T F, we would
divide 15854982 by 100000. and there will come forth 158. and
very near an half; and ſo many diameters ſhall be the diſtance
of the ſtar F, from the centre T, and to abreviate the
tion, we ſeeing, that the product of the multiplication of 92276.
by 100000, ought to be divided firſt by 582, and then the
tient of that diviſion by 100000. we may without multiplying
92276. by 100000. and with one onely diviſion of the ſine
92276. by the ſine 582. ſoon obtain the ſame ſolution, as may
be ſeen there below; where 92276. divided by 582. giveth us the
ſaid 158 1/2, or thereabouts. Let us bear in mind therefore, that
the onely diviſion of the ſine T I, as the ſine of the angle T O I
by the ſine T I, as the ſine of the angle I F T, giveth us the
ſtance ſought T F, in ſo many diameters T
ken by the parallax. Then note in ſome place apart the two
gles I O T and I F T, and of them take the ſines, which are
here ſet down to them, as you ſeen. And becauſe in the triangle
I O T, the ſine T I is 92276. of thoſe parts, whereof the whole
ſine TO is 100000; and moreover in the triangle I F T, the ſine T I
is 582. of thoſe parts, whereof the whole ſine T F is 100000, to
find how many T F is of thoſe parts, whereof T O is 100000;
we will ſay by the Rule of three: If T I be 582. T F is an
100000. but if T I were 92276. how much would T F be.
Let us multiply 92276. by 100000. and the product will be
9227600000. and this muſt be divided by 582. and the quotient
will be 15854982. and ſo many ſhall there be in T F of thoſe
parts, of which there are in T O an 100000. So that if it were
required to know how many lines T O, are in T F, we would
divide 15854982 by 100000. and there will come forth 158. and
very near an half; and ſo many diameters ſhall be the diſtance
of the ſtar F, from the centre T, and to abreviate the
tion, we ſeeing, that the product of the multiplication of 92276.
by 100000, ought to be divided firſt by 582, and then the
tient of that diviſion by 100000. we may without multiplying
92276. by 100000. and with one onely diviſion of the ſine
92276. by the ſine 582. ſoon obtain the ſame ſolution, as may
be ſeen there below; where 92276. divided by 582. giveth us the
ſaid 158 1/2, or thereabouts. Let us bear in mind therefore, that
the onely diviſion of the ſine T I, as the ſine of the angle T O I
by the ſine T I, as the ſine of the angle I F T, giveth us the
ſtance ſought T F, in ſo many diameters T
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