In 1705, with the mathematical assistance of Issac Newton, Edmond Halley published Synopsis of the Astronomy of Comets which made the prediction that the comet observed in 1682 had previously been observed in 1531 and 1607 was the same object returning about every 76 years or so. He included a rough estimation of the gravitational effects of Jupiter and Saturn, and predicted it would return in 1758.
Is there anything written specifically about mathematics used in a "rough estimation of the gravitational effects of Jupiter and Saturn"? Was the size of the effect on the comet's orbit mentioned, or anything about how the calculation was made?
Just fyi the linked answer also cites Wikipedia's Halley's Comet and the passage cites page 86 of P. Lancaster-Brown (1985). Halley & His Comet. Blandford Press. ISBN 0-7137-1447-6.