_Extract of a Letter written from _Rome_, concerning the late _Comet_, and a _New_ one. Extract of another Letter from _Paris_, containing some Reflections on the precedent _Roman_ Letter. An Observation concerning some particulars, further considerable in the _Monster_, that was Mention'd in the first Papers of these _Philosophical Transactions_. Extract of a Letter written from _Venice_, concerning the Mines of _Mercury_ in Friuly. Some Observations, made in the ordering of _Silk-worms_. An Account of Mr. _Hooks Micrographia_, or the Physiological descriptions of _Minute Bodies_, made by _Magnifying Glasses_._ * * * * * _Extract of a Letter, lately written from _Rome_, touching the late Comet, and a New one._ I Cannot enough wonder at the strange agreement of the thoughts of that acute French Gentleman, Monsieur _Auzout_, in the _Hypothesis_ of the Comets motion, with mine; and particularly, at that of the _Tables_. I have with the same method, whereby I find the motion of this Comet, easily found the Principle of that Author's _Ephemerides_, which he then thought not fit to declare; and 'tis this, that this Comet moves about the _Great Dog_, in so great a Circle, that that portion, which is {18} described, is exceeding small in respect of the whole circumference thereof, and hardly distinguishable by us from a streight line. Concerning the New Comet you mention, I saw it on the 11. of _February_, about the 24. deg. of _Aries_, with a Northern latitude of 24. deg. 40. min. The cloudy weather hath not yet permitted me to see it in _Andromeda_, as others affirm to have done. * * * * * _Extract of a Letter, written from _Paris_, containing some Reflections on part of the precedent _Roman_ Letter._