2° His elliptical iter planetarum. for me thinks it shiews a Way to the folving of the unknown walks of comets. For ai his Ellipfis in the Earths motion is more a circle _[here endeth Dr Zacb’s fragment, and here beginneth the continuation from tie original in the Britith Museum]_ and in Mars is more longe and in some of the other planets may be longer againe so in thos commets that are appeard fixed the ellipsis may be neere a right line. 3. His phansie of ecliptica media or his via regia of the sun, vnto wch the walke of al the other planets is obliqj more or lesse; even the ecliptica uera under wch the earth walkes his yeares journie; by wch he solues handsomelie the mutation of the starres latitudes. Indeed I am much delighted with his booke, but he is so tough in rnanie places as I cannot bite him. I pray write me some instructions in your next, how I may deale with him to ouermaster him for I am readie to take paines, te modo jura dantem indigeo, dictatorem exposco. But in his booke I am much out of loue with thes particulars. I. First his manie and intolerable atechnies, whence deriue thos manie and vncertaine assayes of calculation. 2. His finding fault with Vieta for mending the like things in Ptol: Cop..... but se the justice Vieta speakes sleightlie of Copernicus a greater then Atlas. Kepler speakes as slightlie of Vieta, a greater then Appollonius whom Kepler everie wher admires. For whosoever can doe the things that Kepler cannot doe, shalbe to him great Appollonius. But enough of Kepler let me once againe intreate your counsel how to read him with best profit, for I am wholie possessed with Astronomical speculations and desires. For your declaration of Vieta’s appendicle it is so full and plaine, as you haue aboundantlie satisfyed my desire, for wch I yield you the thankes I ought, onlie in a word tell me whether by it he can solue Copernicus, 5 cap: of his 5. booke. The last of Vieta’s probleames you leaue to speake of because (you say) I had a better of you, wch was more vniuersal and more easilie demonstrated, and findeth the point, E. as wel out of the plaine of the triangle giuen, as in the plaine. I pray here helpe my memorie or vnderstand-inge, for although I haue bethought my selfe vsq ad insaniam, I cannot remember or conceaue what proposition you meane. If I haue had such a one of you, tel me what one it is and by what tokens I may know it ; If I haue not had, then let me now haue it, for you know how much I loue your things and of all wayes of teaching for richnesse and fullnesse for stuffe and forme, yours vnto me are incomparablie most satisfactorie. If your leasure giue you leaue imparte also unto me somewhat els of your riches in this argument.