Mr. Hobbes hath these words: “_Longitudinem percursam motu uniformi, cum impetu ubique ipsi B D æquali_.” Dr. Wallis saith _cum_ were better out, unless you would have _impetus_ to be only a companion, not a _cause_. Mr. Hobbes answered it was the _ablative case of the manner_. The truth is the ablative case of the _manner_ and _cause_ both, may be used with the conjunction _cum_, as may be justified. Cicero in Lib. II. _De Nat. Deorum_: “_Moliri aliquid cum labore operoso ac molesto_;” and in his oration for Cæcina: “_De se autem hoc prædicat, Antiocho Ebulii servo imperasse ut in Cæcinam advenientem cum ferro invaderet_.” Let us see then what Dr. Wallis objects against Tully, where a casualty is imported, though we may use _with_ in English, yet not _cum_ in Latin; to kill with a sword, importing this to have an instrumental or causal influence, and not only that it hangs by the man’s side whilst some other weapon is made use of, is not in Latin _occidere cum gladio_, but _gladio occidere_. This shows that the Doctor hath not forgot his grammar, for the subsequent examples as well as this rule are borrowed thence. But yet he might have known that great personages have never confined themselves to this pedantry, but have chosen to walk in a greater latitude. Most of the elegancies and idioms of every language are exceptions to his grammar. But since Mr. Hobbes saith it is the ablative case of the manner, there is no doubt it may be expressed with _cum_. The Doctor in the meantime knew no more than what Lilly had taught him; Alvarez would have taught him more; and Vossius in his book, _De Constructione_, _cap._ XLVII. expressly teacheth, “_Ablativos causæ, instrumenti, vel modi, non a verbo regi sed a præpositione omissa, a vel ab, de, e vel ex, præ, aut cum, ac præpositiones eas quandoque exprimi nisi quod cum ablativis instrumenti haud temere invenias_;” and afterwards he saith, “_non timere imitandum_.” If this be so, then did Mr. Hobbes speak grammatically, and with Tully, but not _usually_. And might not one retort upon the Doctor, that Vossius is as great a critic as he?