future, they must be expressed by a future tense. Now arrive has a future meaning; therefore a future tense. But which of the two? First or second? That depends on the nature of the action; if the verb of the dependent clause denotes an action antecedent to that of the principal clause, it must be put in the tense which denotes antecedence. Now, let us see: the arriving at Philadelphia necessarily antecedes the giving of the letter; consequently I have to use the second future, the futurum exactum: ubi primum – venio, Perfect veni – well: perveneris. At Philadelphia; at is in; however, names of cities are construed without a preposition, they are used in the locativus, which in singular nouns of the 1st and 2nd declensions is like the Genitive case, therefore Philadelphiae. But is there not a rule about advenire, pervenire, congregari, etc.? They mean going towards, into, therefore I must use the construction answering the question: whither, therefore Philadelphiam. Very well. Now: give him the letter; give: trade, da; him: eum, but stop – eum is direct object, while in the given sentence him is indirect, so it must be ei, trade ei epistolam. – To prevent, is the infinitive, here it expresses a purpose. Clauses denoting purpose are not expressed by the infinitive in Latin prose, but by ut, causa with the gen. of the Gerund, or ad with the accusative, etc.; take ut: but attend to the sequence of tenses! – impedias eum; from going: a proficiscendo? No! but: quominus or ne proficiscatur. To New York – Neo-Eboraco? – Very often pupils use the Dative, not having been instructed from the beginning about the difference of to, meaning towards, into, and to, meaning for the benefit, in the interest of; here Neo-Eboracum. Now the