Benedetto Varchi (Florence, 1503-1565), in his lectures (in Accademia Fiorentina) in the years 1543-1564, dedicated mostly to "Divine Comedy" by Dante, provided basis for development of scientific literature in Italian language. Humanist (man of letters), highly educated (in the universities in Padua and Bologna), created expositions of logic studies in Italian language, translating and giving scientific comments on Aristotle’s ideas. From those studies only some manuscripts concerning systematisation and methodology of lectures in scientific knowledge (“exposition” and “explanation”) were published in the nineteenth century. Varchi designed his lectures on basis of “proper way of cognition and knowledge” – synthetic, analytic and defining – indispensable to conduct reasoning and to define research subject. So, he created prose appropriate to exact and natural science, as well as to lectures for diverse audience. Those texts reflect the methodology used in sequence of reasons, in syntax and in terminology which revealed meanings of phenomena. The analysis of syntax, the text construction and the terminology used, carried out in this article, discover and highlight a quality of lectures by Varchi. Lectures that can be an example of new prose which fully developed in scientific texts of the seventeenth century - mostly because of rich and precise scientific language (coming from Greek and Latin), but also enriched by neologisms, as well as by new stylistic based on short sentences, rarely compound, and by creation of sentences based on nouns.