The Grandfather of time, joumal of a meteorologist, is the title of the Msc dissertation based on the analysis of the twenty-eight volumes of the joumal written by Joaquim de Sampaio Ferraz from 1900 to 1940. From the documentation left by an ordinary middle class man, civil servant and urban professional, a family man, it became possible to aprehend ethical values, life sty1e, rules for everyday life, and also to acknowledge his difficulties to develop a scientific career that was new in Brazil and modem for the world of the turn of the twentieth century, a time of rapid changes and transformation. The appreciation of joumals and other types of writing of the self dates back from just a few decades and has arisen interest and motivated the creation of numerous national and international organizatons. In academia the studies are still relatively rare, thus the interest in developing this issue from the sources preserved by the Sampaio Ferraz family over more than a century.