«Scientifica» - the collection of scientific instruments in the St. Petersburg Kunstkamera, the first Russian museum founded in 1714 - is much less known and studied in comparison with the museum's other collections in natural history («Naturalia») and the arts and trades («Artificialia»). The core of the collection came from instruments acquired by Peter the Great in Europe. Unlike typical museum objects, the instruments were not merely preserved and displayed, but actively used in the production and dissemination of scientific knowledge. They formed the basis of experimental research at the St. Petersburg Academy of Sciences from the moment of its foundation in 1725. The article uses archival and other sources to analyze the history and structure of the Kunstkamera's instrument collection prior to the devastating fire of 1747. It shows the role these instruments played in the early stages of the development of Russian metrology, time keeping, meteorology, and cartography. It also describes the tradition of public «entertaining» experiments that helped attract the attention of Russian society to the museum's collection in particular, and to scientific knowledge in general.