The effect of human capital on growth involves multiple channels. On the one hand, an increase in human capital directly affects economic growth by enhancing labor productivity in production. On the other hand, human capital is an important input into R&D and therefore increases labor productivity indirectly by accelerating technological change. In addition, different types of human capital such as basic and higher education or training-on-the-job might play different roles in both production and innovation activities. We merge individual data on valuable patents granted in Prussia in the late nineteenth-century with county-level data on literacy, craftsmanship, secondary schooling, and income tax revenues to explore the complex relationship between various types of human capital, innovation, and income. We find that the Second Industrial Revolution can be seen as a transition period when it comes to the role of human capital. As in the preceding First Industrial Revolution, "useful knowledge" embodied in master craftsmen was related to innovation, especially of independent inventors. As in the subsequent 20 th century, the quality of basic education was associated with both workers' productivity and firms' R&D processes. In a final step, we show that literacy had also a negative effect on fertility which increased with innovation. In general, our findings support the notion that the accumulation of basic human capital was crucial for the transition to modern economic growth.