In this paper we analyse the early development of the steam engine as a search process in a multidimensional design space. This perspective allows us to make use of recent insights coming from complex systems theory, in particular, of a generalized version of Kauffman's NK-model. We analyse yearly distributions of steam engine designs and their sectors of application for the period 1760-1800. We interpret the patterns of variety and differentiation characterizing the behaviour of these distributions as emerging properties of underlying search processes unfolding in the design space. We conclude that the early development of steam power technology can be understood as a process of technological speciation' of various engine designs in distinct users' niches. 10.1093/icc/dth017