This paper is a study of textbooks in chemical technology in Sweden during the industrialisation in the 19th century. In this period, teaching in technological education in general became more and more founded on science. However, there existed very few textbooks in chemical technology, and it is argued that the reason was that the essentials of the knowledge used for developing chemical industry were of a tacit and local character. Such knowledge could only with difficulty be transferred through textbooks with scientific ambitions. Thus the textbooks written or translated by scientists were not as widely used as the ones written or translated by chemical engineers. The usefulness of the latter group can be explained by the fact that they had been adapted to local circumstances, and expressed generalisations, not as scientific laws, but as rules of thumb. Finally, a model for the diffusion of knowledge is suggested, by which the role of textbooks in chemical technology better can be understood.