It is now almost a cliché to say that chemistry was esteemed throughout the nineteenth century for its practical values, especially for industry. Nevertheless, not much has been known about the teaching of chemical technology in the century beyond the teaching of chemical principles, training in chemical analysis, and the visit and/or apprentice in chemical works. Important as these elements are, they would not satisfy the needs of those who were really in needs of such teaching. How, for example, could one learn the operation and construction of an apparatus in a factory without seeing “the real thing”? This paper looks at the often neglected role of book illustrations in making chemical technology “travel,” that is teachable in a variety of countries beyond already industrialized regions such as England and France. For this purpose I shall focus on one richly illustrated reference book of worldwide importance in chemical technology published in the mid-century: Edmund Ronalds, Thomas Richardson and Henry Watts, Chemical Technology, or Chemistry in Its Application to the Arts and Manufactures, Second Edition, vol. 1, parts 1-5 (London: Hyppolyte Baillière, 1855-1867). Chemical Technology started its life as the first edition of a translation of F. Knapp, Lehrbuch der chemischen Technologie: zum Unterricht und Selbststudium (2 Bde. Braunsweig: Friedrich Vieweg und Sohn, 1848-1853) and after thorough revision became an international bestseller, sold in England, the United States and even as far afield as in Japan. By comparing different editions and examining examples of their usage in different pedagogical settings, I aim to answer the following questions: how did Knapp get the idea of using illustrations in his book and his teaching at the University of Giessen? Why did Ronalds and Richardson choose Knapp? What printing technologies made their production possible? How did its revision get momentum from Ronalds’ teaching at Queen’s College Galway in Ireland? Did their revision substantially alter the character and role of illustrations? Most important of all, what information did readers in different parts of the globe glean from illustrations as well as from texts, and how did they learn to do that? In conclusion I would emphasize the active role of students-readers and of how authors perceive their “backwardness” and “needs” in determining the methods and contents of teaching, making this endeavour a two-way street.