Recent scholarship no longer sees the Midlands Enlightenment as primarily having an industrial or technological focus. Analysis of the subject-matter of Lunar Society meetings shows that its main concern was with pure scientific investigation rather than manufacturing, and the influence of Midlands Enlightenment thinkers can be seen in areas as diverse as education, the philosophy of mind, Romantic poetry, the theory of evolution and the invention of photography. A distinctive and significant feature of the Midlands Enlightenment, however, that partly resulted from Birmingham's unusually high level of social mobility, was the close relationship between the practitioners of theoretical science and those of practical manufacturing. The Lunar Society included industrialists such as Samuel Galton, Jr. as well as intellectuals such as Erasmus Darwin and Joseph Priestley; scientific lecturers such as John Warltire and Adam Walker communicated basic Newtonian principles widely to the town's manufacturing classes; and men such as Matthew Boulton, James Keir, James Watt and John Roebuck were simultaneously highly regarded both as scientists and as technologists, and in some cases also as businessmen. The intellectual climate of 18th century Birmingham was therefore unusually conducive to the transfer of knowledge from the pure sciences to the technology and processes of manufacturing, and the feeding back of the results of this to create a "chain reaction of innovation".