This is a pretty awesome text, courtesy of the Google Books project. Hofmann was one of the early great titans of organic chemistry in the 19th century, and this set of lectures is a terrific snapshot of the field of chemistry at one of the most interesting points in its history.

This was published only a few decades after John Dalton hypothesized that atoms existed, but decades before the ideas of electrons and protons. It was contemporary with the time that Dmitri Mendeleev was formulating the periodic table. The discoveries of chemistry at this time were taking advantage of key theoretical developments in thermodynamics and physics, and setting the stage for some of the most famous discoveries in physics of the 20th century, including quantum mechanics. Chemistry was driving the creation of some the great industrial developments of the 19th century, including synthetic chemicals, which would eventually result in the spectacularly successful organic chemistry research of the mid-twentieth century. It really was a revolutionary time for chemistry.