Benjamin Franklin, Experiments and Observations on Electricity, Letters I-IV.
Benjamin Franklin is rightly considered the principal founder of the scientific study of electrical phenomena. These Letters are the reports of his experiments, of theories he formed to explain the experiments' results, and more speculative theories he extrapolated from his observations and analysis of his findings.
The single most important discovery noted in these letters is that of polarity, that is, he found that all electrical potentials were not equivalent, but could be observed holding either of two opposite charges. To these he assigned the names we still use, positive and negative. Unfortunately, from our point of view, he assigned them in the opposite sense to our understanding -- "positive" meaning a deficit of free electrons -- which is why we now call the electron a negatively charged particle.
-- What led Franklin to the discovery of electric polarity?
-- Why did he assign the positive value to that charge which we now know indicates a deficiency of free electrons?
-- What was Franklin's explanation for the aurora borealis? How does it compare to our theories?
-- Franklin disgussed at length the role of electric forces in weather. We now know that he greatly exaggerated the role of electricity in shaping weather forces. On what points about weather was he broadly correct, and on what points in error? What might have led him to his erroneous conclusions?
Antoine-Louis Lavoisier. Elements of Chemistry. Introduction, et. al.
Lavoisier, best-known today as the discoverer of oxygen, presents in Introduction to his Elements of Chemistry his general approach to the study of chemistry, and in the following passages he analyses acids, combustion, and gives theories of acid formation and of heat. His approach to chemistry began with an argument for the importance of valid nomenclature, and he went on from that point...