Chemistry explores the composition of our world by separating matter into its fundamental components and recombining them in various ways. The main image shows Chemistry using two essential tools: a precise balance to determine weights of samples and a test tube, within which samples can be heated, treated with various reagents, and the results observed. Two smaller images depict the test tube in its laboratory setting and a retort, wherein materials can be heated and mixed, and their products carefully controlled and extracted over time. Chemistry has its origins in deep antiquity. Through primitive metallurgy, jewelry-making, brewing, cooking, and other activities craftspeople advanced knowledge of techniques and accumulated procedures and recipes. This valuable knowledge was kept secret, passed from master to student, and in its developed form became alchemy in the middle ages and renaissance. Antoine Lavoisier (1734-1794), with his English competitor Joseph Priestley (1733-1804), is widely regarded as the "father of modern chemistry", particularly for his pioneering work on the role of oxygen in combustion and respiration. Lavoisier completely overhauled chemical theory and the concept of elements, replacing the original four with a larger set that he identified with the tools depicted here. Lavoisier combined the precision of the balance with the analyzing ability of heat and acids in test tubes and retorts to identify and isolate the new elements.
