This smaller image repeats an element of the main image for Chemistry, a test tube, within which samples can be heated, treated with various reagents, and the results observed. This image shows the test tube is in its laboratory setting, held by a stand over a Bunsen burner for heating. Chemistry has its origins in deep antiquity, where in 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.