Methods and Manipulation on a Semi-micro Scale. INTRODUCTION. When only very small quantities of organic materials are available their manipulation must necessarily be carried out on a correspondingly small scale. This occurs frequently in research prob-lems, but small-scale preparative work is often of value to the student because considerable economy of materials and of time can be achieved. It is emphasised, however, that the proper training for the organic chemist must rest upon the correct understanding and thorough practice of the manipulations on the macro-scale already described, and that he should consider small-scale work as a sequel to and not as a replacement of the above standard techniques. Preparative work is sometimes divided into three categories. This division is entirely arbitrary and the categories overlap, but they may conveniently be classified thus: Scale Remarks (a) Macro. Usually i g. to 200 g. for solids and 5 g. to 200 g. for liquids.
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