Directions for the building of a pocket microscope that will make visible the details of insect structure and living bacteria are described. Background information on the history of microscopes and lenses is provided. The procedures for producing various types of lenses are included. (KR)

Presented is a way to measure the sun's radiation by using a radiometer. Directions for building both simple and complex radiometers, circuit diagrams, and an explanation on how they work are included. (KR)