Instruction paper from the International Correspondence Schools on laboratory testing of raw silk, covering the winding test, the sizing tests (regular 450-meter, American 225-meter, conditioned and compound) and the cohesion test. It describes sampling, preparing and weighing skeins, computing breaks per 100,000 yards, range and average denier, and the machines used (winding frame, sizing reel, quadrant balance, cohesion-card winder and cohesion machine). It includes illustrated apparatus, sample laboratory record forms and certificates, grading tables, and a set of examination questions for students.

Part 3 of an International Correspondence Schools instruction paper on silk testing, covering additional tests for raw and thrown silk. It describes the serimeter test (breaking strength and evenness), the serigraph test (strength, elasticity, elongation), the gauge test for defects and cleanness, the twist test, the mirror test for evenness, and the measuring test for skein length. Each section explains the apparatus, sampling, procedure, laboratory record forms and testing-house certificates, with worked rules and examples. Examination questions are at the end.