High Frequency Apparatus Page xiv

xiv CONTENTS Chapter XVI. HIGH FREQUENCY PLANT CULTURE Generation of High Frequency Current for Long Continued Periods of Time. The Problem Involved. Careful Workmanship Essential. Construction of the Generating Apparatus. Data for Various Commercial Voltages and Frequencies. Building of the Transformer. Assembling and Mounting. Construction of the Condenser. Provision for Cooling. The Self-Cooling Spark Gap. The Oscillation Transformer. Installation of the Apparatus. The Transformer Shed. Switches and Control Devices. Protection from Accidental Shock. Wiring the Plot to be Cultivated. Ground Connection and Overhead Net Work. Operation of the Apparatus. Time of Treatment. Value of Comparative Data. High Tension Electrical Stagecraft. 153 Chapter XVII. A FOREWORD ON THE CONSTRUC177 TION OF ELECTRICAL APPARATUS FOR THE STAGE Opportunities of High Potential Electricity for the Professional Entertainer. Chance to Improve upon Past Offerings. Importance of High Frequency Apparatus. Points to Consider before Starting Work. Cost and Weight of Apparatus. Difference between the Lecturer and the Vaudeville Artist. Current Required and Difficulties of Obtaining It. Where and How to Build the Apparatus. The Home Workshop and Its Equipment. Some Work Done Outside if Large and Expensive Tools are not Available. Advantages of Doing Work at Home. Working Drawings and Blueprints. Need for Practical Working Knowledge of Subject. How to Obtain this Knowledge. Mathematics Unnecessary. Chapter XVIII. CONSTRUCTION OF LARGE HIGH FREQUENCY APPARATUS Design for a Resonator Producing a Five-Foot Spark. Details of Construction. Building the Secondary Cylinder. The Winding. Building the Primary. Assembly of the Coil. Connecting Cable and Clips. The 183