The exercises in this manual may be selected or easily modified, so that they will be suitable for any laboratory equipment. For example, the receipts have been prepared with the expectation that a 10-gallon freezer would be used; if a smaller freezer is used, the receipts may be reduced proportionally. Much better instruction can be given if the equipment includes an artificial refrigerating plant for freezing and hardening the ice cream. If the equipment does not include an artificial refrigerating plant, a tub and can freezer, using an ice and salt mixture for freezing, and a wooden box for packing and hardening the ice cream, in ice and salt, may be used. The hardening box should be made of 2 inch matched lumber so that it will not leak. The size of the box will be determined by the amount of ice cream manufactured. It should be built in compartments which will hold six five gallon cans. This will require a box 26 inches wide by 32 inches deep by 36 inches long, outside measurement, with a hinged cover for each compartment. If much ice cream is to be made an ice cream mixer is a necessity, but if a small amount is made each batch may be mixed in a 40 quart milk can. A homogenizer and emulsor may be included in the equipment. With whatever type of freezer is used, there should be one or two small hand freezers, to freeze small batches and to try new receipts. An ice crusher should be included for crushing ice. The equipment should include the necessary small utensils, such as pails, dippers, ladles, spoons, thermometers, scales, measures, pack cans, etc. There should be a suitable sink connected with hot and cold water and steam, for washing and scalding the utensils. A suitable rack should be provided for drying and holding the utensils and pack cans. Because of the salt used, care must be exercised, as it is liable to get on the utensils and cause them to rust. All belts and gears on machines should be protected, so that persons cannot be caught and injured in them. EXERCISE NUMBER I INSPECTION AND STUDY OF ICE CREAM MACHINERY _Artificial refrigerating systems._ I. State briefly the principles involved in an artificial refrigerating plant. II. Make drawings showing the working principles of the refrigerating system. III. Tell how to start and stop the compressor. _Ice cream freezers._ I. Tell the principles on which the various types of freezers work. II. How can the temperature in the different types of freezers be regulated? _Cleaning utensils._ I. How should utensils be washed? Why? II. Are all utensils so constructed that they may be easily and thoroughly cleaned? What provisions have been made to make cleaning easy? EXERCISE I REPORT STANDARDIZATION