ABSTRACT
The conversion of a liquid into a vapour and increase in volume of a gas or vapour, are both processes which naturally take place when heat is supplied, so that if the processes are carried on without artificial supply of heat the liquid or vapour or gas becomes cooled. The earliest methods of refrigeration in use on the Atlantic were the circulation of water cooled by ice and salt, and the circulation of air which had been compressed and afterwards cooled by expansion. In the ’eighties ammonia compression machines came into use, and either ammonia or carbon dioxide is regularly employed. Refrigeration serves a special purpose in the Royal Navy. Among the enormous amount of machinery with which the vessels of the Navy are filled, are to be found refrigerating machines which not only preserve the food, but also maintain the ammunition in good condition.
