Refrigerating by ice will not provide refrigeration temperatures below 32 F. Therefore, to obtain lower temperatures required in some instances, ice and salt mixtures are used. These mixtures, ice and salt (sodium chloride - NaCI) and ice and calcium chloride (CaCI) lower the melting temperature of ice. That is, an ice and salt mixture may be made which will melt at 0 F. The reason that the ice and salt mixture produces lower temperatures is that the salt causes the ice to melt faster and this forced absorption of heat causes the lower temperature which results from the mixture.
