The Icebox: Drain the Melt, Shut the Ice Off When the Door Opens

"The objects of my invention are to preserve the ice from rapidly melting, to retain the air free from excessive humidity, and to protect the ice from the effects of currents of warm air entering the main chamber upon the door communicating therewith being opened." "The ice-shelves are formed of two inclined planes, covered with zinc or other sheet metal ... and on top of these shelves is laid a lattice-work of wood or metal strips, upon which the ice is laid, and by means of which the drip-water from the dissolving ice is drained off", "thus securing the ice from contact with the water, which, being of a higher temperature, would cause more rapid dissolution if allowed to surround the ice". Slides "upon the door communicating with the main chamber being opened, close the apertures having access to the ice-shelves, thus excluding warm currents of air." "While the doors communicating with the exterior are closed, a constant circulation of air takes place within the refrigerator. The more rarefied portions, ascending ... and coming in contact with the ice, are condensed, and descend into the cold-air chamber and storage-chamber".

Line two identical storage boxes with foam board, and make lids of foam board too. Freeze two equal blocks of ice in loaf pans and weigh each. In the first box stand the block on a rack over a tray so the melt drips away from it. In the second put the block straight on the floor of the box so it sits in its own melt. Put a thermometer in each and close them. After six hours, and again after twelve, record the air temperature, lift each block out, wipe it and weigh it. Plot ice left over time for both: that is Gasper's drainage at work. Then open one lid every half hour for a day and compare.

**Simon Gasper** of Indianapolis filed US 190,846 on 4 October 1876; it is dated 15 May 1877. A valved ventilator on top lets air compressed by the closing door escape. **Honest limits.** The latent heat is a physical constant; the wall conductivities, sizes, temperatures and door air volume in the notebook are examples. Your weighings are the measurement.