Note 1: After 30 min, cold water (5°C) was added into upper bottle and its contents stirred, note temp. dip on graph. Stir water from time to time.

Note 2 : Efficiency of device is increased if you glue 2 wedges (2 mm thick) onto lower side of PVC ring, to prevent lower glass window touching microscope plate or frosted glass.

Note 3 : In my device, the tube diameter I have used is a little too narrow and flow rate is slowed down. Air tubing for aquarium, as specified in parts list, should work better.

A second experiment has been made with a compound microscope. The light bulb's heating effect is less important and, this time, the device can be used to decrease temperatures to slow the activity of some animals to observe them at leisure. Add two spoonfuls of sodium chloride into half a litre of water, put it into the chiller and make ice cubes with another half a liter of such water, using freezer. Then proceed as with fresh water; salted water/ice temperature reaches - 6 °C. (Don't use it for whisky!)

The graph below shows how it's easy to maintain a slide temperature of ca. 5°C, using salted water and two salted ice cubes in the higher bottle with a water supply temperature of - 5°C. The temperature in the bottle began to increase (red curve) as soon as all the ice had disappeared. But with a half liter bottle you have more than 45 minutes to work with your specimen at 5°C.

Don't forget to rinse chamber after use with distilled water to avoid hard water or salt deposits.

NOTE: The thickness of assembly (PVC ring + glass plates) can prevent moving the condenser nearer slide if device is used on a compound microscope. Use ring of 6 mm thickness max.